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COLLEGE OF PHYSICIANS AND SURGEONS
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Reference Library
Given by
Robert ■ Gr.oj\tnor. •
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[;iANS,
THE PRINCIPLES AND PRACTICE OF MEDICINE
DESIGNED FOR THE USE OF PRACTITIONERS AND STUDENTS OF MEDICINE
BY
WILLIAM OSLER, M.D.
FELLOW OF THE ROYAL SOCIETY ; FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS, LONDON; REGIUS PROFESSOR OF MEDICINE, OXFORD UNIVERSITY; HONORARY PRO- FESSOR OF MEDICINE, JOHNS HOPKINS UNIVERSITY, BALTIMORE ; FORMERLY PROFESSOR OF THE INSTITUTE OF MEDICINE, McGILL UNIVERSITY, MONTREAL, AND PROFESSOR OF CLINICAL MEDICINE IN THE UNIVERSITY OF PENNSYLVANIA, PHILADELPHIA
SEVENTH EDITION, THOROUGHLY REVISED
NEW YORK AND LONDON
D. APPLETON AND COMPANY
1909
COPTRIGHT, 1892, 1895, 1898, 1901, 1903, 1903. 1904, 1905, 1909, By D. APPLETON AND COMPANY
FEINTED AT THE APPLETON PEESS NEW YOEK, U. S. A.
TO THE
ittetttorg of ms ®eacl)crs : WILLIAM ARTHUR JOHNSON,
. PEIEST OP THE PARISH OF WESTON, ONTARIO.
JAMES BOVELL,
OF THE TORONTO SCHOOL OF MEDICINE, AND OF THE UNIVERSITY OF TRINITY COLLEGE, TORONTO.
ROBERT PALMER HOWARD,
DEAN OF THE MEDICAL FACULTY AND PROFESSOR OF MEDICINE, MCGILL UNIVERSITY, MONTREAL.
Digitized by the Internet Arciiive
in 2010 with funding from
Open Knowledge Commons
http://www.archive.org/details/principlespractiOOosle
PREFACE TO THE SEVENTH EDITION.
The three years that have passed since the last edition have been rich in additions to our knowledge of disease and its treatment, particularly in con- nection with the acute infections. I have incorporated all the more impor- tant advances — the long-expected epoch-making discoveries in syphilis, the work of the New York Pneumonia Commission, the triumph of the British army and naval surgeons in stamping out Malta fever, the splendid work of Gorgas and his colleagues at Panama, the studies of Strong and his asso- ciates in the Philippine Islands, the fresh work which has been done in trypanosomiasis psorosomiasis, tropical splenomegaly, the experiences of the last epidemic of cerebro-spinal fever in New York, Belfast, and Glasgow, with the hopeful work of Flexner at the Eockefeller Institute, the all-important contributions on " carriers " in the acute infections, the results of the Wash- ington Congress with the new views on infection, heredity, diagnosis, and treatment of tuberculosis, the remarkable studies upon epidemic anterior poliomyelitis, and the work upon Eocky Mountain fever, milk sickness, and the serum disease. One cannot but be impressed with the extraordinary rapid- ity of the progress of our knowledge of the acute infections !
The section on parasites has been carefully revised, and has received many additions. In the chapters on the diseases of special organs much new matter has been incorporated — a new section in acute dilation of the stomach, a complete revision of the subject of peptic ulcer in the light of recent surgical work, new sections on diverticulitis, parotitis, pancreatic and adrenal insuffi- ciency, oedema of the lungs, Banti's disease, polycythsemia, etc. In the sec- tion upon Diseases of the Nervous System the studies of Marie and his pupils upon aphasia and the new work on spastic paraplegia, Oppenheim's disease, posterior basic meningitis, psychasthenia, etc., have been incorporated.
The new points which have come up in treatment have been discussed, particularly the important advances in serum therapy and on the surgical treatment of internal diseases, and I have added a note on the cult of the day
vi: PREFACE TO THE SEVENTH EDITION.
— faith healing. In addition to these, scores of minor alterations have been made, too numerous to mention.
Since the ajjpearance of the last edition the work has appeared in French, translated by MM. Salomon and Lazard under the supervision of Professor Marie (Steinheil & Cie., Paris) ; and in German, translated by Dr. Edmund Hoke, with additions by Professor von Jaksch, of Prague. Spanish and Clii- nese translations are in course of preparation.
I have many to thank — my fellow-teachers in the medical schools of the English-speaking world for their kind reception of previous editions, many friends for suggestions and advice, scores of practitioners all over the world for interesting memoranda of cases; Dr. Broome, of Messrs. D. Appleton and Comj)any, for his kind help in many ways, and my nephew. Dr. W. W. Erancis, of Montreal, who has seen the proofs of this edition through the press.
William Oslek.
CONTENTS.
SECTION I. DISEASES DUE TO ANIMAL PARASITES.
PAGE
A. Diseases due to Protozoa i
I. Psorospermiasis 1
II. Amoebic Dysentery 2
III. Trypanosomiasis 7
IV. Tropical Splenomegaly (Tropical Cachexia) 9
V. Malarial Fever 10
Intermittent Fever 16
Continued and Remittent Malarial Fevers 20
Pernicious Malarial Fever 21
Malarial Cachexia 23
B. Diseases due to Parasitic Infusoria 25
C. Diseases due to Flukes (Distomiasis) . . . . . . . . . . 26
D. Diseases caused by Cestodes 28
I. Intestinal Cestodes; Tape-worms 28
II. Visceral Cestodes 31
Cysticercus Cellulosse 31
Echinococcus Disease . . . ' 32
Multilocular Echinococcus 37
E. Diseases caused by Nematodes 38
I. Ascariasis . 38
II. Trichiniasis 39
III. Ankylostomiasis 44
IV. Filariasis _ 47
V. Dracontiasis 49
VI. Other Nematodes 50
Acanthocephala 51
F. Parasitic Arachnida and Ticks 52
G. Parasitic Insects 53
H. Parasitic Flies (Myiasis) 55
SECTION II. SPECIFIC INFECTIOUS DISEASES.
I. Typhoid Fever 57
II. Typhus Fever . . . 105
III. Relapsing Fever 109
IV. Small-pox 112
Variola Vera 115
Hsemorrhagic Small-pox 117
Varioloid 119
V. Vaccinia (Cow-pox) — Vaccination 123
VI. Varicella (Chicken-pox) 128
VII. Scarlet Fever 130
VIII. Measles (Morbilli Rubeola) 140
IX. Rubella (Rotheln, German Measles) . 145
X. Epidemic Parotitis (Mumps) 146
XI- Whooping-cough ,,,,,, 148
vii
vni
CONTENTS.
XII.
XIII.
XIV.
XV.
XVI.
XVII.
XVIII.
XIX.
XX.
XXI.
XXII.
XXIII.
XXIV.
XXV.
XXVI.
XXVII.
XXVIII.
XXIX.
XXX.
XXXI.
XXXII. XXXIII.
XXXIV. XXXV.
Influenza.
Dengue .
Cerebro-spinal Fever
Pneumonia
Diphtheria
Erysipelas
Septicaemia and Pysemia
Septicaemia
Septico-Pyaemia .
Terminal Infections Rheumatic Fever . Cholera Asiatica . Yellow Fever . The Plague Bacillary Dysentery Malta Fever . Beri-beri Anthrax . Hydrophobia . Tetanus . Glanders Actinomycosis Syphilis .
Acquired
Congenital .
Visceral Gonorrhoeal Infection Tuberculosis .
I. General Etiology and Morbid Anatomy II. Acute Tuberculosis
III. Tuberculosis of the Lymphatic System
IV. " of the Lungs (Phthisis, Consumption) V. " of the Alimentary Canal
VI. " of the Liver
VII. " of the Brain and Spinal Cord
VIII. " of the Genito-urinary System
IX. " of the Mammary Gland .
X. " of the Circulatory System
XI. Diagnosis of Tuberculosis XII. Prognosis in Tuberculosis
XIII. .Prophylaxis in Tuberculosis .
XIV. Treatment of Tuberculosis
Leprosy
Infectious Diseases of Doubtful Nature
1. Febricula (Ephemeral Fever)
2. Infectious Jaundice (Weil's Disease)
3. Milk-sickness
4. Glandular Fever ....
5. Mountain Fever ....
6. Miliary Fever (Sweating Sickness)
7. Foot and Mouth Disease .
8. Psittacosis
9. Rocky Mountain Spotted Fever — ^Tick Fever 10. Swine Fever
CONTENTS.
IX
SECTION III. THE INTOXICATIONS AND SUN-STROICE. Alcoholism .
1. Acute Alcoholism
II. III. IV.
V.
VI.
I.
II.
III.
IV.
V.
VI.
VII.
VIII.
2. Chronic Alcoholism
3. Delirium Tremens Morphia Habit . Lead Poisoning . Arsenical Poisoning . Food Poisoning .
1. Meat Poisoning .
2. Poisoning by Milk Products
3. Poisoning by Shell-fish and Fish
4. Grain and Vegetable Food Poisoning Sun-s,troke
SECTION rv.
CONSTITUTIONAL DISEASES.
Arthritis Deformans
Chronic Rheumatism
Muscular Rheumatism ..,.„..
Gout .. = ..,
Diabetes Mellitus ..... o . . Diabetes Insipidus . . . .
Rickets , . .
Obesity * .
PAGE
369 369 369 371 373 375 379 380 381 382 383 383 385
389 394 396 397 408 424 426 431
. SECTION V. DISEASES OF THE DIGESTIVE SYSTEM.
A. Diseases of the Mouth 434
Stomatitis _ 434
Acute Stomatitis <> . . 434
Aphthous Stomatitis 434
Ulcerative Stomatitis . 435
Parasitic Stomatitis (Thrush) . . . 436
Gangrenous Stomatitis 437
Mercurial Stomatitis 437
Geographical Tongue (Eczema of the Tongue) ....... 438
Leukoplakia buccalis 439
Fetor Oris 439
Oral Sepsis •• = ...... 440
Affections of the Mucous Glands 440
B. Diseases of the Salivary Glands 440
Supersecretion , 440
Xerostomia 441
Inflammation of the Salivary Glands . . « , . . . o . .441
C. Diseases of the Pharynx ............. 442
Circulatory Disturbances 442
Acute Pharyngitis 442
Chronic Pharyngitis 443
Ulceration of the Pharynx 443
Acute Infectious Phlegmon of the Pharynx . . , . . . . . 444
Retro-pharyngeal Abscess 444
Angina Ludovici . , , . . . . . 444
X CONTENTS.
PAGE
D. Diseases of the Tonsils „ . . . . 445
I. Acute Tonsillitis 445
Follicular or Lacunar Tonsillitis ........ 445
Suppurative Tonsillitis 446
II. Chronic Tonsillitis 447
E. Diseases of the ffisophagus 451
■ I. Acute (Esophagitis 451
II. Spasm of the (Esophagus 453
III. Stricture of the (Esophagus - 453
IV. Cancer of the (Esophagus 454
V. Rupture of the (Esophagus 455
VI. Dilatations and Diverticula 456
F. Diseases of the Stomach 456
I. Acute Gastritis 456
Phlegmonous Gastritis 458
Toxic Gastritis 458
Diphtheritic Gastritis 459
Mycotic or Parasitic Gastritis ......... 459
II. Chronic Gastritis (Chronic Dyspepsia) 459
III. Dilatation of Stomach 467
IV. The Peptic Ulcer, Gastric and Duodenal 470
V. Cancer of Stomach 479
VI. Hypertrophic Stenosis of the Pylorus 486
VII. Hgemorrhage from the Stomach 487
VIII. Neuroses of the Stomach 490
G. Diseases of the Intestines . . • 497'
I. Diseases of the Intestines associated with Diarrhoea .... 497
Catarrhal Enteritis: Diarrhoea . . .• 497
Diphtheritic or Croupous Enteritis 500
Phlegmonous Enteritis 501
Ulcerative Enteritis 501
11. Diarrhoea! Diseases in Children ......... 504
III. Appendicitis (Typhlitis and Perityphlitis) 512
IV. Intestinal Obstruction 519
V. Constipation (Costiveness) 525
VI. Enteroptosis (Glenard's Disease) 528
VII. Miscellaneous Affections 530
Mucous Colitis 530
Dilatation of the Colon . . . .531
Intestinal Sand • 532
Diverticulitis — Perisigmoiditis 532
Affections of the Mesentery 532
H. Diseases of the Liver 534
I. Jaundice (Icterus) 534
II. Icterus Neonatorum 538
III. Acute Yellow Atrophy 538
IV. Affections of the Blood-vessels of the Liver 540
V. Diseases of the Bile-passages and Gall-bladder 542
VI. Cholelithiasis 548
VII. Cirrhoses of the Liver 556
VIII. Abscess of the liiver . 563
IX. New Growths in the Liver 567
X. Fatty Liver 570
XI. Amyloid Liver 571
XII. Anomalies in Form and Position of the Liver ,,,,.. 572
CONTENTS.
XI
PAGE
I. Diseases of the Pancreas 573
I. Insufficiency 573
II. Hsemorrhage 573
III. Acute Pancreatitis 574
IV. Chronic Pancreatitis 577
V. Pancreatic Cysts ■ 577
VI. Tumors of the Pancreas 579
VII. Pancreatic Calcuh . . . • 530
J. Diseases of the Peritonaeum 5g0
I. Acute General Peritonitis 580
II. Peritonitis in Infants 534
III. Localized Peritonitis 584
IV. Chronic Peritonitis 586
V. New Growths in the Peritonaeum 588
VI. Ascites (Hydro-peritonseum) 589
SECTION VI. DISEASES OF THE RESPIRATORY SYSTEM.
A. Diseases of the Nose 593
I. Acute Coryza 593
II. Autumnal Catarrh (Hay Fever) 594
III. Epistaxis 595
B. Diseases of the Larynx 595
I. Acute Catarrhal Laryngitis , 596
II. Chronic Laryngitis _ 597
III. Edematous Laryngitis 598
IV. Spasmodic Laryngitis (Laryngismus stridulus) 598
V. Tuberculous Laryngitis 6qq
VI. Syphilitic Laryngitis gQj
C. Diseases of the Bronchi . ' g02
I. Acute Bronchitis . , 6Q2
II. Chronic Bronchitis 594
III. Bronchiectasis qqq
IV. Bronchial Asthma 609
V. Fibrinous Bronchitis 513 '
D. Diseases of the Lungs gl4
I. Circulatory Disturbances in the Lungs 614
II. Broncho-pneumonia (Capillary Bronchitis) 620
III. Chronic Interstitial Pneumonia (Cirrhosis of Lung) 628
IV. Pneumonokoniosis 631
V. Emphysema 633
Compensatory Emphysema . 633
Hypertrophic Emphysema 634
Atrophic Emphysema 638
Acute Vesicular Emphysema . 638
Interstitial Emphysema 638
VI. Gangrene of the Lung 638
VII. Abscess of the Lung 640
VIII. New Growths in the Lungs 641
E. Diseases of the Pleura 643
I. Acute Pleurisy 643
Fibrinous or Plastic Pleurisy ...00.... 643
Sero-fibrinous Pleurisy . . . 643
Purulent Pleurisy (Empyema) 648
xii CONTENTS.
PAGE
Tuberculous Pleurisy 650
Other Varieties of Pleurisy 650
II. Chronic Pleurisy 655
III. Hydrothorax . 656
IV. Pneumothorax (Hydro-pneumothorax and Pyo-pneumothorax) . . 657 V. Affections of the Mediastinum 660
SECTION VII. DISE.\SES OF THE KIDNEYS.
I. Malformations 664
II. Movable Kidney 664
III. Circulatory Disturbances 667
IV. AnomaHes of the Urinary Secretion 668
1. Anuria 668
2. Haematuria 669
3. Haemoglobinuria . , 670
4. Albuminuria 672
5. Pyuria (Pus in the Urine) 676
6. Chyluria (Non-parasitic) 676
7. Lithuria ... ... , 677
8. Oxaluria ................ 678
9. Cystinuria 679
10. Phosphaturia . . . o 679
11. Indicanuria ......... .... 680
12. Melanuria 680
13. Alkaptonuria and Ochronosis . 681
14. Pneumaturia 681
15. Other Substances ............ 682
V. Uraemia 683
VI. Acute Bright' s Disease ............ 686
VII. Chronic Bright's Di.sea.se ............ 692
Chronic Parenchymatous Nephritis . , ■ . 692
Chronic Interstitial Nephritis ........... 694
VIII. Amyloid Disease .702
IX. Pyelitis 703
X. Hydronephrosis 707
XL Nephrohthiasis (Renal Calculus) .„ ... 709
XII. Tumors of the Kidney » .... 713
XIII. Cystic Disease of the Kidney o 715
XIV. Perinephric Abscess 717
SECTION VIII. DISEASES OF THE BLOOD AND DUCTLESS GLANDS.
I. Ansemia 718
Secondary Ansemia 719
Primary or Essential Ansemia 721
II. Leuksemia 731
III. Hodgkin's Disease 738
IV. Purpura 742
V. Hsemophilia 747
VI. Scurvy . 750
VII. Status L;\Tnphaticus (L\Tnphatism) . ... ...... 755
VIII. Diseases of the Suprarenal Bodies 756
Addison's Disease 756
CONTENTS. xiii
PAGE
IX. Diseases of the Spleen 760
Movable Spleen 760
Rupture of the Spleen 761
Infarct and Abscess of the Spleen 761
Splenomegaly 762
Chronic Polycythsemia with Cyanosis and Enlarged Spleen .... 762
X. Diseases of the Thyroid Gland . . . o 763
Congestion 763
Acute Thyroiditis .763
Goitre 763
Tumors of the Thyroid 764
Exophthalmic Goitre 765
Myxoedema 768
XI. Diseases of the Thymus Gland 771
XII. Infantilism 773
SECTION IX.
DISEASES OF THE CIRCULATORY SYSTEM.
Diseases of the Pericardium 775
I. Pericarditis 775
II. Other Affections of the Pericardium 784
Diseases of the Heart 785
I. Endocarditis 785
Acute Endocarditis 785
Chronic Endocarditis ....;...,,. 792
II. Chronic Valvular Disease ......' 793
General Introduction 793
Aortic Incompetency ..«.-<...,.. 796
Aortic Stenosis 802
Mitral Incompetency 804
Mitral Stenosis 808
Tricuspid Valve Disease . .811
Pulmonary Valve Disease . , . 813
Combined Valvular Lesions .......... 813
III. Affections of the Myocardium .......... 820
Dilatation and Hypertrophy 820
Lesions due to Disease of the Coronary Arteries 823
Acute Interstitial Myocarditis 824
Fragmentation and Segmentation 825
Parenchymatous Degeneration 825
Fatty Heart . ■ 825
Other Degenerations of the Myocardium . 826
IV. Aneurism of the Heart 830
V. Rupture of the Heart 830
VI. New Growths and Parasites 831
VII. Wounds and Foreign Bodies 831
VIII. Functional Affections of the Heart 832
Palpitation 832
Arrhythmia 833
Rapid Heart (Tachycardia) . . o . ., , . . . 835
Slow Heart (Bradycardia) Heart Block . . . , „ . . 836
Heart Block (Stokes- Adams Disease) 837
xiv ■ CONTENTS.
PAGE
IX. Angina Pectoris 839
X. Congenital Affections of the Heart 843
C. Diseases of the Arteries 847
I. Degenerations 847
II. Arterio-sclerosis (Arterio-capillary Fibrosis) 847
III. Aneurism 853
Aneurism of the Thoracic Aorta 855
Aneurism of the Abdominal Aorta 863
Aneurism of the Branches of the Abdominal Aorta. .... 865
Arterio-venous Aneurism 865
Polyarteritis Acuta Nodosa (Periarteritis Nodosa) .... 866
SECTION X. DISEASES OF THE NERVOUS SYSTEM.
A. General Introduction 867
B. System Diseases 885
I. Introduction 885
II. Diseases of the Afferent or Sensory System 886
Locomotor Ataxia 886
General Paralysis of the Insane and Tabo-Paralysis .... 895
Herpes Zoster 900
III. Diseases of the Efferent or Motor Tract 901
A. Of the whole Tract 901
Progressive (Central) Muscular Atrophy 901
Bulbar Paralysis 904
Progressive Neural Muscular Atrophy ...... 905
The Muscular Dystrophies ......... 906
B. System Diseases of the Upper Motor Segment 909
Spastic Paralysis of Adults 909
Spastic Paralysis of Infants 910
Hereditary Spastic Paraplegia .912
Erb's Sj^philitic Spinal Paralysis 913
Secondary Spastic Paralysis 913
Hysterical Spastic Paraplegia .' 914
C. System Diseases of the Lower ^lotor Segment 914
Chronic Anterior Polio-myelitis . .914
Ophthalmoplegia . . .914
Acute Anterior Polio-myelitis - . .914
Acute and Subacute Polio-myelitis in Adults ..... 918
Acute Ascending (Landry's) Paralysis 918
IV. Combined System Diseases 919
Ataxic Paraplegia 920
Primary Combined Sclerosis (Putnam) 920
Hereditary Ataxia (Friedreich's Ataxia) 921
Progressive Interstitial Hj-pertrophic Neuritis of Infants . . . 922
Toxic Combined Sclerosis 922
C. Diffuse Diseases of the Nervous System 923
I. Affections of the Meninges 923
Diseases of the Dura Mater (Pachymeningitis) 923
Hsemorrhagic Pachymeningitis . . . . = . . . . 923
Diseases of the Pia Mater ..... o«.. . 925
Simple Meningitis of Infants .0.00 = 00. 928
TI. Scleroses of the Brain . . , <, » » » o « o . 928
CONTENTS. XV
PAGE
D. Diffuse and Focal Diseases of the Spinal Cord ........ 931
I. Topical Diagnosis 931
II. Affections of the Blood-vessels 934
Congestion 934
Ansemia 934
Embolism and Thrombosis 935
Endarteritis 935
Haemorrhage into the Spinal Membranes » . 935
Haemorrhage into the Spinal Cord 936
Caisson Disease 937
III. Compression of the Spinal Cord 938
Lesions of the Cauda Equina and Conus MeduUaris .... 940
IV. Tumors of the Spinal Cord and its Membranes 941
V. Syringomyelia • 943
IV. Acute Myelitis 944
E. Diffuse and Focal Diseases of the Brain . 947
I. Topical Diagnosis .... o ....-• - 947
II. Aphasia 955
III. Affections of the Blood-vessels . 961
Cerebral Circulation . . . .961
Hypersemia and Anaemia 964
CEdema of the Brain 965
Cerebral Haemorrhage 966
Embolism and Thrombosis . 977
Aneurism of the Cerebral Arteries - . • 982
Endarteritis 983
Thrombosis of the Cerebral Sinuses and Veins 983
Hemiplegia in Children . 985
IV. Tumors, Infectious Granulomata, and Cysts of the Brain .... 988 V. Inflammation of the Brain 992
Acute Encephalitis 992
Abscess of the Brain 993
VI. Hydrocephalus 996
F. Diseases of the Peripheral Nerves 998
I. Neuritis (Inflammation of the Bundles of Nerve Fibres) .... 998
II. Neuromata 1004
III. Diseases of the Cerebral Nerves 1005
Olfactory Nerves and Tracts 1005
Optic Nerve and Tract 1006
Lesions of the Retina 1006
Lesions of the Optic Nerve • • 1008
Affections of the Chiasma and Tract 1009
Affections of the Tract and Centres ....... 1010
Motor Nerves of the Eyeball 1013
Fifth Nerve 1017
Facial Nerve 1019
Auditory Nerve 1023
The Cochlear Nerve 1023
The Vestibular Nerve 1024
Glosso-pharyngeal Nerve . . . . . o » . . ■ 1026
Pneumogastric Nerve ..... o...- • 1027
Spinal Accessory . . . . . • 1030
Hypoglossal Nerve. . . . . « . . . • • • 1032
xvi CONTENTS.
PAGti
IV. Diseases of the Spinal Nerves ....,...,. 1033
Cervical Plexus ............ 1033
Brachial Plexus ............ 1035
Lumbar and Sacral Plexuses ......... 1038
Sciatica 1039
G. General and Functional Diseases 1041
I. Acute Delirium (Bell's Mania) 1041
II. Paralysis Agitans 1042
Other Forms of Tremor 1044
III. Acute Chorea (Sydenham's Chorea; St. Vitus's Dance) .... 1045
IV. Other Affections described as Chorea 1053
V. Infantile Convulsions (Eclampsia) - 1056
VI. Epilepsy . 1058
VII. Migraine 1066
VIII. Neuralgia 1068
IX. Professional Spasms; Occupation Neuroses . • . . . . . 1072
X. Tetany 1074
XI. Hysteria 1076
XII. Neurasthenia 1086
XIII. The Traumatic Neuroses 1096
XIV. Other Forms of Functional Paralysis 1099
Periodical Paralysis 1099
Astasia; Abasia ............ 1099
H. Vaso-motor and Trophic Disorders .......... 1100
I. Raynaud's Disease ............ 1100
II. Erythromelalgia ............ 1102
III. Angio-neurotic (Edema ........... 1103
IV. Facial Hemiatrophy 1104
V. Acromegaly ............. 1105
Osteitis Deformans ........... 1106
Hypertrophic Pulmonary Arthropathy ....... 1107
Leontiasis Ossea 1107
Osteogenesis Imperfecta 1108
Achondroplasia (Chondrodystrophia Foetalis) ...... 1108
VI. Scleroderma 1109
Ainhum 1110
SECTION XI. DISEASES OF THE MUSCLES.
I. Myositis 1111
1112 1113 1113 1114
II. Myotonia (Thomsen's Disease)
III. Paramyoclonus Multiplex
IV. Myasthenia Gravis V. Amyotonia congenita (Oppenheim's Disease)
CHAETS AND ILLUSTEATIONS.
la. Malaria — Double Tertian Infection — Quotidian Fever ..... 18
lb. ^stivo-autumnal Infection — Remittent Fever . . . . . . .18
Ic. ^stivo-autumnal Fever — Quotidian Paroxysms . . . . . .19
Id. Quartan Fever 19
II. Typhoid Fever with Relapse ........... 73
III. Illustrating the Blood Changes in Typhoid Fever ...... 77
IV. Typhoid Fever — Haemorrhage from the Bowels* 81
V. Illustrating Influence of Baths in Typhoid Fever . . . . . . 101
VI. Relapsing Fever (after Murchison) Ill
VII. Small-pox (after Striimpell) 116
VIII. Scarlet Fever 133
IX. Measles 142
X. Temperature, Pulse, and Respiration Chart in Pneumonia .... 173
XL Showing Coincident Drop in the Fever and in the Leucocytes in Pneumonia. 178
XII. Chronic Tuberculosis, Two-hourly Chart for Three Days .... 328
XIII. Case of Sun-stroke treated with Ice-bath. Recovery. (Rectal Temperatures). 387
XIV. Showing LTric Acid and Phosphoric Acid Output in a Case of Acute Gout . 402 XV. Illustrating Influence of Diet on Sugar and Amount of LTrine in Diabetes . 422
XVI. Blood Chart, illustrating Ansemia in Purpura Haemorrhagica .... 720
XVII. Blood Chart, illustrating Chlorosis 723
XVIII. Blood Chart, illustrating Pernicious Ansemia 727
XIX. Blood Chart, illustrating Leukaemia 735
XX. Blood Chart, illustrating Rapid Production of Anaemia in Purpura Haem- orrhagica . 746
XXI. Diagrams after Martins, showing schematically the Power of the Heart
Muscle . . . .794
XXII. Schematic Division of the Phases of the Heart's Action (Martins) . . 796
1
2 3 4 5 6 7,8, 9 10
Diagram of Motor Path from Left Brain (Van Gehuchten) .... 869
Diagram of Motor Path (Van Gehuchten) 870
Diagram of Cerebral Localization 874
Diagram of Motor and Sensory Representation in the Internal Capsule . 875
Diagram of Motor and Sensory Paths in Crura 876
Diagram of Cross-section of Spinal Cord 876
Diagrams of Skin Areas corresponding to the Different Spinal Segments, 878, 879
Diagram of Motor Path from Left Brain 972
Diagram of Visual Paths (Vialet) 1011
* The red shows the two-hourly, the black the morning and evening temperature. 1 xvii
A TEXT-BOOK ON THE PRACTICE OF MEDICINE.
SECTION I.
DISEASES DUE TO ANIMAL PAEASITES.
A. DISEASES DUE TO PROTOZOA.
I. PSOROSPERMIASIS.
Under this term are embraced several affections produced by the spo- rozoa — also known as psorosperms and gregarinidae — parasites which are extraordinarily abundant in the invertebrates^, and are not uncommon in the higher mammals. Psorosperms are, as a rule, parasites of the cells — Cytozoa. The most suitable form for study is Coccidium oviforme of the rabbit, which produces a disease of the liver in which the organ is studded throughout with whitish nodules, ranging in size from a pin's head to a split pea. On section each nodule is seen to be a dilated portion of a bile-duct; the walls are lined with epithelium in the interior of which are multitudes of ovoid bodies — coc- cidia. Another very common form occurs in the muscles of the pig, the so-called Eainey's tube, which is an ovoid body within the sarcolemma contain- ing a number of small, sickle-shaped, unicellular organisms, Sarcocystis Mies- cheri. Another species, S. Jiominis, has been described in man.
Psorosperms do not play a very important role in human pathology.
1. Internal Psorospermiasis. — In a majority of the cases of this group the psorosperms have been found in the liver, producing a disease similar to that which occurs in rabbits. In Guebler's case there were tumors which could be felt during life, and they were determined by Leuckart to be due to coccidia. A patient of W. B. Haddon's was admitted to St. Thomas's Hospital with slight fever and drowsiness, and gradually became unconscious ; death occurring on the fourteenth day of observation. Whitish neoplasms were found upon the peritonaeum, omentum, and on the layers of the peri- cardium; and a few were found in the liver, spleen, and kidneys. A some- what similar case, though more remarkable, as it ran a very acute course, is reported by Silcott. A woman, aged fifty-three, admitted to St. Mary's Hos- pital, was thought to be suffering from typhoid fever. She had had a chill six weeks before admission. There were fever of an intermittent type, slight diarrhoea, nausea, tenderness over the liver and spleen, and a dry tongue; death occurred from heart-failure. The liver was enlarged, weighed 83 ounces, and in its substance there were caseous foci, around each of which was a ring of congestion. The spleen weighed 16 ounces and contained sim- 3 1
2 DISEASES DUE TO ANIMAL PARASITES.
ilar bodies. The ileum presented six papiile-like elevations. The masses resembled tubercles, but on examination coccidia were found.
The parasites are also found in the kidneys and ureters. Cases of this kind have been recorded by Bland Sutton and Paul Eve. In Eve's case the symptoms were liEematuria and frequent micturition, and death took place on the seventeenth day. The nodules throughout the pelvis and ureters have been regarded as mucous cysts.
2. Cutaneous Psorospermiasis. — The question of a protozoic dermatitis has been much discussed. The cases described by Gilchrist, Darier, Eixford, Montgomery, Ophiils, and others as dermatitis coccidoides have been shown to be due to a fungus allied to oidium, and the disease is now known as oidiomycosis. About 50 cases have been reported, nearly all from the Pacific coast of the United States. The relation of the disease to blastomycosis is still undetermined. The systemic forms of both have much in common — a chronic infectious process with multiple abscesses and nodules involving the skin, bones, joints, and internal organs, with symptoms simulating chronic tuberculosis or pyaemia.
II. AMCEBIC DYSENTERY.
Definition. — A colitis, acute or chronic, caused by the Amcebic dysen- terice. There is a special liability to the formation of abscess of the liver. A widely prevalent disease in Egypt, in India, and in tropical countries. It is the common variety of dysentery throughout the United States. It is endemic, the cases sometimes increasing to such an extent as to form an epi- demic. Sporadic instances apparently occur in all temperate regions. The relative frequency of this form of dysentery in the tropics is illustrated by the Manila statistics as given by Strong — of 1,328 cases in the United States Army, 561 were of the amoebic variety. The cases of acute and chronic dysen- tery in the Johns Hopkins Hospital have been almost exclusively amoebic. Futcher and Boggs have analyzed the cases to 1908. Of 182, 123 came from the State of Maryland, 171 were in males; 163 in whites to 19 in blacks.
Infection takes place from drinking contaminated water and by eating green vegetables, such as lettuce. Musgrave has grown amoebae from ice- cream used at receptions, etc.
Amceba Dysenteric. — The organism was first described by Lambl in 1859, and subsequently by Losch in 1875. It is placed by Leuckart in the Rhizopoda class of the Protozoa. Kartulius found them in the stools of the endemic dysentery in Egypt, and in the liver abscesses. In 1890 I found them in a case of dysentery with abscess of the liver originating in Panama. Sub- sequently from my wards a series of cases was described by Councilman and Lafleur. Since then numbers of observations have been made by Dock in the United States, by Quincke and Roos in Germany, and by many others. The little flakes of mucus or pus in the stools should be selected for examination or the mucus obtained by passing a soft-rubber catheter. Musgrave, on the other hand, holds that the best results are obtained by giving the patient a saline cathartic and examining the fluid portion of the stool. Students must learn to distinguish from amoebae the swollen, altered epithelial cells, which are round, with granular protoplasm.
DISEASES DUE TO PROTOZOA. 3
Amoeba or Entamoeba dysenterice is from fifteen to twenty ix in diameter, and consists of a clear outer zone (ectosarc), and a granular inner zone (endo- sarc), and contains a nucleus and one or two vacuoles. The movements are very similar to those of the ordinary amoeba, consisting of slight protrusions of the protoplasm. They vary a good deal, and usually may be intensified by having the slide heated. Not infrequently the amoebae contain red blood- corpuscles which they have included. In the tissues they are very readily recognized by suitable stains. They may be in enormous numbers, and some- times the field of the microscope is completely occupied by them. In the pus of a liver abscess they may be very abundant, though in large, long-stand- ing abscesses they may not be found until after a few days, when the pus begins to discharge from the wall of the abscess cavity. In the sputum in the cases of pulmono-hepatic abscess they are readily recognized.
Amoebae are frequently found in the stools of healthy persons, as Cunning- ham and Lewis pointed out. Schaudinn found them in from 20 to 60 per cent in Germany, but they vary greatly in different localities. Among 300 persons in Manila, Musgrave found 101 infected with amoebae, 61 of these had dysentery, the remaining 40 had no diarrhoea. In the next two months 8 of the 40 cases died and showed amoebic infection of the bowel. Within the next three months the remaining 32 had dysentery. Musgrave believes that at any time the amoeba may become pathogenic. Schaudinn described two distinct forms — a nonpathogenic Entamwbi coli, and a pathogenic larger form, the Entamoeba histolytica, the same as the Amoeba dysenterice, with a strongly refractile hyaline ectoplasm. The amoebae have been cultivated by Miller, Musgrave, Clegg, and others, but with difficulty, and it is doubtful if they grow apart from certain bacteria. Eesistant forms, somewhat anal- ogous to the gamete forms of the malarial parasite, have been described by Cunningham, Grassi and Calandruccio, and by Quincke. These "encysted amoebae ■ ' are believed to be necessary, under certain conditions, for the trans- mission of the disease from one person to another, and are regarded by Mus- grave and Clegg as the most dangerous forms of the organism. Cultures of amoebse have been shown to withstand drying for from eleven to fifteen months.
Morbid Anatomy. — The lesions are found in the large intestine, some- times in the lower portion of the ileum. Abscess of the liver is very common, and occurred in 37 of 182 cases at the Johns Hopkins Hospital.
Intestines. — The lesions consist of ulceration, produced by preceding infiltration, general or local, of the submucosa, due to an oedematous condition and to multiplication of the fixed cells of the tissue. In the earliest stage these local infiltrations appear as hemispherical elevations above the general level of the mucosa. The mucous membrane over these soon becomes necrotic and is cast off, exposing the infiltrated submucous tissue as a grayish-yellow gelatinous mass, which at first forms the floor of the ulcer, but is subsequently cast off as a slough.
The individual ulcers are round, oval, or irregular, with infiltrated, undermined edges. The visible aperture is often small compared to the loss of tissue beneath it, the ulcers undermining the mucosa, coalescing, and form- ing sinuous tracts bridged over by apparently normal mucous membrane. According to the stage at which the lesions are observed, the floor of the ulcer may be formed by the submucous, the muscular, or the serous coat of the
4 DISEASES DUE TO ANIMAL PARASITES.
intestine. Tlie ulceration may affect tlie whole or some portion only of the large intestine, particularly the cgecum, the hepatic and sigmoid flexures, and the rectum. In severe cases the whole of the intestine is much thickened and riddled with ulcers, with only here and there islands of intact mucous mem- brane. In 100 autopsies on this disease in Manila the appendix was involved in 7 ; perforation of the colon took place in 19.
The disease advances by progressive infiltration of the connective-tissue laj^ers of the intestine, which produces necrosis of the overlying structures. Thus, in severe cases there may be in different parts of the bowel sloughing en masse of the mucosa or of the muscularis, and the same process is observed, but not so conspicuously, in the less severe forms.
In some cases a secondary diphtheritic inflammation complicates the origi- nal lesions.
Healing takes place by the gradual formation of fibrous tissue in the floor and at the edges of the ulcers, which may ultimately result in partial and irregular strictures of the bowel.
Microscoj)ical examination shows a notable absence of the products of puru- lent inflammation. In the infiltrated tissues polynuclear leucocytes are sel- dom found, and never constitute purulent collections. On the other hand, there is proliferation of the fixed connective-tissue cells. Amoebee are found more or less abundantly in the tissues at the base of and around the ulcers, in the lymphatic spaces, and occasionally in the blood-vessels. The portal capillaries occasionally contain them, and this fact seems to afford the best explanation for the mode of infection of the liver.
The lesions in the livei' are of two kinds: first, local necroses of the parenchj^ma, scattered throughout the organ, and possibly due to the action of chemical products of the amoebas; and, secondly, abscesses. These may be single or multiple. There were 27 cases of hepatic abscess among the 119 cases of amoebic dysentery in my wards. Of these, 18 came to autopsy. In 10 the abscess was single and in 8 multiple. When single they are generally in the right lobe, either toward the convex surface near its diaphragmatic attachment, or on the concave surface in proximity to the bowel. Multiple abscesses are small and generally superficial. There may be innumerable miliary abscesses containing amoebse scattered throughout the entire liver. Although the hepatic abscess usualh" occurs within the first two months from the onset of the dysenterj'-, in one of my cases the latter had lasted one and in another six years. In 5 cases the intestinal symptoms had been so slight that dysentery had never been complained of. In 2 fatal cases there were only scars of old ulcers and in 2 others the mucosa appeared normal. In an early stage the abscesses are gra}ash-yellow, with sharpily defined contours, and con- tain a spongy necrotic material, with more or less fluid in its interstices. The larger abscesses have ragged necrotic walls, and contain a more or less viscid, greenish-3-ellow or reddish-yellow purulent material mixed with blood and shreds of liver-tissue. The older abscesses have fibrous walls of a dense, almost cartilaginous toughness. A section of the abscess wall shows an inner necrotic zone, a middle zone in which there is great proliferation of the con- nective-tissue cells and compression and atrophy of the liver-cells, and an outer zone of intense hypera^mia. There is the same absence of purulent inflam- mation as in the intestine, except in those cases in which a secondary infec-
DISEASES DUE TO PROTOZOA. 5
tion with p3'0genic organisms has taken place. Lesions in the kings are seen when an abscess of the liver — as so frequently happens — points toward the diaphragm and extends by continuity through it into the lower lobe of the right lung. This is the commonest situation for rupture to occur. Nine of my cases ruptured into the lung. In 3 cases rupture into the right pleura occurred, causing an empyema. In one of these the lung abscess ruptured into the pleura, producing a pyo-pneumothorax. Depending upon the situa-.. tion of the abscess, perforation may occur into other adjacent structures. In 3 of the cases perforation took place into the inferior vena cava and in another the upper pole of the right kidney had been invaded. The abscess may rupture into the pericardium, peritonseimi, stomach, intestine, portal and hepatic veins, or externally.*
Symptoms. — Differing remarkably in their symptoms, three groups of cases may be recognized :
Mild Form. — Infection may be present for a month or two before the individual is aware of it. There may be vague spnptoms — headache, lassitude, weakness, slight abdominal pains and occasional diarrhoea, features common enough in the tropics. Strong gives the case of one of his laboratory chemists who had slight diarrhoea for one day and asked to have the stools examined; an unusually rich infection with amoeba was found. The next day he felt well. From August to December 10th amcebge were present in the stools, though he had no s3anptoms. Liver abscess may occur in these cases.
Acute x4mcebic Dysentery. — Many cases have an acute onset. Pain and tenesmus are severe. The stools are bloody, or mucus and blood occur to- gether. In very severe cases there may be constant tenesmus, with pain of the greatest intensity, and the passage every few minutes of a little blood and mucus. In some cases large sloughs are passed. The temperature as a rule is not high. The patient may become rapidly emaciated; the heart's action becomes feeble, and death may occur within a week of the onset. Among the other symptoms to be mentioned are haemorrhage from the bowels, which occurred in three cases ; perforation of an ulcer, which occurred in three cases, with general peritonitis. While in a majority of the instances the patient recovers, in others the disease drags on and becomes chronic. In a few cases, after the separation of the sloughs, there is extensive ulceration remaining, with thickening and induration of the colon, and the patient has constant diarrhoea, loses weight, and ultimately dies exhausted, usually within three months of the onset. With the exception of cancer of the oesophagus and anorexia nervosa, no such extreme grade of emaciation is seen as in these cases. Extensive ulceration of the cornea may occur.
Chroxic Amcebic Dysentery. — The disease may be subacute from the onset, and gradually passes into a chronic stage, the special characteristic of which is alternating periods of constipation and of diarrhoea. These 'may occur over a period of from six months to a year or more. Some of our patients have been admitted to the hospital five or six times within a period of two years. During the exacerbations there are pain, frequent passages of mucus and blood, and a slight rise of temperature. Many of these patients do not feel very ill, and retain their nutrition in a remarkable way; indeed, in the United States it is rare to see the extreme emaciation so common in the * For a full account of Hepatic Abscess see Rolleston's work on Diseases of the Liver.
6 DISEASES DUE TO ANIMAL PARASITES.
chronic cases from the tropics. Alternating periods of improvement with attacks of diarrhoea are the rule. The appetite is capricious, the digestion disordered, and slight errors in diet are apt to be followed at once by an increase in the number of stools. The tongue is often red, glazed, and beefy. In protracted cases the emaciation may be extreme.
Complications and Sequelae. — Hepatic and hepato-pulmonary abscesses, the most frequent and serious complications, have already been dealt with. Perforation of the intestine and peritonitis occurred in three of my cases. Intestinal haemorrhage occurred three times. The infrequency of this com- plication is probably due to the thrombosis of the vessels about the areas of infiltration. Occasionally an arthritis, probably toxic in origin, may occur. There was one case in my series. Five cases were complicated by malaria; 1 by typhoid fever; 1 by pulmonary tuberculosis; and 1 by a strongyloides intestinalis infection.
Diagnosis. — From the other forms of dysenter}- the disease is recog- nized by the finding of amcebse in the stools. Unless one sees undoubted amoeboid movement a suspected body should not be considered an amoeba. A non-motile body containing one or more red cells is most probably an amoeba, but should only lead to further search for motile organisms. Swollen epithelial cells are confusing, but the hyaline periphery is not amoeboid in its action as is the ectosarc of the amoeba. The trichomonads and cerco- monads so frequently associated with amoebge are not likely to give trouble. The upper level of liver dulness should be watched throughout the course of a case. Any increase upward or downward should lead to the suspicion of a liver abscess. Hepatic abscess is usually accompanied by fever, sweats, or chills and local pain. It may be entirely latent. A varying leucocytosis occurs in the abscess cases. The highest count in my series was 53,000, the average being 18,350. The average leucocyte count in the uncomplicated dysentery cases was 10,600. Hepato-pulmonary abscess is attended by local lung signs and the expectoration of " anchovy sauce " sputum in which amoebse are almost invariably found.
Prognosis. — In many cases the disease yields to rest and intestinal medi- cation. Tendency to a relapse of the dysenteric symptoms is one of the strik- ing characteristics of the disease. One of my cases was admitted to the hospital five times in nine months. Of the 119 cases, 28, or 23.5 per cent, terminated fatally. That hepatic abscess is a serious complication is shown by the fact that of the 27 cases with this complication 19 died. Seventeen cases were operated on with 5 recoveries.
Treatment. — The disease is probably contracted in identically the same way as typhoid fever. Accordingly, the same prophylactic measures should be used. Eest in bed is very important and materially hastens recovery. The diet should be governed by the severity of the intestinal manifestations. In the very acute cases the patient should be given a liquid diet, consisting of milk, whey, and broths. Medicines administered internally yield, on the whole, very unsatisfactory results. Considering the fact that other bacteria are necessary for the growth of the amoeb£e in the intestine, Musgrave thinks that an effort should be made to limit the growth of the former by the admin- istration of intestinal antiseptics. None of these have proved very satisfac- tory, however, although Strong obtained good results with the use of aceto-
DISEASES DUE TO PROTOZOA. 7
zone administered by mouth and by enema. Bismuth probably does more harm than good owing to the fact that it coats the surface of the ulcers so that the solutions used in the injections can not reach the amoebae in the ulcer walls. Large injections of quinine solution in the strength of 1 to 5,000, gradually increasing to 1 to 2,500, and later to 1 to 1,000, have given most satisfactory results of all the remedies yet tried. The success of the treatment depends largely on the care with which the injections are given. The failures are undoubtedly, in many instances, due to the fact that sufficient care is not used to insure the solution reaching the caecum and ascending colon where the ulceration is often most severe. From a litre to two litres should be allowed to flow into the colon. The amoebae are rapidly destroyed by the drug. The patient's hips should be elevated and he should change his position so as to allow the fluid to flow into all parts of the colon. The solution should be retained, if possible, for fifteen minutes. These large injections, which Mus- grave also strongly advocates, are said not to be without a certain degree of danger. I have, however, never seen any ill effects, even with the very large amoiints. Two injections daily may be given. When there is much tenesmus a small injection of thin starch and half a drachm to a drachm of laudanum gives great relief; but for the tormina and tenesmus, the two most distressing symptoms, a hypodermic of morphia is the only satisfactory remedy. Local application to the abdomen, in the form of light poultices, or turpentine stupes are very grateful. Tuttle has recently reported good results in the treatment of amoebic dysentery by the use of simple ice-water enemas, given frequently. When medical treatment fails, colostomy may be tried or irrigations given through the appendix.
III. TRYPANOSOMIASIS.
Definition. — A chronic disorder characterized by fever, lassitude, weak- ness, wasting, and often a protracted lethargy — sleeping sickness. Trypano- soma gamhiense is the active agent in the disease.
History. — In 1843 Gruby found a blood parasite in the frog which he called Trypanosoma sanguinis. Subsequently it was found to be a very com- mon blood parasite in fishes and birds. In 1878 Lewis found it in the rat — T. lewisii — in which it apparently does no harm. The pathological signifi- cance of the protozoa was first suggested in 1880 by Griffith Evans, who discov- ered trypanosomes — T. evansii — in the disease of horses and cattle in India known as snrra. Unfortunately, as my good friend Evans often complained to me, but little attention was paid to this really radical discovery — not even the subsequent studies of Laveran on malaria and of Theobald Smith on Texas fever stirred workers to a recognition of the place of the protozoa as pathogenic agents. In 1895 Bruce made the important announcement that the tsetze fly disease or nagana of South Africa, which made whole districts impassable for cattle and horses, was really due to a trypanosome — T. hrucei. Normally present in the blood of the big-game animals of the districts, and doing them no harm, it was conveyed by the tsetze fly to the non-immune horses and cattle imported into what were called the fly-belts. Other trypanosomes are the Philippine surra, studied by Musgrave, the mal de caderas — T. equi-
8 DISEASES DUE TO ANIMAL PARASITES.
num — of South America and a harmless infection in cattle in the Transvaal caused by Trypanosoma theileri.
Human Trypanosomiasis. — In 1901 Button found a trypanosome in the blood of a West Indian. In 1903 Castellani found trypanosomes in the cere- bro-spinal fluid and in the blood of five cases of the African sleeping sickness. The Eoyal Society Commission (Bruce and Nabarro) demonstrated the great frequency of the parasites in the cerebro-spinal fluid and in the blood in sleep- ing sickness, and suggested that it was a sort of human tsetze fly infection.
Distribution". — For many years it had been kno-wTi that the West African natives were subject to a remarkable malady known as the lethargy or sleeping sickness. It was also met with among the slaves imported into America. The demonstration of the association of the trypanosomes with the terrible sleeping sickness has been the most important recent " find " in tropical medicine. The disease prevails in Gambia, Sierra Leone, and Liberia, and is spreading rapidly in the Congo basin, Uganda, and Ehodesia. The recent opening up of equa- torial Africa has led to intercommunication between the different districts which were formerly isolated, and the seriousness of the disease may be appre- ciated from the fact that within three years after its introduction 100,000 negroes died of it in Uganda. The parasites may be present in the blood for a long time, at least without causing any symptoms. Bruce found them in 23 out of 80 apparently healthy natives, and Button, Todd, and Christy in 103 out of 1,172 persons examined.
The disease is not confuied to negroes, and several Europeans have been attacked. Persons particularly prone are those who live on the wooded shores of the lakes and rivers, such as fishermen and canoe men.
The parasite is introduced by the bite of a fly, the Glossina palpalis, and where this insect exists the disease is liable to prevail. The fly lives on the bushes on the lake shores or river banks, and feeds on the blood of crocodiles, antelopes, etc. It is possible that the trypanosomes undergo a development in the body of the fly. Koch states that the disease may be conveyed to women in coition.
Symptoms. — There is stated to be a long latent period. The Uganda Com- missioners divide the course of the disease into three stages: first, of fever with rapid pulse, dulling of the mind, and loss of weight; secondly, the stage of tremors in which the gait becomes shuffling, the speech slow, and there are tremors of the tongue and of the hands and feet; lastly, a stage in which the patient becomes lethargic with low temperature and presents the typical picture of the dreaded sleeping sickness. The parasites are found in the cerebro-spinal fluid, less constantly in the blood. In the early stages the glands of the neck are involved, and Todd and Button recommend puncture of these glands for the purpose, of diagnosis. Beath is usually caused by some intercurrent infec- tion, as purulent meningitis or suppuration of the lymph glands. The dura- tion is seldom longer than eighteen months. Europeans are not often attacked. To stay the ravages and prevent the spread of the disease will tax the energies of the nations interested in the settlement of tropical Africa. The hope appears to be in the extermination of the animals upon which the Glossina palpalis feeds (among which Koch holds the crocodile to be the most impor- tant), just as the killing off of the big game in other parts of iVfrica has saved the cattle from the ravages of the tsetze fly.
DISEASES DUE TO PROTOZOA. 9
Wolferstan Thomas and Breinl introduced the atoxyl treatment, and Boyce recommends the subsequent use of bichloride of mercury. Koch's re- port on the atoxyl treatment is most encouraging; 0.5 gramme is injected on two successive days, and repeated at intervals of ten days. A few cases have been cured. As prophylactic measures, segregation and prohibition of immigration from infected areas should be carried out. The work of Laveran and Mesnil, recently translated and edited by Nabarro, is the standard author- ity on the disease.
IV. TROPICAL SPLENOMEGALY— Tropical Cachexia.
(Piroplasmosis — Dum-Dum Fever — Kala-Azar.)
Definition. — A chronic disease of tropical and sub-tropical countries, characterized by enlarged spleen, anaemia, irregularly remittent fever, asso- ciated with the presence of a protozoon parasite of the piroplasma type.
In 1900 Leishman discovered the parasites in the spleen. Cunningham had described similar bodies in the Delhi boil. In 1903 Donovan's inde- pendent observations stimulated active work on the subject, and the careful studies of Eogers, Christophers, Philips, and Bentley have established the clinical and anatomical identity of one form of tropical cachexial fever. Musgrave and Woolley have shown that in the Philippines there is a form of tropical splenomegaly not associated with the Leishman-Donovan body.
Distribution. — The disease is widely prevalent and almost uniformly fatal in India, Assam, Ceylon, China, and Egypt. Europeans are rarely attacked.
The Parasite. — Most abundant in the spleen, it has been found also in the bone-marrow, the mesenteric glands, the liver, in the intestinal ulcers, but not in the circulating blood. Seen in smears of the spleen juice stained by Eomanowsky's method, there are oat-shaped, oval and circular bodies, with a spherical nucleus close against the capsule, and a short, rod-like body on the opposite side. Two of these bodies may be closely applied to each other, and groups of them, from ten to fifty, may be arranged in a rosette. Eogers has cultivated a trypanosoma-like body from these forms, and Patton has traced its extra-corporeal development in the bed-bug.
Symptoms. — The following succinct description is given by Leishman:
" Splenic and hepatic enlargement — the former being apparently constant, while the latter is common but not invariable. A peculiar earthy pallor of the skin, and, in the advanced stages, an intense degree of emaciation and muscular atrophy. A long-continued, irregularly remittent fever, of no defi- nite type, lasting frequently for many months, with or without remissions. Hsemorrhages, such as epistaxis, bleeding from the gums, subcutaneous haem- orrhages or purpuric eruptions. Transitory cedemas of various regions or of the limbs." The anaemia is not excessive, rarely below 2,000,000 per c.mm., with a marked leucopenia and a relative increase in the lymphocytes and large mononuclears. The diagnosis rests upon the detection of the parasites in the blood obtained by puncture from the spleen or liver, preferably the latter.
In a few cases the disease runs an acute course — from four to five months, and toward the end the parasites are found in the peripheral blood. The disease is very fully considered in Eogers' work " On Tropical Diseases." 3
10 DISEASES DUE TO ANIMAL PARASITES.
Prophylaxis. — Leonard Eogers and Price have shown that Jcala-azar can be eradicated from infected Coolie lines in Assam by segregation, and this points to the measures which are likely to be successful in India and Africa.
Treatment. — While quinine is not a specific, as in malaria, it seems to reduce the fever. Iron, arsenic, and tonics are helpful in the anemia. The atoxyl treatment may be tried.
V. MALARIAL FEVER.
Definition. — An infectious disease characterized by: (a) paroxysms of intermittent fever of quotidian, tertian, or quartan type; (&) a continued fever with marked remissions; (c) certain pernicious, rapidly fatal forms; and (d) a chronic cachexia, with anaemia and an enlarged spleen.
With the disease are invariably associated the hamocytozoa described by Laveran, which are transmitted to man by the bite of the mosquito.
Etiology. — (1) Geographical Distribution. — In Europe, southern Eus- sia and certain parts of Italy are now the chief seats of the disease. It is rare in Germany, France, and England, and the foci of epidemics are becoming yearly more restricted. In the United States malaria has progressively dimin- ished in extent and severity during the past fifty years. Erom New England, where it once prevailed extensively, it has gradually disappeared, but there has of late years been a slight return in some places. In the city of New York the milder forms of the disease are not uncommon. In Philadelphia and along the valleys of the Delaware and Schuylkill Elvers, formerly hot-beds of malaria, the disease has become much restricted. In Baltimore a few cases occur in the autumn, but a majority of the patients seeking relief are from the outlying districts and one or two of the inlets of Chesapeake Bay. Throughout the Southern States there are many regions in which malaria prevails ; but here, too, the disease has diminished in prevalence and intensity. In the Northwestern States malaria is almost unknown. It is rare on the Pacific coast. In the region of the Great Lakes malaria prevails only in the Lake Erie and Lake St. Clair regions. The St. Lawrence basin remains free from the disease.
In India malaria is very prevalent, particularly in the great river basins. In Burma and Assam severe types are met with. In Africa the malarial fevers form the great obstacle to European settlements on the coast and along the river basins. The hlack-water or West African fever of the Gold Coast is a very fatal type of malarial ha^moglobinuria. In the Canal Zone, Panama, in 1907 the incidence of the disease was reduced one-half compared with 1906.
(2) Season. — In the tropics there are minimal and maximal periods, the former corresponding to the summer and winter, the latter to the spring and autumn months. In temperate regions, like the central Atlantic States, there are only a few cases in the spring, usually in the month of May, and a large number of cases in September and October, and sometimes in November.
(3) The Parasite. — Parasites of the red blood-corpuscles — hsemocytozoa — are very widespread throughout the animal series. They are met with in the blood of frogs, fish, birds, and among mammals in monkeys, bats, cattle, and man. In birds and in frogs the parasites appear to do no harm except when present in very large numbers.
DISEASES DUE TO PROTOZOA. 11
In 1880 Laveran, a French army surgeon stationed at Algiers, noted in the blood of patients with malarial fever pigmented bodies, which he regarded as parasites, and as the cause of the disease, Richard, another French army surgeon, confirmed these observations. In 1885 Marchiafava and Celli described the parasites with great accuracy, and in the same year Golgi made the all-important observation that the paroxysm of fever invariably coincided with the sporulation or segmentation of a group of the parasites. In the fol- lowing year (1886) Laveran's observations were brought before the profession of the United States by Sternberg. Councilman and Abbott had already, in the previous year, described the remarkable pigmented bodies in the red blood- corpuscles in the blood-vessels of the brain in a fatal case, and in 1886 Coun- cilman confirmed the observations of Laveran in clinical cases. Stimulated by his work, I began studying the malarial cases in the Philadelphia Hospital, and soon became convinced of the truth of Laveran's discovery, and was able to confirm Golgi's statement as to the coincidence of the sporulation with the paroxysm. The work was taken up actively in the United States by Walter James, Dock, Koplik, Thayer, Hewetson, and others, and in a number of sub- sequent communications I tried to emphasize the extraordinary clinical importance of Laveran's discovery.*
Among British observers, Vandyke Carter alone, in India, seems to have appreciated at an early date the profound significance of Laveran's work.
The next important observation was the discovery by Golgi that the para- site of quartan malarial fever was different from the tertian. From this time on the Italian observers took up the work with great energy, and in 1889 Marchiafava and Celli determined that the organism of the severer forms of malarial fever differed from the parasite of the tertian and quartan varieties. During the past ten years the work of observers in many lands has confirmed these essential features, and has added greatly to our knowledge of the struc- ture and modes of development of the parasites.
The next important step related to the question of the mode of infec- tion. It had been suggested by King, of Washington, and others, that the disease was transmitted by the mosquitoes. The important role played by insects as an intermediate host had been shown in the case of the Texas cattle fever, in which Theobald Smith demonstrated that the hgematozoa developed in, and the disease was transmitted by, ticks; but it remained for Manson to formulate in a clear and scientific way the theory of infec- tion in malaria by the mosquito. Impressed with the truth of this, Ross studied the problem in India, and showed that the parasites developed in the bodies of the mosquitoes, demonstrating conclusively that the infection in birds was transmitted by the mosquito. W. G, MacCallum suggested that
* The following references to work on malaria which has been done in connection with my clinic, chiefly under the supervision of my colleague, Professor Thayer, may be of in- terest : Philadelphia Medical Times, 1886 ; British Medical Journal, March, 1887 ; Medical News, 1889, vol, i ; Johns Hopkins Hospital Bulletin, 1889 ; the first edition of my Text- Book of Medicine, 1892; Thayer and Hewetson, Johns Hopkins Hospital Reports, 1895; Thayer Lectures on Malarial Fever, 1897; W, G. MacCallum, Hsematozoa of Birds, Jour, of Exp. Med., 1898 ; Opie, on the HaBmatozoa of Birds, 1898 ; Barker, on Fatal Cases of Malaria, Johns Hopkins Hospital Reports, 1899: MacCallum, on the Significance of the Flagella, Lancet, 1897; Thayer, Transactions American Medical Congress, vol. iv, 1900; Lazear, Structure of the Malarial Parasites, Johns Hopkins Hospital Reports, 1902.
12 DISEASES DUE TO ANIMAL PARASITES.
the flagella were sexual elements, and observed the process of fertilization by them. Studies by Grassi, Bastianelli and Bignami, and man} others, con- firmed the observations of Eoss and demonstrated the fact that the malarial parasites of human beings develop only in mosquitoes of the genus anopheles.
Then came the practical demonstration by Italian observers, and by the interesting experiments on Manson, Jr., of the direct transmission of the disease to man by the bite of infected mosquitoes. And lastly, as a practical conclusion of the whole matter, the results of the antimalarial campaign in Italy and of the remarkable experiments of Koch and his assistants have shown that by protecting the individual from the bites of mosquitoes, by exterminating the insect, or by carefully treating all patients so that no opportunity may be offered for the parasite to enter the mosquito, malaria may be eradicated from any locality.
General Morphology of the Parasite. — Belonging to the sporozoa, it has received a, large number of names. The term Plasmodium, inapt though it may be, must, according to the rules of zoological nomenclature, be applied to the human parasite. There are three well-marked varieties of the para- site, which exist in two separate phases or stages: (a) the parasite in man who acts as the intermediate host, and in whom, in the cycle of its develop- ment, it causes symptoms of malaria; and (&) an extracorporeal cycle, in which it lives and develops in the body of the mosquito, which is its definitive host.
I. The Parasite in Man. — (a) The Parasite of Tertian Fever (Plas- modium vivax). — The earliest form seen in the red blood-corpuscle is round or irregular in shape, about 2 ft in diameter and unpigmented. It corresponds very much in appearance with the segments of the rosettes formed during the chill. A few hours later the body has increased in size, is still ring-shaped, and there is pigment in the form of fine grains. It has a relatively large nuclear body, consisting of a well-defined, clear area, in part almost transpar- ent, in part consisting of a milk-white substance, in which there lies a small, deeply staining chromatin mass, as shown by Eomanowsk}'''s method of stain- ing. At this period it usually shows active amoeboid movements, with tongue- like protrusions. The pigment increases in amount and the corpuscle becomes larger and paler, owing to a progressive diminution of its hsemoglobin. There is a gradual growth of the parasite, which, toward the end of forty-eight hours, occupies almost all of the swollen red corpuscle. It is now much pigmented, and is in the stage of what is often called the full-grown parasite. Between the fortieth and forty-eighth hours many of the parasites are seen to have undergone the remarkable change known as segmentation, in which the pigment becomes collected into a single mass or block, and the proto- plasm divides into a series of from fifteen to twenty spores, often showing a radial arrangement. Certain full-grown tertian parasites, however, do not undergo segmentation. These forms, which are larger than the sporulating bodies, and contain very actively dancing pigment granules, represent the sexually differentiated form of the parasite — gametocytes.
(&) The Parasite of Quartan Fever {Plasmodium malarice). — The earliest form is very like the tertian in appearance, but as it increases in size the earlier granules are coarser and darker and the movement is not nearly so marked. By the second day the parasite is still larger, rounded in shape^
DISEASES DUE TO PROTOZOA. 13
scarcely at all amoeboid, and the pigment is more often arranged at the periph- ery of the parasite. The rim of protoplasm about it is often of a deep yel- lowish-green color or of a dark brassy tint. On the third day the segment- ing bodies become abundant, the pigment flowing in toward the centre of the parasite in radial lines so as to give a star-shaped appearance. The parasites finally break up into from six to twelve segments. Here also, as in the case of the tertian parasite, some full-grown bodies persist without sporulating, representing the gametocytes.
(c) The Parasite of the /Estivo- Autumnal Fever {Plasmodium, prcecox) is considerably smaller than the other varieties ; at full development it is often less than one half the size of a red blood-corpuscle. The pigment is much scantier, often consisting of a few minute granules. At first only the earlier stages of development, small, hyaline bodies, sometimes with one or two pig- ment granules, are to be found in the peripheral circulation; the later stages are ordinarily to be seen only in the blood of certain internal organs, the spleen and bone marrow particularly. The corpuscles containing the parasites become not infrequently shrunken, crenated, and brassy-colored. After the process has existed for about a week, larger, refractive, crescentic, ovoid, and round bodies, with central clumps of coarse pigment granules, begin to appear. These bodies are characteristic of aestivo-autumnal fever. The crescentic and ovoid forms are incapable of sporulation; they are analogous to the large, full-grown, non-sporulating bodies of the tertian and quartan parasites which have been mentioned above, and represent sexually differentiated forms — gametocytes. Within the human host they are incapable of further develop- ment, but upon the slide, or within the stomach of the normal intermediate host, the mosquito, the male elements (micro-gametocytes) give rise to a num- ber of long, actively motile flagella (micro-gametes) which break loose, pene- trating and fecundating the female forms — macro-gametes (W. G-. Mac- Callum). The fecundated female form enters into the stomach wall of the intermediate host, the mosquito, where it undergoes a definite cycle of existence.
II. The Parasite within the Body of the Mosquito. — The brilliant re- searches of Eoss, followed by the work of Grassi, Bastianelli, Bignami, Stephens, Christophers, and Daniels, have proved that a certain genus of mosquito — anopheles — is not only the intermediate host of the malarial para- site, but also the sole source of infection. In the present state of our knowl- edge it would appear that all species of the genus anopheles may act as hosts of the parasite. The more common genera of mosquito in temperate cli- mates are culex and anopheles. The different species of culex form the great majority of our ordinary house mosquitoes, and are apparently incapable of acting as hosts of the malarial parasite. All malarial regions, however, which have been investigated contain anopheles. Although this is appar- ently a positive rule, anopheles may, however, be present without the exist- ence of malaria under two circumstances: first, when the climate is too' cold for the development of the malarial parasite ; and secondly, in a region which has not yet been infected. So far as is known, the parasite exists only in the mosquito and in man. It is apparently fair to state that regions in which mosquitoes of the genus anopheles are present may become malarious during the warm season.
14 DISEASES DUE TO ANIMAL PARASITES.
A large number of species of anopheles have been described. In Xorth America, however, only four have been positively recognized: A. 'punctlpeiinis (Say), A. maculipennis (Wied), A. crucians (Wied), A. argyritarsis (Desv.). The commonest variety, and that which in all probability is most concerned in the spread of the disease, is A. maculipennis, which is, also, the most impor- tant agent in the spread of the disease on the Continent.
The palpi in the mature culex are extremely short, only to be seen on careful observation at the base of the proboscis, while in the anopheles they are nearly of equal length with the proboscis, so that on superficial observa- tion the insect would appear to have three proboscides. The wings of the common species of culex show no markings beyond the ordinary veins. The wings of all the x4.merican species of anopheles show distinct mottling. The culex, when sitting upon the wall or ceiling, holds its posterior pair of legs turned up above its back, while the body lies nearly parallel to the wall. In some instances, when it is full of blood, and sitting upon the ceiling, the body may sag downward considerably. The anopheles, when sitting upon the wall or ceiling, holds its posterior pair of legs commonly either against the wall or hanging downward, though in some instances they may be lifted above the back. The body, however, instead of lying parallel to the wall or ceiling, protrudes at an angle of 45° or more. These simple points are sufficient to permit the ready distinction of species by almost any individual.
The culex lays its eggs in sinks, tanks, cisterns, and any collection of water about or in houses, while anopheles lays its eggs in small, shallow pud- dles or slowly running streams, especially those in which certain forms of algae exist. The culex is essentially a city mosquito, the anopheles a country insect.
Evolution in the Body of the Mosquito. — When a mosquito of the genus anopheles bites an individual whose blood contains sex-ripe forms (gameto- cytes) of the malarial parasite, flagellation and fecundation of the female element occurs within the stomach of the insect. The fecundated element then penetrates the wall of the mosquito's stomach and begins a definite cycle of development in the muscular coat. Two days after biting there begin to appear small, round, refractive, granular bodies in the stomach wall of the mosquito, which contain pigment granules clearly identical with those pre- viously contained in the malarial parasite. These develop until at the end of seven days they have reached a diameter of from 60 to 70 fi. At this period they may be observed to show a delicate radial striation due to the presence of great numbers of small sporoblasts. The mother oocyst (z5'gote) then bursts, setting free into the body cavity of the mosquito an enormous number of delicate spindle-shaped sporozoids. These accumulate in the cells of the veneno-salivary glands of the mosquito, and, escaping into the ducts, are inoculated with subsequent bites of the insect. These little spindle-shaped sporozoids develop, after inoculation into the warm-blooded host, into fresh young parasites. The sporozoid which has developed in the oocyst in the stomach wall of the mosquito is then the equivalent of the spore resulting from the asexual segmentation of the full-grown parasite in the circulation. Either one, on entering a red blood-corpuscle, may give rise to the asexual or sexual cycle. As a rule the first several generations of parasites in the human body pursue the asexual cycle, the sexual forms developing later.
DISEASES DUE TO PROTOZOA. 15
These sexual forms, sterile while in the human host, serve as the means of preserving the life of the parasite and spreading infection when the individual is subjected to bites of anopheles.
Mr. Howard, of the Entomological Department at Washington, has issued a very useful pamphlet on the varieties and the methods of identification of the mosquito. In Africa the distribution of the forms has been studied by Stephens, Christophers, and Daniels. To those interested in the subject, Christophers' careful study of the Anatomy and Histology of the Adult Female Mosquito (Report of Malaria Committee, Royal Society, No. IV) will prove of great help. The Royal Society Reports (Malaria Committee) and the Studies of the Liverpool School may be consulted for technical details and for valuable information relating to tropical malaria.
Morbid Anatomy. — The changes result from the disintegration of the red blood-corpuscles, accumulation of the pigment thereby formed, and possibly the influence of toxic materials produced by the parasite. Cases of simple malarial infection, the ague, are rarely fatal, and our knowledge of the morbid anatomy of the disease is drawn from the pernicious malaria or the chronic cachexia. Rupture of the enlarged spleen may occur spon- taneously, but more commonly from trauma. A case of the kind was admitted under my colleague, Halsted, in June, 1889, and Dock has reported two cases. I have known fatal haemorrhage to follow the exploratory punc- ture of an enlarged malarial spleen.
(1) Pernicious Malaeia. — The blood is hydremic and the serum may even be tinged with haemoglobin. The red blood-corpuscles present the endoglobular forms of the parasite and are in all stages of destruction. The spleen is enlarged, often only moderately; thus, of two fatal cases in my wards the spleens measured 13 X 8 cm. and 14 X 8 cm. respec- tively. In a fresh infection, the spleen is usually very soft, and the pulp lake-colored and turbid. The liver is swollen and turbid.
In some acute pernicious cases with choleraic symptoms, the capillaries of the gastro-intestinal mucosa may be packed with parasites.
(2) Malarial Cachexia. — In fatal cases of chronic paludism death occurs usually from anaemia or the haemorrhage associated with it.
The anaemia is profound, particularly if the patient has died of fever. The spleen is greatly enlarged, and may weigh from seven to ten pounds.
The liver may be greatly enlarged, and presents to the naked eye a grayish-brown or slate color, due to the large amount of pigment. In the portal canals and beneath the capsule the connective tissue is impregnated with melanin. The pigment is seen in the Kupffer's cells and the perivascu- lar tissue.
The kidneys may be enlarged and present a grayish-red color, or areas of pigmentation may be seen. The peritonaeum is usually of a deep slate color. The mucous membrane of the stomach and intestines may have the same hue, due to the pigment in and about the blood-vessels. In some cases this is con- fined to the lymph nodules of Peyer's patches, causing the shaven-beard appearance.
(3) The Accidental and Late Lesions of Malarial Fever. — (a) The Liver. — Paludal hepatitis plays a very important role in the history of malaria, as described by French writers. Only those cases in which the his-
16 DISEASES DUE TO ANIMAL PARASITES.
tory of chronic malaria is definite, and in which the melanosis of both liver and spleen coexist, should be regarded as of paludal origin.
(h) Pneumonia is believed by many authors to be common in malaria, and even to depend directly upon the malarial poison, occurring either in the acute or in the chronic forms of the disease. I have no personal knowledge of such a special pneumonia.
(c) Nephritis. — Moderate albuminuria is a frequent occurrence, having occurred in 46.4 per cent of the cases in my wards. Acute nephritis is rela- tively frequent in aestivo-autumnal infections, having occurred in over 4.5 per cent of my cases. Chronic nephritis occasionally follows long-continued or frequently repeated infections.
Clinical Forms of Malarial Fever. — (1) The Regularly Inteemittent Fevees. — (a) Tertian fever; (6) quartan fever. These forms are charac- terized by recurring paroxysms of what are knoAVQ as ague, in which, as a rule, chill, fever, and sweat follow each other in orderly* sequence. The stage of iiicubation is not definitely known; it probably varies much accord- ing to the amount of the infectious material absorbed. Experimentally the period of incubation varies from thirty-six hours to fifteen days, being a trifle longer in quartan than in tertian infections. Attacks have been reported within a very short time after the apparent exposure. On the other hand, the ague may be, as is said, " in the system," and the patient may have a paroxysm months after he has removed from a malarial region, though of course this can not be the case unless he has had the disease when living there.
Description of the Paroxysm. — The patient generally knows he is going to have a chill a few hours before its advent by unpleasant feelings and uneasy sensations, sometimes by headache. The paroxysm is divided into three stages — cold, hot, and sweating.
Cold Stage. — The onset is indicated by a feeling of lassitude and a desire to yawn and stretch, by headache, uneasy sensations in the epigastrium, some- times by nausea and vomiting. Even before the chill begins the thermometer indicates some rise in temperature. Gradually the patient begins to shiver, the face looks cold, and in the fully developed rigor the whole body shakes, the teeth chatter, and the movements may often be violent enough to shake the bed. I^ot only does the patient look cold and blue, but a surface ther- mometer will indicate a reduction of the skin temperature. On the other hand, the axillary or rectal temperature may, during the chill, be greatly increased, and, as shown in the chart, the fever may rise meanwhile even to 105° or 106°. Of symptoms associated with the chill, nausea and vomiting are common. There may be intense headache. The pulse is quick, small, and hard. The urine is increased in quantity. The chill lasts for a variable time, from ten or twelve minutes to an hour, or even longer.
The hot stage is ushered in by transient flushes of heat; gradually the coldness of the surface disappears and the skin becomes intensely hot. The contrast in the patient's appearance is striking: the face is flushed, the hands are congested, the skin is reddened, the pulse is full and bounding, the heart's action is forcible, and the patient may complain of a throbbing head- ache. There may be active delirium. One of my patients in this stage jumped through a ward window and sustained fatal injuries. The rectal temperature may not increase much during this stage; in fact, by the termi"
DISEASES DUE TO PROTOZOA. 17
nation of the chill the fever may have reached its maximum. The duration of the hot stage varies from half an hour to three or four hours. The patient is intensely thirsty and drinks eagerly of cold water.
Sweating Stage. — Beads of perspiration appear upon the face and grad- ually the entire body is bathed in a copious sweat. The uncomfortable feel- ing associated with the fever disappears, the headache is relieved, and within an hour or two the paroxysm is over and the patient usually sinks into a refreshing sleep. The sweating varies much. It may be drenching in char- acter or it may be slight.
Chart la is from a case of double tertian infection with resulting quotidian paroxysms. Charts I& and Ic give temperature curves in aestivo-autumnal forms. Chart Id shows a quartan ague.
The total duration of the paroxysm averages from ten to twelve hours, but may be shorter. Variations in the paroxysm are common. Thus the patient may, instead of a chill, experience only a slight feeling of coldness. The most common variation is the occurrence of a hot stage alone, or with very slight sweating. During the paroxysm the spleen is enlarged and the edge can usu- ally be felt below the costal margin. In the interval or intermission of the paroxysm the patient feels very well, and, unless the disease is unusually severe, he is able to be up. Bronchitis is a common symptom. Herpes, usu- ally labial, is almost as frequent in ague as in pneumonia.
Types of the Regularly Intermittent Fevers. — As has been stated in the description of the parasites, two distinct types of the regularly intermit- tent fevers have been separated. These are (a) tertian fever and (&) quartan fever.
(a) Tertian Fever. — This type of fever depends upon the presence in the blood of the tertian parasite, an organism which, as stated above, is usually pi-esent in sharply defined groups, whose cycle of development lasts approx- imately forty-eight hours, segmentation occurring every third day. In infections with one group of the tertian parasite the paroxysms occur syn- chronously with segmentation at remarkably regular intervals of about forty- eight hours, every third day — hence the name tertian. Very commonly, however, there may be two groups of parasites which reach maturity on alter- nate days, resulting thus in daily (quotidian) paroxysms — douMe tertian infection. Quotidian fever, depending upon double tertian infection, is the most frequent type in the acute intermittent fevers in this latitude.
(&) Quartan Fever. — This type of fever depends upon infection with the quartan parasite, an organism which occurs in well-defined groups, whose cycle of existence lasts about seventy-two hours. In infection with one group of parasites the paroxysm occurs every fourth day; hence the term qu/irtan. At times, however, two groups of the parasites may be present; under these circumstances paroxysms occur on two successive days, with a day of inter- mission following. In infection with three groups of parasites there are daily paroxysms.
Thus a quotidian intermittent fever may be due to infection with either the tertian or quartan parasites.
Course of the Disease. — After a few paroxysms, or after the disease has persisted for ten days or two "weeks, the patient may get well without any special medication, I have repeatedly known the chills to stop spontane-
18
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DISEASES DUE TO PROTOZOA.
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Chart Ic. — ^stivo-Autumnal Fever. — Quotidian Paroxysms.
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July 19 20 21 22 23 21 | |
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2P.M. 4P.M. 8 P.M. lOP.M. t2M. 2A.M. 4A.M. 6A.M. 8 A.M. 10A.M. 12 N. 2 P.M. 4P,M. 6P.M. 8 P.M. 12M. 2A.M. 4A.M. 6A.M. 8 A.M. 10A.M. 12 N. 2P.M 4P.M. 6P.M. ep.M. 10P.M. 12M. 2A.M. 4 A.M. 6A.M. 8 A.M. 10A.M. 2 P.M. 4 P.M. 6P.M. ep.M. 10P.M. 12M. 2A.M. 4 A.M. 6 A.M. eA.M. 10A.M. 12 N. 2 P.M. 4 P.M. 6P.M. 8 P.M. 10P.M. 12M. 2A.M. 4A.M. 6 A.M. 8 AM. 10A.M. 12 N. 2 P.M. 4P M. 6P.M. 8 P.M. 10P.M. 12M. |
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Chart Id. — Quartan Fever.
20 DISEASES DUE TO ANIMAL PARASITES.
ously. Eelapses are common. The infection may persist for years, and an attack may follow an accident^, an acute fever, or a surgical operation. A rest- ing stage of the parasite has been suggested in explanation of these long inter- vals. Persistence of the fever leads to aneemia and haematogenous jaundice, owing to the destruction of the blood-disks. Ultimately the condition may become chronic — malarial cachexia.
(2) The more Irregular, Eemittent, or Continued Fevers. — 2Estivo- autumnal Fever. — This type of fever occurs in temperate climates, chiefly in the later summer and autumn ; hence the term given to it by Marchiaf ava and Celli, cestivo-autumnal fever. The severer forms of it prevail in the Southern States and in tropical countries.
This type of fever is associated with the presence in the blood of the Eestivo-autumnal parasite, an organism the length of whose cycle of develop- ment, ordinarily about forty-eight hours, is probably subject to considerable variations, while the existence of multiple groups of the parasite, or the absence of arrangement into definite groups, is not infrequent.
The symptoms are therefore, as might be expected, often irregular. In some instances there may be regular intermittent fever occurring at uncer- tain intervals of from twenty-four to forty-eight hours, or even more. In the cases with longer remissions the paroxysms are longer. Some of the quotidian intermittent cases may closely resemble the quotidian fever depend- ing upon double tertian or triple quartan infection. Commonly, however, the paroxysms show material differences; their length averages over twenty hours, instead of from ten or twelve; the onset occurs often without chills and even without chilly sensations. The rise in temperature is frequently gradual and slow, instead of sudden, while the fall may occur by lysis instead of by crisis. There may be a marked tendency toward anticipation in the paroxysms, while frequently, from the anticipation of one paroxysm or the retardation of another, more or less continuous fever may result. Some- times there is continuous fever without sharp paroxysms. In these cases of continuous and remittent fever the patient, seen fairly early in the disease, has a flushed face and looks ill. The tongue is furred, the pulse is full and bounding, but rarely dicrotic. The temperature may range from 103° to 103°, or is in some instances higher. The general appearance of the patient is strongly suggestive of typhoid fever — a suggestion still further borne out by the existence of acute splenic enlargement of moderate grade. As in intermittent fever, an initial bronchitis may be present. The course of these cases is variable. The fever may be continuous, with remissions more or less marked; definite paroxysms with or without chills may occur, in which the temperature rises to 105° or 106°. Intestinal symptoms are usually absent. A slight hsematogenous jaundice may arise early. Delirium of a mild type may occur. The cases vary very greatly in severity. In some the fever subsides at the end of the week, and the practitioner is in doubt whether he has had to do with a mild typhoid or a simple febricula. In other instances the fever persists for from ten days to two weeks; there are marked remissions, perhaps chills, with a furred tongue and low delir- ium. Jaundice is not infrequent. These are the cases to which the terms hilious remittent and typho-malarial fevers are applied. In other instances the symptoms become grave and assume the character of the pernicious type.
DISEASES DUE TO PROTOZOA. 21
It is in this form of malarial fever that so much confusion still exists. The similarity of the cases to typhoid fever is most striking, more particularly the appearance of the facies; the patient looks very ill. The cases occur, too, in the autumn, at the very time when typhoid fever occurs. The fever yields, as a rule, promptly to quinine, though here and there cases are met with — rarely indeed in my experience — which are refractory. It is just in this group that the observations of Laveran will be found of the greatest value. Several of the charts in Thayer and Hewetson's report show how closely, in some instances, the disease may simulate typhoid fever.
The diagnosis of malarial remittent fever may be definitely made by the examination of the blood. The small, actively motile, hyaline forms of the sestivo-autumnal parasite are to be found, while, if the case has lasted over a week, the larger crescentic and ovoid bodies are often seen. In many cases here we are at first unable to distinguish between typhoid and contin- ued malarial fever without a blood examination. A more widespread use of this means of diagnosis will enable us to bring some order out of the confu- sion which exists in the classification of the fevers of the Southern States. At present the following febrile affections are recognized by various physicians as occurring in the subtropical regions of America: (a) Typhoid fever; (h) typho-malarial fever — a typhoid modified by malarial infection, or the result of a combined infection; (c) the malarial remittent fever; and (d) continued thermic fever (Guiteras). In these various forms, all of which may be characterized by a continued pyrexia with remissions or with chills and sweats (for we must remember that chills and sweats in typhoid fever are by no means rare), the blood examination will enable us to discover those which depend upon the malarial poison. In many of these cases of continued or remittent fever careful inquiry will show that at the beginning the patient had several intermittent paroxysms. In Baltimore not many of the pro- tracted and severe cases have occurred, and I am inclined to think that future observations will show that, apart from the thermic fever, there are only two forms of these continued fevers in the South — the one due to the typhoid and the other to the malarial infection. The typhoid fever of Philadelphia and Baltimore presents no essential difference from the disease as it occurs in Montreal, a city practically free from malaria. Dock has shown conclusively that cases diagnosed in Texas as continued malarial fever were really true typhoid. The Widal reaction is now an important aid in diagnosis.
Pernicious Malarial Fever. — This is fortunately rare in temperate cli- mates, and the number of cases which now occur, for example, in Philadelphia and Baltimore, is very much less than it was thirty or forty years ago. Per- nicious fever is always associated with the sestivo-autumnal parasite. The following are the- most important types :
(a) The comatose form, in which a patient is struck down with symp- toms of the most intense cerebral disturbance, either acute delirium or, more frequently, a rapidly developing coma. A chill may or may not pre- cede the attack. The fever is usually high, and the skin hot and dry. The unconsciousness may persist for from twelve to twenty-four hours, or the patient may sink and die. After regaining consciousness a second attack may come on and prove fatal. In these instances, as has been stated, the special localization of the infection is in the brain, where actual thrombi
22 DISEASES DUE TO ANIMAL PARASITES.
of parasites with marked secondary changes in the surrounding tissues have been found.
(b) Algid Form. — In this, the attack sets in usually with gastric symp- toms; there are vomiting, intense prostration, and feebleness out of all proportion to the local disturbance. The patient complains of feeling cold, although there may be no actual chill. The temperature may be normal, or even subnormal; consciousness may be retained. The pulse is feeble and small, and the respirations are increased. There may be most severe diar- rhoea, the attack assuming a choleriform nature. The urine is often dimin- ished, or even suppressed. This condition may persist with slight exacerba- tions of fever for several days and the patient may die in a condition of profound asthenia. This is essentially the same as described as the asthenic or adynamic form of the disease. In the cases with vomiting and diarrhoea, Marchiafava has shown that the gastro-intestinal mucosa is often the seat of a special invasion by the parasites, actual thrombosis of the small vessels with superficial ulceration and necrosis occurring. Similar lesions were found by Barker in the gastro-intestinal tract of a case from my wards.
(c) Hcemorrliagic Forms — Black-water Fever — Hsemoglobinuric Fever — Malarial Hemoglobinuria. — In temperate regions these forms are rare; in the tropics they are common. In the Southern States there are many dis- tricts in which there is endemic hgemoglobinuria, believed to be of malarial origin, while in parts of Africa there is the much-disputed malady known as black-water fever. There seems to be no essential difference between the malarial hasmoglobinuria of the Southern States and the African black-water fever. As described by Stephens and Christophers (Eeport of Malaria Com- mittee, Fifth Series), for two or three days the patient has a rise of tem- perature, and if the blood is examined before the black-water the parasites are almost invariably present. If examined after the administration of quinine parasites are absent from the blood. These authors believe that there is a causal connection between the quinine and the black-water. It is impossible to say why quinine at one time can produce black-water, and at another, even a few hours or days later, it can not. Stephens' study (Thompson-Yates and Johnston Laboratory Eeports, 1903) gives the distribution of black-water fever in the Southern States, in Central America, in Italy, and in Africa. He gives a careful analysis of 95 cases. Malarial parasites were present in 95.6 per cent of the cases before the onset, and on the day of the appearance of the black-water in 61.9 per cent. There is no question as to the malarial nature of the disease, but whether there is a special malarial parasite is not yet settled. There is little evidence to show that the malarial hgemoglobinuria of the Southern States is due to quinine (Thayer). In most instances where the disease has been carefully studied, the paroxysms have occurred in indi- viduals who have been subject to frequently repeated attacks of malaria and have been reduced to a more or less cachectic condition. Only 8 cases occurred among the Isthmian Canal employees in 1907. Brem, Herrick, and the other workers on the Isthmus have not settled the relationship to the malarial attacks. They rather favour the view of some special character of the organ- ism. They do not think that quinine is an important factor; on the other hand, they find that intra-muscular injections of quinine are almost a specific, 10 grains every four hours for the first 48 hours.
DISEASES DUE TO PROTOZOA. 23
Malarial Cachexia. — The general symptoms are those of secondary anaemia — breathlessness on exertion, oedema of the ankles, haemorrhages, particularly into the retina. Occasionally the bleeding is severe, and I have twice known fatal haematemesis to occur in association with the enlarged spleen. The fever is variable. The temperature may be low for days, not going above 99.5°. In other instances there may be irregular fever, and the temperature rises gradually to 102.5° or 103°.
With careful treatment the outlook is good, and a majority of cases Re- cover. The spleen is gradually reduced in size, but it may take several months, or, indeed, in some instances several years, before the ague-cake entirely disappears.
Earer Complications. — Paraplegia may be due to a peripheral neuritis or to changes in the cord, and hemiplegia may occur in the pernicious comatose form, or occasionally at the very height of a paroxysm. Acute ataxia has been described, and there are remarkable cases with the symptoms of dissem- inated sclerosis (Spiller). Multiple gangrene may occur, as in an instance reported by me, in which a patient with sestivo-autumnal infection presented many areas on the skin. Orchitis has been described by Charvot in Algiers and Fedeli in Eome.
Prophylaxis. — In the discovery of Laveran there lay the promise of bene- fits more potent than any gift science had ever ofEered to mankind — viz., the possibility of the extermination of malaria. By the persistent missionary efforts of Boss this promise has reached the stage of practical fulfilment, and one of the greatest scourges of the race is now at our command. The story of the Canal Zone, Panama, under Colonel Gorgas is a triumph of the appli- cation of scientific methods. Between 1881 and 1904 among the employees of the French Canal Company (a maximum in 1887 of 17,885, of whom 15,726 were negroes) the monthly mortality ranged from 60 to 80, and on seven occasions was above 100, once reaching the enormous figure of 176.97 per 1,000. With the measures given below the mortality has fallen to that of temperate regions. For 1907 the death rate among white employees (10,709) was 16.71 per 1,000, among the negroes (28,634) 33.28 per 1,000. In May, 1908, the mortality among 44,816 employees had fallen to the remark- ably low figure of 10.44 per 1,000 !
The measures of prophylaxis are in the main three : ( 1 ) The rigid protec- tion of houses against mosquitoes by screens and the use of mosquito nets. The reports of the Italian Society for the Study of Malaria upon their efforts to protect the workers on the railways, as well as the work of Eoss at Ismailia, show how extraordinary are the results of these simple measures. The protec- tion of the sleeper at night is one of the most essential measures. (2) An earnest warfare against the mosquito on the part of sanitary authorities. In- struction should be furnished to the people upon the habits and life history of the insect, and of its relation to the disease. Pools, ponds, and marshy districts should be drained, and in the malaria season petroleum should be used freely, as it prevents the development of the larvae. Every case of malaria should be regarded as a centre of infection, and in a systematic warfare against the disease should be reported to the health authorities. In the tropics, segre- gation of Europeans may do much to lessen the chances of infection. (3) Lastly, every case should receive thorough and prolonged treatment with
24 DISEASES DUE TO ANIMAL PARASITES.
quinine. There is far too much carelessness on this point in the profes- sion. Malarial infection is a difficult one to eradicate. Quinine is the only known drug which is an effective parasiticide. Patients should be told to resume the treatment in the spring and autumn for several years after the primary infection. In very malarial districts, as many persons harbor the parasites, who do not show any (or at the most very few) signs, a systematic treatment with quinine should be instituted, particularly of the young children.
Diagnosis. — The endemic index of a country may be determined by the " parasite rate " or by the " spleen rate." It is best sought for in children in whom, as is well known, the infection may occur without much disturb- ance of the health. To determine the index by examining the blood for the parasites is a laborious and almost impossible task; on the other hand, as the work of Eoss in Greece and Mauritius has shown, the index may be readily gauged by an examination of the spleen. Thus, in the last-named island, of 31,022 children, 34.1 per cent had enlarged spleen.
The individual forms of malarial infection are readily recognized, but it requires a long and careful training to become an expert in blood examination. Great progress has been made in the past twenty years, and a diagnosis of malaria is no longer a refuge for our ignorance. One lesson it is hard for the practitioner to learn — namely, that an intermittent fever which resists quinine is not malarial.
The malarial poison is supposed to influence many affections in a remark- able way, giving to them a paroxysmal character. A whole series of minor ailments and some more severe ones, such as neuralgia, are attributed to certain occult effects of paludism. The more closely such cases are investi- gated the less definite appears the connection with malaria.
Treatment. — As a rule, anopheles are more likely to bite after sun- down, so that in regions in which the disease prevails extensively mosquito netting should be used. Persons going to a malarial region should take about 10 grains of quinine daily, though Sezary found that 2 grains three times a day was a sufficient protection against the disease. During the paroxysm the patient should, in the cold stage, be wrapped in blankets and given hot drinks. The reactionary fever is rarely dangerous even if it reaches a high grade. The body may, however, be sponged. In quinine we possess a specific remedy against malarial infection. Experiment has shown that the parasites are most easily destroyed by quinine at the stage when they are free in the circulation — ^that is, during and just after segmentation. While in most instances the parasites of the regularly intermittent fevers may be destroyed, even in the intra-corpuscular stage, in aestivo-autumnal fever this is much more difficult. It should, then, be our object, if we wish to most effectually eradicate the infection, to have as much quinine in circulation at the time of the paroxysm and shortly before as is possible, for this is the period at which segmentation occurs. In the regularly intermittent fevers from 10 to 30 grains in divided doses throughout the day will in many instances prevent any fresh paroxysms. If the patient comes under observation shortly before an expected paroxysm, the administration of a good dose of quinine just before its onset may be advisable to obtain a maximum effect upon that group of parasites. The quinine will not prevent the paroxysm, but will destroy the greater part of the group of organisms and prevent its further recurrence. It is safer to give
DISEASES DUE TO PARASITIC INFUSORIA. 25
at least 20 to 30 grains daily for the first three days, and then to continue the remedy in smaller doses for the next two or three weeks. In gestivo- autumnal fever larger doses may be necessary, though in relatively few in- stances is it necessary to give more than 30 to 40 grains in the twenty-four hours.
The quinine should be ordered in solution or in capsules. The pijls and compressed tablets are more uncertain, as they may not be dissolved.
A question of interest is the efficient dose of quinine necessary to cure the disease. I have a number of charts showing that grain doses three times a day will in many cases prevent the paroxysm, but not always with the cer- tainty of the larger doses. In cases of aestivo-autumnal fever with pernicious symptoms it is necessary to get the system under the influence of quinine as rapidly as possible. In these instances the drug should be administered hypo- dermically as the dihydrochlorate in 15 to 20 grain doses, every two or three hours. The muriate of quinine and urea is also a good form in which to administer the drug hypodermically ; 10, 15, or 20 grain doses may be neces- sary. In the most severe instances some observers advise the intravenous administration of quinine, for which the very soluble bimuriate is well adapted. Fifteen grains with a grain of sodium chloride may be injected in about 2 drachms of distilled water. For extreme restlessness in these cases opium is indicated, and cardiac stimulants, such as alcohol and strychnine, are necessary. If in the comatose form the internal temperature is raised, the patient should be put in a bath and doused with cold water. For malarial anaemia, iron and arsenic are indicated.
An interesting question is much discussed, whether quinine does not cause or at any rate aggravate the hasmoglobinuria. We have not yet seen a case in which this condition has occurred as a result of the use of the drug, and Bas- tianelli states that it is not seen in the Eoman malarial fevers. He recom- mends that in any case of hsemoglobinuria if the blood shows parasites quinine should be administered freely. In the post-malarial forms quinine aggravates the attack. In an active malarial infection the patient runs less risk with the quinine.
B. DISEASES DUE TO PARASITIC INFUSORIA.
Several flagellates are parasitic in man. The Trichomonas vaginalis, which measures 15 /a to 25 /x in length, and has four flagella, which are as long as or longer than the body, is by no means uncommon in the acid vaginal mucus.
The Trichomonas or C ercomonas hominis lives in the intestines, and is met with in the stools under all sorts of conditions. Freund from Dock's clinic has reported a series of cases which show that the parasite may cause acute and chronic diarrhoea with severe abdominal pain, and anatomically an acute enteritis. In one of Dock's cases the parasites were associated with a ha3mojrhagic cystitis without bacteria.
The Lamhlia intestinalis is another intestinal monad, larger than the common trichomonas. Flagellates have also been found in the expectoration
26 DISEASES DUE TO ANIMAL PARASITES.
in cases of gangrene of the lung and of bronchiectasis, and in the exudate of pleurisy.
The Balantidium coli, oval in form, 70 [x to 100 fi long and 50 /x to 70 /* broad, may be pathogenic. It is common in pigs, and has been known to produce an epidemic dysentery in apes (Harlow Brooks). The pathological significance of this parasite has been much discussed of late, particularly by Strong and Musgrave, Klimenko and Arkanazy. It has not only been found in the stools and on the mucous membrane of the intestine, but the parasites have occurred in the mucosa itself and in the submucosa. Apparently they do not extend beyond the wall of the bowel.
C. DISEASES DUE TO FLUKES.-DISTOMIASIS.
The following are important clinical forms :
1. Pulmonary Distomiasis ; Parasitic Haemoptysis. — Paragonimus (Dis- toma) Westermanii, the Asiatic lung or bronchial fluke, is from 8 to 16 mm. in length by 4 to 8 mm. broad, and of a pinkish or reddish-brown color.
It is found extensively in China and Japan and Formosa, and cases are occasionally imported into Europe and America. Stiles states that an im- ported case has been found in Portland, Oregon. It has been found in the United States in the cat, in the dog, and in the hog. One instance of pulmo- nary distomiasis has been reported caused by the giant liver fluke.
Clinically the disease, as described by Manson and Einger, is characterized by a chronic cough, with rusty-brown sputum, and occasional attacks of haemoptysis, usually trifling, but sometimes very severe. The ova, which are abundant in the sputum, are oval, smooth, and measure from 80 /x to 100 /* in length by 40 /a to 60 /a in breadth. The parasites may affect other organs — the liver and the brain.
2. Hepatic Distomiasis. — Five species of liver flukes of the family Fasciolidse are known to occur in man. More specifically these are : ( 1 ) The common liver fluke — Fasciola hepatica — which is a very common parasite in the ruminants; (2) The lancet fluke — dicrocoelium (Distoma) lanceatum; (3) Opisthorchis (Distoma) felineus, which is found in Prussia and Siberia, and by Ward in cats in Nebraska ; (4) Opisthorchis noverca — Distomum con- junctum — the Indian liver fluke described in man by McConnell; (5) Opis- thorchis {Distoma) sinensis, which is by far the most important of the liver flukes and occurs extensively in Japan, China, and India. It is 10 to 20 mm. long by 2 to 5 mm. broad. The eggs are oval, 27 fi to SO fi by 15 ju. to 17 fi, dark brown, with sharply defined operculum. A number of imported cases have been found in Canada and the United States. White found 18 cases in San Francisco.
The symptoms of hepatic distomiasis are best described in connection with this latter form. The following account is abstracted from Wallace Taylor. Young children are the chief sufferers. Many members of a family are usu- ally affected. In some villages a large proportion of the inhabitants are attacked. Among important symptoms are an irregular, intermittent diar- rhoea; at first there may or may not be blood. The liver gradually enlarges.
DISEASES DUE TO FLUKES— DISTOMIASIS. 27
There may be pain and an intermittent jaundice. There is not much fever. After lasting for two or three years dropsy comes on, anasarca and ascites. The patient is greatly reduced by the diarrhoea and becomes very anaemic. Even then transient recovery may take place, but as a rule there is a recur- rence, and the patient dies after many years of illness. The ova of the para- site are readily found in the stools.
3. Intestinal Distomiasis. — In India the Fasciolopsis (Distoma) BusMi has been found in a number of cases in the small intestines. The Mesogoni- mus heterophyes has been found in Egypt and Japan.
The Asiatic Amphistome — Gastrodiscus (Ampliistoma) liominis — a not uncommon parasite in India — is easily recognized by its large posterior sucker.
4. Haemic Distomiasis; Bilharziosis. — One of the most important of para- sitic diseases, caused by the blood fluke, Scliistosom.um hcematobium or Bil- harzia licematohia. Endemic hgematuria has been known for many years, particularly in Egypt, where in 1851 Bilharz discovered the parasite of the disease. It prevails in South and North Africa, particularly the latter, in Arabia, Persia, and the west coast of India. Imported cases are not very uncommon in Europe, and an occasional instance is met with in the United States. In Lower Egypt it is met with in one third of all the autopsies. An Asiatic blood fluke, Schistosomum japonicum, has recently been discov- ered which differs in small details from the African variety.
The parasite is singular among flukes as having the sexes separate, and the male usually carries the female in a gynsecophorous canal. The mode of entrance into the body is unknown, whether by the mouth, the urethra, or through the skin. The eggs are very characteristic, oval in shape, 0.16 mm. by 0.06 mm., and one end has a terminal spine. The eggs hatch in water, but the further development of the free-swimming embryos has not been followed. Taken into the body, possibly with water or on cresses, it reaches the portal veins, in which the worms are most commonly found, usually young speci- mens and uncoupled. The males bearing the females creep to various parts, particularly the bladder and rectum. The eggs are laid in the tissues, but wander, like other sharp foreign bodies, and escape with the urine and faeces. A majority of them remain in the tissues and cause irritation, fibroid changes, and papillomata in the bladder and rectum. Collecting in the bladder as foreign bodies they form the nuclei of calculi.
Symptoms. — As is so often the ease with animal parasites, they may cause no inconvenience. Irritability of the bladder, dull pain in the peri- nseum, and haematuria are the most frequent symptoms. A chronic cystitis follows when the walls of the bladder are much thickened by the irritation caused by the ova. The angemia caused by the haemorrhage is slight in com- parison with that of ankylostomiasis. When the rectum is involved there are straining and tenesmus, with the passage of mucus and blood ; in severe cases large papillomata and a chronic ulcerative proctitis. There may be a chronic vaginitis.
Of the complications, calculi in kidney and bladder are the most impor- tant. Milton, Madden, and others of the Cairo School of Medicine have stud- ied carefully the surgical aspects of the disease. Periurethral abscess and perineal fistulse are very common in the chronic cases.
Few symptoms are caused by the presence of the parasites in the portal
28 DISEASES DUE TO ANIMAL PARASITES.
veins, but there may be an advanced cirrhosis of a Glissonian type due to ail enormous thickening of the periportal tissues (Symmers). This author has also reported an instance of the Bilharzia in the pulmonary blood in a case of Bilharzial colitis, and the worms were found living in the pulmonary circulation.
The diagnosis is readily made by finding the characteristic ova in the bloody urine or in the blood and mucus from the rectum. The Bilharzia may be present in the body for years without producing serious damage, and in slight infections the symptoms may disappear (Sand with), particularly in children.
Schistosoma Japonicum vel Cattoi. — In China and Japan and in the Phil- ippines there is a disease characterized by cirrhosis of the liver, splenomegaly, ascites, dysentery, progressive anaemia, and sometimes by localized epilepsy. It occurs extensively in one district of Japan, and is known as the " Kata- yama " disease. Woolley has met with it in the Philippines, and Catto in China. The parasite lives in the vessels of the alimentary canal; the ova are smaller than those of S. licematobium, and have not the characteristic spinous ends.
Treatment. — ^We know of nothing which can kill the parasites in the blood. Extract of male fern is recommended for the hsematuria. The chronic cystitis and proctitis demand the usual measures for these disorders.
D. DISEASES CAUSED BY CESTODES.
{Tceniasis; Hydatid Disease.)
Man harbors the adult parasites in the small intestine, the larval forms in the muscles and solid organs.
I. INTESTINAL CESTODES; TAPE- WORMS.
Taenia solium, or pork tape-worm. This is not a common form in North America. It is much more frequent in parts of Europe and Asia. When mature it is from 6 to 12 feet in length. The head is small, round, not so large as the head of a pin, and provided with four sucking disks and a double row of hooklets; hence it is called, in contradistinction to the other form in man, the armed tape-worm. To the head succeeds a narrow, thread-like neck, then the segments, or proglottides, as they are called. The segments possess both male and female generative organs, and at about the four-hundred-and-fiftieth they become mature and contain ripe ova. The worm attains its full growth in from three to three and a half months, after which time the segments are continuously shed and appear in the stools. The segments are about 1 cm. in length and from 7 to 8 mm. in breadth. Pressed between glass plates the uterus is seen as a median stem with about eight to fourteen lateral branches. There are many thousands of ova in each ripe segment, and each ovum consists of a firm shell, inside of which is a little embryo, provided with six hooklets. The segments are continuously passed, and if the ova are to attain further development they must be taken into the stomach, either of a pig, or of man himself. The egg-shells are digested, the
DISEASES CAUSED BY CESTODES. 29
six-hooked embryos become free, and passing from the stomach reach various parts of the body (the liver, muscles, brain, or eye), where they develop into the larvae or cysticerci. A hog under these circumstances is said to be measled, and the cysticerci are spoken of as measles or bladder worms.
Tmnia solium received its name because it was thought to exist as a soli- tary parasite in the bowel, but two or three or even more worms may occijr.
Taenia saginata or mediocanellata — unarmed, fat, or beef tape-worm. This is a longer and larger parasite than Tcenia solium. It is certainly the common tape-worm of j^orth America. Of scores of specimens which I have examined almost all were of this variety. According to Berenger-Feraud it has spread rapidly in western Europe, owing probably to the importation of beef and live-stock from the Mediterranean basin. It may attain a length of 15 or 20 feet, or more. The head is large in comparison with that of TcBnia solium, and measures over 2 mm. in breadth. It is square-shaped and provided with four large sucking disks, but there are no hooklets. The ripe segments are from 17 to 18 mm. in length and from 8 to 10 mm. in breadth. The uterus consists of a median stem with from fifteen to thirty- five lateral branches, which are given ofE more dichotomously than in Tcenia solium. The ova are somewhat larger, and the shell is thicker, but the two forms can scarcely be distinguished by their ova. The ripe segments are passed as in Tcenia solium, and are ingested by cattle, in the flesh or organs of which the eggs develop into the bladder worms or cysticerci.
Of other forms of tape-worm may be mentioned:
Dipylidium caninum (Taenia elliptica, Taenia cucumerina) . — A small parasite very common in the dog and occasionally found in man; the larvaj develop in the lice and fleas of the dog.
Hymenolepsis diminuta (Taenia flavo-punctata) . — This small cestode was found in the intestine of a child in Boston, and has since been met with in twelve cases (Eausom). It is common in rats. The larvae develop in Lepi- doptera and in beetles.
Hymenolepsis nana (Taenia nana) occurs not infrequently in Italy. It is not very uncommon in the United States (Stiles). The Davainea mada- gascariensis (Tcenia madagascariensis) is a rare form.
Taenia confusa, a new species described by Ward.
Bothriocephalus latus. — A cestode worm found only in certain districts bordering on the Baltic Sea, in parts of Switzerland, and in Japan. ISTicker- son has shown that it is common among the Finns in the Northwestern States. The parasite is large and long, measuring from 25 to 30 feet or more. Its head is different from that of the taenia, as it possesses two lateral grooves or pits and has no hooklets. The larvae develop in the peritonaeum and mus- cles of the pike and other fish, and it has been shown experimentally that they grow into the adult worm when eaten by man.
Symptoms. — These parasites are found at all ages. They are not uncom- mon in children and are occasionally found in sucklings. W. T. Plant refers to a number of cases in children under two years, and there is one in the liter- ature in which it is stated that the tape-worm was found in an infant five days old !
The parasites may cause no disturbance and are rarely dangerous. A knowledge of the existence of the worm is generally a source of worry and
30 DISEASES DUE TO ANIMAL PARASITES.
anxiety; the patient may have considerable distress and complain of ab- dominal pains, nausea, diarrhoea, and sometimes anemia. Occasionally the appetite is ravenous. In women and in nervous patients the constitutional disturbance may be considerable, and we not infrequently see great mental depression and even hypochondria. Various nervous phenomena, such as chorea, convulsions, or epilepsy, are believed to be caused by the parasites. Such effects, however, are very rare. The Bothriocephalus may cause a severe and even fatal form of anaemia, which has been described fully in the monograph of Schaumann, of Helsingfors. It has been suggested that the metabolic products of the worm may have in some cases a hsemolytic action.
The diagnosis is never doubtful. The presence of the segments is dis- tinctive. The ova, too, may be recognized in the stools. It makes but little difference as to the form of tape-worm, but the ripe segments of Tcenia sagi- nata are larger and broader, and show differences in the generative system as already* mentioned.
The prophylaxis is most important. Careful attention should be given to three points. First, all tape- worm segments should be burned; they should never be thrown into the water-closet or outside ; secondly, careful inspection of meat at the abattoirs; and thirdly, cooking the meat sufficiently to kill the parasites.
In the case of the beef measles, the distribution of the parasites, as given by Ostertag, shows that the muscles of the jaw are much more fre- quently affected than other parts — 360 times, while other organs were infected but 55 times. Sometimes there are instances of general infection. Stiles states that no exact statistics have been published for this country. In Ber- lin the proportion of cattle infected in 1892-'93 was about 1 to 672. Cold storage kills the cysticercus usually within three weeks. The measles are more readily overlooked in beef than in pork, as they do not present such an opaque white color.
In the examination of hogs for cysticerci " particular stress should be laid upon the tongue, the muscles of mastication, and the muscles of the shoulder, neck, and diaphragm" (Stiles). They may be seen very easily on the under surface of the tongue. American hogs are comparatively free. In Prussia one hog is infected in about every 637. Specimens have been found alive twenty-nine daj^s after slaughtering. In the examination of 1,000 hogs in Montreal, Clement and I found 76 instances of cysticerci. For full details with reference to the inspection of meat for animal parasites, the practitioner is referred to the work of Dr. Stiles, in Bulletin No. 19, United States Department of Agriculture, 1898.
Treatment. — For two days prior to the administration of the reme- dies the patient should take a very light diet and have the bowels moved occasionally by a saline cathartic. The practitioner has the choice of a large number of drugs. As a rule, the male fern acts promptly and well. The ethereal extract, in 2-drachm doses, may be given fasting, and followed in the course of a couple of hours by a brisk purgative. This usually succeeds in bringing away a large portion, but not always the entire worm.
A combination of the remedies is sometimes very effective. An infusion is made of pomegranate root, half an ounce; pumpkin seeds, 1 ounce; pow-
DISEASES CAUSED BY CESTODES. 31
dered. ergot, a drachm ; and boiling water, 10 ounces. To an emulsion of the male fern (a drachm of ethereal extract), made with acacia powder, 2 minims of croton oil are added. The patient should have had a low diet the previous day and have taken a dose of salts in the evening. The emulsion and infusion are mixed and taken fasting at nine in the morning.
The pomegranate root is a very efficient remedy, and may be given as an infusion of the bark, 3 ounces of which may be macerated in 10 ounces of water and then reduced to one half by evaporation. The entire quan- tity is then taken in divided doses. It occasionally produces colic, but is a very effective remedy. The active principle of the root, pelletierine, is now much employed. It is given in doses of 6 to 8 or even 10 grains, with a little tannin (grs. v) in sweetened water, and is followed in an hour by a purge.
Pumpkin seeds are sometimes very efficient. Three or 4 ounces should be carefully bruised and then macerated for twelve or fourteen hours, and the entire quantity taken and followed in an hour by a purge. Of other remedies, koosso, turpentine in ounce doses in honey, and kamala may be mentioned.
Unless the head is brought away, the parasite continues to grow, and within a few months the segments again appear. Some instances are extraordinarily obstinate. Doubtless almost everything depends upon the exposure of the worm. The head and neck may be thoroughly protected beneath the valvulse conniventes, in which case the remedies may not act. Owing to its armature Tcenia solium is more difficult to expel. It is probable that no degree of peristalsis could dislodge the head, and unless the worm is killed it does not let go its extraordinarily firm hold on the mucous mem- brane. If hot water be put in the commode the worm is less likely to con- tract and be broken, a practice recommended by Celsus.
II. SOMATIC T-ffiNIASIS.
Whereas adult taenia may give rise to little or no disturbance, and rarely, if ever, prove directly fatal, the affections caused by the larvae or immature forms in the solid organs are serious and important. There are two chief cestode larvas known to frequent man : (a) the Cysticercus cellulosce, the larva of Tcenia solium, and (&) the Ecliinococcus, the larva of Tcenia echinococcus. The Cysticercus tcenice saginatce has been found only two or three times in man.
Cysticercus Cellulosae. — When man accidentally takes into his stomach the ripe ova of Tania solium he is liable to become the intermediate host, a part usually played for this tape-worm by the pig. This accident may occur in an individual the subject of Tcenia solium, in which case the mature proglottides either themselves wander into the stomach or, what is more likely, are forced into the organ in attacks of prolonged vomiting. Of course the accidental ingestion from the outside of a few ova is quite possible, and the liability of infection should always be borne in mind in handling the seg- ments of the worm.
The symptoms depend entirely upon the number of ova ingested and
S2 DISEASES DUE TO ANIMAL PARASITES.
the localities reached. In the hog the cysticerci produce very little dis- turbance. The muscles, the connective tissue, and the brain may be swarm- ing with the measles, as they are called, and yet the nutrition is maintained and the animal does not appear to be seriously incommoded. In the in- vasion period, if large numbers of the parasites are taken, there is, in all probability, constitutional disturbance ; certainly this is seen in the calf, when fed with the ripe segments of Tcenia saginata.
In man a few cysticerci lodged beneath the skin or in the muscles give no trouble, and in time the larvae die and become calcified. They are occa- sionally found in dissection subjects or in post mortems as ovoid white bodies in the muscles or subcutaneous tissue. In America they are very rare. I saw but one instance in my post-mortem experience. Depending on the num- ber and the locality specially affected, the symptoms may be grouped into gen- eral, cerebro-spinal, and ocular. In 155 cases compiled by Stiles, the para- site in 117 was found in the brain, in 3.2 in the muscles, in 9 in the heart, in 3 in the lungs, subcutaneously in 5, in the liver in 2.
1. General. — As a rule the invasion of the larvae in man, unless in very large numbers, does not cause very definite symptoms. It occasionally hap- pens, however, that a striking picture is produced. A patient was admitted to my wards very stiff and helpless, so much so that he had to be assisted upstairs and into bed. He complained of numbness and tingling in the extremities and general weakness, so that at first he was thought to have a peripheral neuritis. At the examination, however, a number of painful subcu- taneous nodules were discovered, which proved on excision to be the cysticerci. Altogether 75 could be felt subcutaneously, and from the soreness and stiff- ness they probably existed in large numbers in the muscles. There were none in his eyes, and he had no brain symptoms.
2. Cerebro-spinal. — Remarkable symptoms may result from the presence of the cysticerci in the brain and cord. In the silent region they may be abundant without producing any symptoms. I have in my possession the brain of a pig containing scores of " measles," yet the animal in the few moments in which I saw it just prior to death did not present any symptoms to attract attention. In the ventricles of the brain the cysticerci may attain a considerable size, owing to the fact that in regions in which they are unre- strained in their growth, as in the peritonseum, the bladder-like body grows freely. When in the fourth ventricle, remarkable irritative symptoms may be produced. In 1884 I saw with Friedlander in Berlin a case from Riess's wards in which during life there had been symptoms of diabetes and anom- alous nervous symptoms. Post mortem, the cysticercus was found beneath the valve of Vieussens, pressing upon the floor of the fourth ventricle.
3. Ocular. — Since von Graefe demonstrated the presence of the cysticer- cus in the vitreous humor many cases have been placed on record, as it is a condition easily recognized.
Except in the eye, the diagnosis can rarely be made; when the cysticerci are subcutaneous, one may be excised. It is possible that when numerous throughout the muscles they may be seen under the tongue, in which situa- tion they may exist in the pig in numbers.
Echinococcus Disease. — The hydatid worms or echinococci are the larvae of Tcenia echinococcus of the dog. This is a tiny cestode not more than 4
DISEASES CAUSED BY CESTODES. 33
or 5 mm. in length, consisting of only three or four segments^ of which the terminal one alone is mature, and has a length of about 3 mm. and a breadth of 0.6 mm. The head is small and provided with four sucking disks and a rostellum with a double row of booklets. This is an exceedingly- rare parasite in the dog. Cobbold states that he has never met with a natural specimen in England. Leidy had not one in his large collection. I have not met with an instance in America; Curtice, of Washington, found it once in an American dog. The worms are so small that they may be readily over- looked, since they form small white, thread-like bodies closely adherent among the villi of the small intestines. The ripe segment contains about 5,000 eggs, which attain their development in the solid organs of various animals, particu- larly the hog and ox, more rarely the horse and the sheep. In some countries man is a common intermediate host, owing to the accidental ingestion of the ova.
Development. — The little six-hooked embryo, freed from the egg-shell by digestion, burrows through the intestinal wall and reaches the peritoneal cav- ity or the muscles ; it may enter the portal vessels and be carried to the liver. It maj'' enter the systemic vessels, and, passing the pulmonary capillaries, as it is protoplasmic and elastic, may reach the brain or other parts. Once having reached its destination, it undergoes the following changes : The hooklets disappear and the little embryo is gradually converted into a small cyst which presents two distinct layers — an external, laminated, cuticular membrane or capsule, and an internal, granular, parenchymatous layer, the endocyst. The little cyst or vesicle contains a clear fluid. There is more or less reaction in the neighboring tissues, and the cyst in time has a fibrous investment. When this primary cyst or vesicle has attained a certain size, buds develop from the parenchymatous layer, which are gradually converted into cysts, present- ing a structure identical with that of the original cyst, namely, an elastic chitinous membrane lined with a granular parenchymatous layer. These sec- ondary or daughter cysts are at first connected with the lining membrane of the primary cyst, but are soon set free. In this way the parent cyst as it grows may contain a dozen or more daughter cysts. Inside these daughter cysts a similar process may occur, and from buds in the walls granddaughter cysts are developed. From the granular layer of the parent and daughter cysts buds arise which develop into brood capsules. From the lining mem- brane the little outgrowths arise and gradually develop into bodies known as scolices, which represent in reality the head of the Tcenia echinococcus and present four sucking disks and a circle of hooklets. Each scolex is capable when transferred to the intestines of a dog of developing into an adult tape- worm. The difference between the ovum of an ordinary tape-worm, such as Tcenia solium^ and Tcenia echinococcus is in this way very striking. In the former case the ovum develops into a single larva — Cysticercus cellulosce — whereas the egg of Tcenia echinococcus develops into a cyst which is capa- ble of multiplying enormously and from the lining membrane of which millions of larval tape-worms develop. Ordinarily in man the development of the echinococcus takes place as above mentioned and by an endogenous form in which the secondary and tertiary cysts are contained within the primary; but in animals the formation may be different, as the buds from the primary cyst penetrate between the layers and develop externally, forming the exoge- 4
34 DISEASES DUE TO ANIMAL PARASITES.
nous variety. A third form is the multilocular echinococciis, in which form the primary cj^st huds develop which are cut off completely and are sur- rounded by thick capsules of a connective tissue, which join together and ultimately form a hard mass represented hy strands of connective tissue enclosing alveolar spaces about the size of peas or a little larger. In these spaces are found the remnants of the eehinococcus cyst, occasionally the scolices or booklets, but they are often sterile.
The fluid is limpid, non-albuminous; specific gravity 1.005 to 1.009, occa- sionally higher. It ma}' contain sugar and succinic acid, and after repeated tapping of the cyst, albumin. When not degenerated, the hydatid heads or the characteristic booklets are found in the contents of the cyst.
Chaxgbs IX THE Cyst. — It is not known definitely how long the eehino- coccus remains alive, probably many years, possibly as long as twent}' years. The most common change is death and the gradual inspissation of the contents and conversion of the cyst into a mass containing putty-like or granular mate- rial which may be partially calcified. Eemnants of the chitinous cyst wall or booklets may be found. These obsolete hydatid cysts are not infrequently found in the liver. A more serious termination is rupture, which may take place into a serous sac, or perforation may take place externally, when the cysts are discharged, as into the bronchi or alimentary canal or urinary passages. More unfavorable are the instances in which rupture occurs into the bile-passages or into the inferior cava. Eecovery ma}' follow the rupture and discharge of the hydatids externally. Sudden death has been known to follow the rupture. A third and very serious mode of termination is suppura- tion, which may occur spontaneously or follow rupture and is found most frequently in the liver.
Geographical Distribution op the Echinococcus. — The disease pre- vails most extensively in those countries in which man is brought into close contact with the dog, particularly when, as in Australia, the dogs are used for herding sheep, the animal in which the larval form of Tcenia eehinococcus is most often found. In Iceland the cases are very numerous. In Europe the disease is not uncommon. In Great Britain and in North America it is rare, and a majority of the cases are in foreigners. Statistics of the preva- lence of the disease in America have been published by Osier (1882), Som- mer (1895-'96), and by Lyon (1902), who has collected 211 cases. Of these, 136 cases were in foreigners; in 92 the nationality was not stated; 10 were negroes; 2 Canadians, and only 1 a native American. Fifty-six cases oc- curred in Manitoba, in which province there is a large settlement of Icelanders, who have brought the disease with them. Only one instance is known in a Canadian-born ofl^spring of an Icelandic emigrant.
Distribution in the Body. — Of 1,634 cases comprised in the statistics of -Davaine, Boeker, Finsen, and Neisser, the parasite existed in the liver in 820; in the lung or pleura in 137; in the abdominal organs, including the kidneys, bladder, and genitalia, in 331 ; in the nervous system in 122 ; in the circulatory system in 42; in other organs 179. Of the 241 eases in Lyon's series in this country the liver was the seat in 177, and the omentum, peri- toneal cavity, and mesentery in 26. In 11 cases cysts were passed per rectum, in 7 cases cysts or booklets were expectorated, and in 2 cases passed per urethram.
DISEASES CAUSED BY CESTODES. 35
Symptoms. — 1. Hydatids of the Liver. — Small cysts may cause no dis- turbance; large and growing cysts produce signs of tumor of the liver with great increase in the size of the organ. Naturally the physical signs depend much upon the situation of the growth. Near the anterior surface in the epigastric region the tumor may form a distinct prominence and have a tense, firm feeling, sometimes with fluctuation. A not infrequent situation is to the left of the suspensory ligament, the resulting tumor pushing up the heart and causing an extensive area of dulness in the lower sternal and left hypo- chondriac regions. In the right lobe, if the tumor is on the posterior sur- face, the enlargement of the organ is chiefly upward into the pleura and the vertical area of dulness in the posterior axillary line is increased. Super- ficial cysts may give what is known as the hydatid fremitus. If the tumor is palpated lightly with the fingers of the left hand and percussed at the same time with those of the right, there is felt a vibration or trembling movement which persists for a certain time. It is not always present, and it is doubtful whether it is peculiar to the hydatid tumors or is due, as Briangon held, to the collision of the daughter cysts. Very large cysts are accompanied by feelings of pressure or dragging in the hepatic region, sometimes actual pain. The general condition of the patient is at first good and the nutrition little, if at all, interfered with. Unless some of the accidents already referred to occur, the symptoms indeed may be trifling and due only to the pressure or weight of the tumor.
Historically, one of the most interesting cases is that of the first Lord Shaftesbury (Achitopel), who had a tumor below the costal border for many years. It suppurated and was opened by the philosopher John Locke, his physician, who describes with great detail the escape of the bladder-like bodies. Among the Shaftesbury papers in the Eecord Office are several other cases col- lected by Locke ; the disease may have been more common in England at that period.
Suppuration of the cyst changes the clinical picture into one of pyaemia. There are rigors, sweats, more or less jaundice, and rapid loss of weight. Perforation may occur into the stomach, colon, pleura, bronchi, or exter- nally, and in some instances recovery has taken place. Perforation has occurred into the pericardium and inferior vena cava; in the latter case the daughter cysts have been found in the heart, plugging the tricuspid orifice and the pulmonary artery. Perforation of the bile-passages causes intense jaundice, and may lead to suppurative cholangitis.
An interesting symptom connected with the rupture of hydatid cysts is the occurrence of urticaria, which may also follow aspiration of the cysts. Brieger has separated a highly toxic material from the fluid, and to it the symptoms of poisoning may be due.
Diagnosis. — Cysts of moderate size may exist without producing symp- toms. Large multiple echinococci may cause great enlargement with irregu- larity of the outline, and such a condition persisting for any time with reten- tion of the health and strength suggests hydatid disease. An irregular, pain- less enlargement, particularly in the left lobe, or the presence of a large, smooth, fluctuating tumor of the epigastric region is also very suggestive, and in this situation, when accessible to palpation, it gives a sensation of a smooth elastic growth and possibly also the hydatid tremor. When suppu-
36 DISEASES DUE TO ANIMAL PARASITES.
ration occurs the clinical picture is really that of abscess, and only the exist- ence of previous enlargement of the liver with good health would point to the fact that the suppuration was associated with hydatids. Syphilis may pro- duce irregular enlargement without much disturbance in the health, some- times also a very definite tumor in the epigastric region, but this is usually firm and not fluctuating. The clinical features may simulate cancer very closely. In a case which I reported the liver was greatly enlarged and there were many nodular tumors in the abdomen. The post mortem showed enor- mous suppurating hydatid cysts in the left lobe of the liver which had perforated the stomach in two places and also the duodenum. The omen- tum, mesentery, and pelvis also contained numerous cysts. As a rule, the clinical course of the disease would suffice to separate it clearly from cancer. Dilatation of the gall-bladder and hydronephrosis have both been mistaken for hydatid disease. In the former the mobility of the tumor, its shape, and the mucoid character of the contents suffice for the diagnosis. In some in- stances of hydronephrosis only the exploratory puncture could distinguish between the conditions. More frequent is the mistake of confounding a hydatid cyst of the right lobe pushing up the pleura with pleural effusion of the right side. The heart may be dislocated, the liver depressed, and dulness, feeble breathing, and diminished fremitus are present in both conditions. Frerichs lays stress upon the different character of the line of dulness ; in the echinococcus cyst the upper limit presents a curved line, the maximum of which is usually in the scapular region. Suppurative pleurisy may be caused by the perforation of the cyst. If adhesions result, the perforation takes place into the lung, and fragments of the cysts or small daughter ejsts may be coughed up. For diagnostic purposes the exploratory puncture should be used. As stated, the fluid is usually perfectly clear or slightly opalescent, the reaction is neutral, and the specific gravity varies from 1.005 to 1.009. It is non-albuminous, but contains chlorides and sometimes traces of sugar. Hooklets may be found either in the clear fluid or in the suppurating cysts. They are sometimes absent, however, as the cyst may be sterile.
2. EcHixococcus OF THE Eespikatory System. — Of 809 cases of single hydatid cyst collected by Thomas in Australia, the lung was affected in 134 cases. Of 241 American cases, in 16 the pleura or lung was affected. The larvas may develop primarily in the pleura and attain a large size. The s}Tnptoms are at first those of compression of the lung and dislocation of the heart. The physical signs are those of fluid in the pleura. The line of dul- ness may be quite irregular. As in the echinococcus of the liver, the general condition of the patient may be excellent in spite of the existence of extensive disease. Pleurisy is rarely excited. The cysts may become inflamed and perforate the chest wall. Cary and Lyon have analyzed 40 cases of primary echinococcus cjst of the pleura; death results in a majority of the cases from the toxgemia following the rupture and the absorption of the fluid or from the sepsis following suppuration.
Echinococci occur more frequentty in the lung than in the pleura. If small, they may exist for some time without causing serious s}TiLptoms. In their growth they compress the lung and sooner or later lead to inflamma- tory processes, often to gangrene, and the formation of cavities which connect with the bronchi. Fragments of membrane or small cysts may be expectorated.
DISEASES CAUSED BY CESTODES. 37
HEemorrhage is not infrequent. Perforation into the pleura with empyema is common. A majority of tlie cases are regarded during life as either phthi- sis or gangrene, and it is only the detection of the characteristic membranes or the booklets which leads to the diagnosis. Of a series of 21 cases, 17 recov- ered; 5 of the cases suppurated (C. H. Fleming, Victoria, personal communi- cation) .
3. EcHiNOCOccus OF THE KiDNEYS. — In the collected statistics referred to above, the genito-urinary system comes second as the seat of hydatid disease, though here the affection is rare in comparison with that of the liver. ' Of the 341 American cases, there were 17 in which the kidneys or bladder were involved. The kidney may be converted into an enormous cyst resembling a hydronephrosis.
The diagnosis is only possible by puncture and examination of the fluid. The cyst may perforate into the pelvis of the kidney, and portions of the membrane or cj'^sts may be discharged with the urine, sometimes producing renal colic. I have reported a case in which for many months the patient passed at intervals numbers of small cysts with the urine. The general health was little if at all disturbed, except by the attacks of colic during the passage of the parasites.
4. EcHiNOCOCCUS OF THE Kervous System. — The common cystic disease of the choroidal plexuses has been mistaken for hydatids. Davies Thomas, of Australia, has tabulated 97 cases, including some of the Cysticercus cellu- loses. According to his statistics, the cyst is more common on the right than on the left side, and is most frequent in the cerebrum.
The symptoms, very indefinite, as a rule, are those of tumor. Persistent headache, convulsions, either limited or general, and gradually developing blindness have been prominent features in many cases.
Multilocular Echinococcus. — This form merits a brief separate descrip- tion, as it differs so remarkably from the usual type. It has been met with only in Bavaria, Wlirtemberg, the adjacent districts of Switzerland, and in the Tyrol. Possett has reported 13 cases from von Eokitansky's clinic at Innsbruck. In the United States six cases have been described, chiefly in Ger- mans. Delafield and Prudden's patient had lived there five years, and for a year before his death had been jaundiced. A fluctuating tumor was found in the right flank, apparently connected with the liver. This was opened, and death followed from haemorrhage. In Oertel's case the patient had lived there ten years. He was deeply jaundiced, and had a tumor mass at the right bor- der of the liver, which was enlarged. Bacon resected a cyst from the left lobe of the liver. The primary tumor presents irregularly formed cavities sepa- rated from each other by strands of connective tissue, and lined with the echinococcus membrane. The cavities are filled with a gelatinous material, so that the tumor has very much the appearance of an alveolar colloid cancer. It is quite possible that a special form of taenia echinococcus represents the adult type of this peculiar parasite. This form is almost exclusively confined to the liver, and the symptoms resemble more those of tumor or cirrhosis. The liver is, as a rule, enlarged and smooth, not irregular as in presence of the ordinary echinococcus. Jaundice is a common symptom. The spleen is usually enlarged, there is progressive emaciation, and toward the close hsem- orrhages are common.
38 DISEASES DUE TO ANIMAL PARASITES.
Treatment of Echinococcus Disease. — Medicines are of no avail. Post- mortem reports show that in a considerable number of cases the parasite dies and the cyst becomes harmless. Operative measures should be resorted to when the cyst is large or troublesome. The simple aspiration of the con- tents has been successful in a large number of cases, and as it is not in any way dangerous, it may be tried before the more radical procedure of incision and evacuation of the cysts. Suppuration has occasionally followed the punc- ture. Injections into the sac should not be practised. With modern methods surgeons now open and evacuate the echinococcus cysts with great boldness, and the Australian records, which are the most numerous and important on this subject, show that recovery is the rule in a large proportion of the cases. Suppurative cysts in the liver should be treated as abscess. ISTaturally the outlook is less favorable. The practical treatment of h3'datid disease has been greatly advanced by Australian surgeons. The works of the Australian physicians James Graham and Thomas may be consulted for interesting details in diagnosis and treatment.
E. DISEASES CAUSED BY NEMATODES.
I. ASCARIASIS.
Ascaris Lumbricoides, the most common human parasite, is found chiefly in children. The female is from 7 to 12 inches in length, the male from 4 to 8 inches. In form it is cylindrical, pointed at both ends, with a yel- lowish-brown, sometimes a slightly reddish color. Four longitudinal bands can be seen, and it is striated transverseh''. The ova, which are sometimes found in large numbers in the faeces, are small, brownish-red in color, elliptical, and have a very thick covering. They measure 0.075 mm. in length and 0.058 mm. in width. The life history has been demonstrated to be " direct " — i. e., without intermediate host. The parasite occupies the upper portion of the small intestine. Usually not more than one or two are present, but occasion- ally they occur in enormous numbers. The migrations are peculiar. They may pass into the stomach, whence thej^ may be ejected by vomiting, or they may crawl up the oesophagus and enter the phar^mx, from which they may be withdrawn. A child under my care in the small-pox department of the Montreal General Hospital, during convalescence, withdrew in this way more than thirty round worms within a few weeks. In other instances the worm reaches the larynx, and has been known to produce fatal asphyxia, or, passing into the trachea, to cause gangrene of the lung. They may go through the Eustachian tube and appear at the external meatus. The worms have been found in extraordinary numbers in the bile-ducts. Eemarkable specimens exist in the Dupuytren, the Wistar-Horner (Philadelphia), and the N'etley Museums. Chalmers (Ceylon) and Leys (U. S. jST.) have called attention to their importance in causing abscess of the liver. Ebstein reports certain markings, strangulations, on the round worm, as if they had been nipped in the bile-ducts ! The bowel may be blocked, or in rare instances an ulcer may be perforated. Even the healthy bowel wall may be penetrated (Apostolides).
A peculiarly irritating substance, often evident to the sense of smell in
DISEASES CAUSED BY NEMATODES. 39
handling specimens, is formed by the round worms. Peiper and others sug- gest that the nervous symptoms, sometimes resembling those of meningitis, are due to this poison. Chauffard, Marie, and Tauchon have gone still fur- ther, and report a remarkable condition of fever, intestinal symptoms, foul breath, and intermittent diarrhoea in connection with the presence of lum- bricoides. They call it typho-lumbricosis. The febrile condition may con- tinue for a month or more. There may be eosinophilia to 25 per cent to 30 per cent, and in some cases a marked anaemia. The question of the toxins produced by intestinal parasites is still an open one.
A few parasites may cause no disturbance. In children there are irrita- tive symptoms usually attributed to worms, such as restlessness, irritability, picking at the nose, grinding of the teeth, twitchings, or convulsions.
Treatment. — Santonin can be given, mixed with sugar, in doses of from one half to one grain for a child and two to three grains for an adult, fol- lowed by a calomel or a saline purge. The dose may be given for three or four days. An unpleasant consequence which sometimes follows the admin- istration of this drug is xanthopsia or yellow vision.
Oxyuris Vermicularis (Thread-worm; Pin-worm). — This common para- site occupies the rectum and colon. The male measures about 4 mm. in length, the female about 10 mm. They produce great irritation and itching, particularly at night, symptoms which become intensely aggravated by the nocturnal migration of the parasites. The oxyuris may traverse the intes- tinal wall, and has been found in the peritoneal cavity, where they may form verminous tubercles in Douglas's fossa or peri-rectal abscesses.
The patients become extremely restless and irritable, the sleep is often disturbed, and there may be loss of appetite and ansemia. Though most common in children, the parasite occurs at all ages.
The worm is readily detected in the faeces. Infection probably takes place through the water, or possibly through salads, such as lettuce and cresses. A person the subject of the worms passes ova in large numbers in the faeces, and the possibility of reinfection must be scrupulously guarded against.
The treatment is simple, though occasionally there are instances in which all forms of medication are resisted. A case is mentioned of a gentleman, aged forty, who had suffered from childhood and had failed to obtain any benefit from prolonged treatment by many helminthologists. Santonin may be used in small doses, and mild purgatives, particularly rhubarb. Large injections containing carbolic acid, vinegar, quassia, aloes, or turpentine may be employed. In children the use of cold injections of strong salt and water is usually efficacious. They should be repeated for at least ten days. In giving the injection care should be taken to have the hips well elevated, so that the fluid can be retained as long as possible. For the intense itching and irritation at night, vaseline may be freely used, or belladonna ointment. The " cat " ascaris and the " dog " ascaris are occasional parasites in man.
II. TRICHINIASIS.
The Trichina spiralis in its adult condition lives in the small intestine. The disease is produced by the embryos, which pass from the intestines and reach the voluntary muscles, where they finally become encapsulated larvae — ■
40 DISEASES DUE TO ANIMAL PARASITES.
muscle trichina. It is in the migration of the embryos (possibly from poisons produced by them) that the group of symptoms known as trichiniasis is produced.
The ovoid cysts were described in human muscle by Tiedemann in 1833, and by Hilton in 1833; the parasite was figured and named by Kichard Owen. Leidy in 1845 described it in the pig. For a long time the trichina was looked upon as a pathological curiosity; but in 1860 Zenker discovered in a girl in the Dresden Hospital, who had sjonptoms of typhoid fever, both the intestinal and muscle forms, and established their connection with a serious and often fatal disease.
Description of the Parasites. — (a) Adult or intestinal form. The female measures from 3 to 4 mm.; the male, 1.5 mm., and has two little projections from the hinder end.
(b) The larva or muscle trichina is from 0.6 to 1 mm. in length and lies coiled in an ovoid capsule, which is at first translucent, but subsequently opaque and infiltrated with lime salts. The worm presents a pointed head and a somewhat rounded tail.
When flesh containing the trichinse is eaten by man or by any animal in which the development can take place, the capsules are digested and the trichinas set free. They pass into the small intestine, and about the third day attain their full growth and become sexually mature. Virchow's experi- ments have shown that on the sixth or seventh day the embryos are fully developed. The young produced by each female trichina have been estimated at several hundred. Leuckart thinks that various broods are developed in succession, and that as many as a thousand embryos may be produced by a single worm. The time from the ingestion of the flesh containing the muscle trichina to the development of the brood of embryos in the intestines is from seven to nine days. The female worm penetrates the intestinal wall and the embryos are probably discharged directly into the IjTnph spaces (Askanazy), thence into the venous system, and by the blood stream to the muscles, which constitute their seat of election. J. Y. Graham reviewed the question of the mode of transmission in an exhaustive monograph, and he gives strong argu- ments in favor of the transmission through the blood stream. After a pre- liminary migration in the intermuscular connective tissue they penetrate the primitive muscle-fibres, and in about two weeks develop into the full-grown muscle form. In this process an interstitial myositis is excited and gradually an ovoid capsule develops about the parasite. Two, occasionally three or four, worms may be seen within a single capsule. This process of encapsulation has been estimated to take about six weeks. Within the muscles the parasites do not undergo further change. Gradually the capsule becomes thicker, and ultimately lime salts are deposited within it. This change may take place in man within four or five months. In the hog it may be deferred for many years. The calcification renders the cyst visible, and since first seen by Tiede- mann and Hilton, these small, opaque, oat-shaped bodies have been familiar objects to demonstrators of normal and morbid anatomy. The trichina may live within the muscles for an indefinite period. They have been found alive and capable of developing as late as twenty or even twenty-five years after their entrance into the system. In many instances, however, the worms are completely calcified. The trichina has been found or " raised " in twenty-six
DISEASES CAUSED BY NEMATODES. 41
different species of animals (Stiles). Medical literature abounds in refer- ences to its presence in fish, earthworms, etc., but these parasites belong to other genera. In fsecal examinations for the parasite it is well to remember that the " cell body " of the anterior portion of the intestine is a diagnostic criterion of the T. spiralis. Experimentally, guinea-pigs and rabbits are read- ily infected by feeding them with muscle containing the larval form. Dogs are infected with difficulty ; cats more readily. Experimentally, animals some- times die of the disease if large numbers of the parasites have been eaten. In the hog the trichinae, like the cysticerci, cause few if any symptoms. An animal the muscles of which are swarming with living trichinge may be well nourished and healthy-looking. An important point also is the fact that in the hog the capsule does not readily become calcified, so that the parasites are not visible as in the human muscles.
Incidence. — Man is infected by eating the flesh of trichinous hogs. In Germany, where a thorough and systematic microscopic examination of all swine flesh is made, the proportion of trichinous hogs is about 1 in 1,852. At the Berlin abattoir, where the microscopic examination is conducted by a staff of over eighty men and women, two portions are taken from the abdom- inal muscles, from the diaphragm, and from the intercostal muscles, and one piece from the muscles of the larynx and tongue. A special compressor is used to flatten the fragments of the muscle, and the examination is made with a magnifying power of from 70 to 100 diameters. Statistics are not available in England. In America inspections have been made since 1893. The percentage of animals found infected has ranged from 1.04 to 1.95.
In- 1883, in conjunction with A. W. Clement, I examined 1,000 hogs at the Montreal abattoir, and found only 4 infected.
Modes of Infection. — The danger of infection depends entirely upon the mode of preparation of the flesh. Thorough cooking, so that all parts of the meat reach the boiling point, destroys the parasites ; but in large joints the central portions are often not raised to this temperature. The frequency of the disease in different countries depends largely upon the habits of the people in the preparation of pork. In North Germany, where raw ham and Wurst are freely eaten, the greatest number of instances have occurred. In South Germany, France, and England cases are rare. In the United States the greatest number of persons attacked have been Germans. Salting and smoking the flesh are not always sufficient, and the Havre experiments showed that animals are readily infected when fed with portions of the pickled or the smoked meat as prepared in America. Carl Fraenkel, however, states that the experiments on this point have been negative, and that it is very doubtful if any cases of trichiniasis in Germany have been caused by Amer- ican pork. Germany has yet to show a single case of trichiniasis due to pork of unquestioned American origin.
Frequency of Infection. — H. U. Williams, of Buffalo, made a thorough study of the muscle from 505 unselected autopsies, and found 27 cases of trichiniasis, 5.3 per cent. The subjects had all died of causes other than trichiniasis. This important study shows how wide-spread is the disease, and that in reality we frequently overlook the sporadic form, a mistake which is now less often made, owing to T. E. Brown's discovery of the associated eosinophilia.
42 DISEASES DUE TO AXIMAL PARASITES.
The disease often occurs in epidemics, a large number of persons being infected from a single source. Among the best known of these, one occurred at Hedersleben, in which there were 337 persons affected, and another at Emersleben, in which there were 250 persons attacked. The extensive out- breaks of this sort have been, with few exceptions, in jSTorth Germany, and they are a comment on the inefficiency of the inspection. The statistics on the subject in the United States by Alfred Mann, by the late F. A. Packard, of Philadelphia, and more exhaustively by C. W. Stiles, who states that up to 1893 there was a total of 709 cases; since then he says, in a letter, 1898, there have been 40 or 50 cases reported. He thinks that 900 would cover the total number reported to that date. According to States, New York heads the list with 129 cases; Illinois shows 119; Massachusetts, 115; Iowa, 108, Xo doubt many cases escape detection, and the disease is not very un- common. The sporadic cases are often overlooked. Seven cases occurred in my wards within a few years.
Symptoms. — The ingestion of trichinous flesh is not necessarily followed by the disease. When a limited number are eaten only a few embryos pass to the muscles and may cause no symptoms. Well-characterized cases present a gastro-intestinal period and a period of general infection.
In the course of a few days after eating the infected meat there are signs of gastro-intestinal disturbance — pain in the abdomen, loss of appetite, vomit- ing, and sometimes diarrhoea. The preliminary symptoms, however, are by no means constant, and in some of the large epidemics cases have been ob- served in which they have been absent. In other instances the gastro-intestinal features have been marked from the outset, and the attack has resembled cholera nostras. Pain in different parts of the body, general debility, and weakness have been noted in some of the epidemics.
The invasion s^Tuptoms occur betAveen the seventh and the tenth day, sometimes not until the end of the second week. There is fever, except in very mild cases. Chills are not common. The thermometer may register 102° or 104°, and the fever is usually remittent or intermittent. The migra- tion of the parasites into the muscles excites a more or less intense myositis, which is characterized by pain on pressure and movement, and by swelling and tension of the muscles, over which the skin may be oedematous. The limbs are placed in the positions in which the muscles are in least tension. The involvement of the muscles of mastication and of the larynx may cause diffi- cult)' in chewing and swallowing. In severe cases the involvement of the dia- phragm and intercostal muscles may lead to intense dyspnoea, which sometimes proves fatal. CEdema, a feature of great importance, may be early in the face, particularly about the eyes. Later it occurs in the extremities when the swell- ing and stiffness of the muscles are at their height. Profuse sweats, tingling and itching of the skin, and in some instances urticaria, have been described.
Blood. — A marked leucoc}i:osis, which may reach above 30.000, is present. A special feature is the extraordinary increase in the number of eosinophilic cells, which may comprise more than 50 per cent of all the leucocytes. There were in four years, in the Jolins Hopkins Hospital, 7 cases in which this eosin- ophilia was most pronounced. In 4 of them the diagnosis was actually sug- gested by the great increase in the eosinophiles ; in 1 case they reached 68 per cent of the total number of leucocytes.
DISEASES CAUSED BY NEMATODES. 43
The general nutrition is much disturbed and the patient becomes emaci- ated and often anaemic, particularly in the protracted cases. The patellar tendon reflex may be absent. The patients are usually conscious, except in cases of very intense infection, in which the delirium, dry tongue, and tremor give a picture suggesting typhoid fever. In addition to the dyspnoea present in the severer infections, there may be bronchitis, and in the fatal cases pneu- monia or pleurisy. In some epidemics polyuria has been a common symptom. Albuminuria is frequent.
The intensity and duration of the symptoms depend entirely upon the grade of infection. In the mild cases recovery is complete in from ten to fourteen days. In the severe forms convalescence is not established for six or eight weeks, and it may be months before the patient recovers the muscular strength. One case in the Hedersleben epidemic was weak eight years after the attack.
Of 73 fatal cases in the Hedersleben epidemic, the greatest mortality oc- curred in the fourth and fifth and sixth weeks ; namely, 53 cases. Two died in the second week with severe choleraic symptoms.
The mortality has ranged in difl:erent outbreaks from 1 or 3 per cent to 30 per cent. In the Hedersleben epidemic 101 persons died. Among 456 cases reported in the United States there were 133 deaths.
The anatomical changes are chiefly in the voluntary muscles. The tri- chinae enter the primitive muscle bundles, which undergo granular degenera- tion with marked nuclear proliferation. There is a local myositis, and gradually about the parasite a cyst wall is formed. These changes, as well as the remarkable alterations in the blood, have been described in full by Thomas R. Brown. Cohnheim has described a fatty degeneration of the liver and enlargement of the mesenteric glands. At the time of death in the fourth or fifth week or later, the adult trichinae are still found in the intestines.
The prognosis depends much upon the quantity of infected meat which has been eaten and the number of trichinae which mature in the intestines. In children the outlook is more favorable. Early diarrhoea and moderately intense gastro-intestinal symptoms are, as a rule, more favorable than con- stipation.
Diagnosis. — The disease should always be suspected when a large birth- day party or Fest among Germans is followed by cases of apparent typhoid fever. The parasites may be found in the remnants of the ham or sausages used on the occasion. The worms may be discovered in the stools. The stools should be spread on a glass plate or black background and examined with a low-power lens, when the trichinas are seen as small, glistening, silvery threads. In doubtful cases the diagnosis may be made by the removal of a small frag- ment of muscle. A special harpoon has been devised for this purpose, by means of which a small portion of the biceps or of the pectoral muscle may be readily removed. Under cocaine anaesthesia an incision may be made and a small fragment removed. The disease may be mistaken for acute rheuma- tism, particularly as the pains are so severe on movement, but there is no special swelling of the joints. The great increase in the eosinophiles in the blood is, as mentioned above, a most suggestive point in diagnosis. The tenderness is in the muscles both on pressure and on movement. The intensity
44 DISEASES DUE TO ANIMAL PARASITES.
of the gastro-intestinal symptoms in some cases has led to the diagnosis of cholera. Many of the former epidemics were doubtless described as typhoid fever, which the severer cases, owing to the prolonged fever, the sweats, the delirium, dry tongue, and gastro-intestinal symptoms, somewhat resemble. The pains in the muscles, with tension and swelling, oedema, particularly about the eyes, and shortness of breath, are the most important diagnostic points.
Prophylaxis. — It is not definitely known how swine become diseased. It has been thought that they are infected from rats about slaughter-houses, but it is just as reasonable to believe that the rats are infected by eating portions of the trichinous flesh of swine. The swine should, as far as possible, be grain-fed, and not, as is so common, allowed to eat offal. The most satis- factory prophylaxis is the complete cooking of pork and sausages, and to this custom in England, France, South Germany, and the United States, immu- nity is largely due.
Treatment. — If it has been discovered within twenty-four or thirty-six hours that a large number of persons have eaten infected meat, the indications are to thoroughly evacuate the gastro-intestinal canal. Purgatives of rhubarb and senna may be given, or an occasional dose of calomel. Glycerin has been recommended in large doses, in order that by pa^ssing into the intestines it may by its hygroscopic properties destroy the worm. Male-fern, kamala, santonin, and thymol have all been recommended in this stage. Turpentine may be tried in full doses. There is no doubt that diarrhoea in the first week or ten days of the infection is distinctly favorable. The indications in the stage of invasion are to relieve the pains, to secure sleep, and to support the pa- tient's strength. There are no medicines which have any influence upon the embryos in their migration through the muscles.
III. ANKYLOSTOMIASIS.
(Uncinariasis ; Hook- Worm Disease ; Miner's Ansemia ; Egyptian Chlorosis, etc.)
History. — In 1843 Dubini first described the hook-worm in man. Grie- singer demonstrated its connection with the Egyptian chlorosis, a disease which Sandwith states is mentioned by the old Egyptian writers of between three and four thousand years ago. Subsequently the disease was described in the tunnel-workers at St. Gothard, and from this time on has been recog- nized as an important cause of tropical anaemia and the anaemia of miners, brick-workers, and tunnel-workers.
Incidence. — The parasite is widely spread in tropical and subtropical countries, and is one of the most fatal of all parasitic diseases. In Porto Eico, in 1906-7 more than 89,000 cases were treated by the permanent com- mission. An attempt is being made to stamp out the disease, which causes thousands of deaths, usually by a progressive anaemia with anasarca. While it was known that a few cases occurred in the United States, it was not until the interest aroused in tropical diseases by the Spanish-American War and the work of Ashf ord in Porto Eico that the attention of American physicians was called to the disease. Eeports of cases were published in 1901 and 1902, and in the latter year Stiles took up the study of the problem and dem^onstrated to
DISEASES CAUSED BY NEMATODES. 45
the astonishment of the profession that the disease was endemic in many places, and was tlie cause of the common anasmia of the Southern States. It has been found among the miners in Pennsylvania, but fortunately not to any great extent. In the Philippines it is not uncommon. Among the miners of Germany and Austro-Hungary the disease has increased very much of late years. The disease is very prevalent in Westphalia. During the year 1903, 3,000 patients were treated for ankylostomiasis in the Bochum Hospital. In England much interest was aroused in the discovery by Haldane that the ansemia of the Cornish miners was due to the ankylostoma. In Egypt the dis- ease is very prevalent, not . only among the natives, but among the Indian coolies. The superb monograph of Loos of the Government school, Cairo, may be referred to for details of the biology of the parasite. It prevails extensively in Queensland.
Parasite. — The worm is a strongyle, occurring in two forms, the Old- World Ankylostoma duodenale and the New- World Uncinaria americana, de- scribed by Stiles. Loos and Stiles now believe that the American species should not be classed with Uncinaria, and the new name of Necator ameri- canus is suggested. The parasites have the same general characters ; the males are 7 to 11 mm. in length, the females 10 to 18 mm. The American worm is the longer, and has well-marked specific peculiarities. The mouth is provided with a heavy armature of sharp teeth, with which they pierce the mucosa of the bowel, and by means of a strong muscular oesophagus suck the blood. The male has a prominent caudal expansion or bursa. The eggs are 64 to 76 ^ by 36 to 40 /a in the American form, and 52 to 60 /* by 32 ju, in the Euro- pean form; they are laid in segmentation, forming very characteristic bodies in the faeces of infected persons.
The development is direct without an intermediate host. The embryo lives in the water or moist ground and passes through the rhabditiform stage. The mode of entrance into the body has been much discussed. The larvae may live for months in the mud and water of the mines. It may be taken into the body with the drinking-water or with the dirt from the hands of the miners and tunnel-workers, or in the soil deliberately eaten in some instances by the earth feeders — the geophagi — in the Southern States. Loos showed that the embryo worms readily enter the skin and are carried by the veins to the right side of the heart and to the lungs. Escaping from the pulmonary ves- sels into the air spaces, they pass up the bronchi and trachea to the pharynx and so down the gullet to the stomach and intestines. These remarkable obser- vations of Loos have been confirmed by Schaudinn. Bentley, Allen J. Smith, and others have suggested that the " ground-itch " of the tropics, a peculiar form of dermatitis, may be due to the penetration of the skin by the anky- lostoma embryos, and Boycott and Haldane think that the skin eruption known as the " bunches " in the Cornish miners may be associated with the entrance of the worms.
The adult worm lives in the small intestine, chiefly in the jejunum, but it may be found in the duodenum or in the colon, rarely in the stomach. The duration of life in the bowel has not been determined. It is probably a matter of years. The liability to reinfection is of course very great.
Symptoms. — The following factors, referred to by Stiles in his monograph (Hygienic Laboratory Bulletin, No. 10, Washington, 1903), have to be con-
46 DISEASES DUE TO ANIMAL PARASITES.
sidered: The constant drain on the system by the sucking of blood can no longer as formerly be regarded as the chief cause of the anaemia. Through the wounds bacterial infection may take place; the wall of the bowel may be much thickened and degenerated, so that its functions are interfered with; and, lastly, it is quite possible that toxic substances are produced by the para- sites which act injuriously upon the patient. Blood is rarely found in the stools.
A considerable number of parasites must be present to cause any symp- toms. The investigations of many physicians in the Southern States have shown that in some districts a very considerable percentage of even compara- tively healthy children have the ova in the stools. Among miners the anaemia may be absent, as sho-woi by the studies of Haldane and. Boycott in Cornwall. Stiles groups the cases into the three divisions of light, medium, and severe. At the onset in the stage of incubation there may be gastro-intestinal irrita- tion, and, according to Sandwith, fever. In the advanced condition anaemia is the most characteristic feature. The skin is of a dirty, muddy hue, some- times of a waxy white color. In the Southern States it is known as the Florida complexion. There is a lack of lustre in the eyes and a dull, heavy expression, and Stiles tliinks there is something very characteristic about the blank, lack-lustre stare in this disease. In children there is much interfer- ence in the growth, so that they are stunted and ill-developed. As the dis- ease advances and the anemia becomes more pronounced, the liver and the spleen become somewhat enlarged, and there is an effusion into the abdomen, so that there is a pot-bellied condition, due partly to the causes just men- tioned and partly to the flatulent distention. OEdema of the feet is not uncommon. The cardio-vascular features are those of severe anaemia — palpi- tation, shortness of breath, cardiac bruits. In a very characteristic case in my wards from Xorth Carolina, in which the blood was carefully studied by Boggs, the red blood-corpuscles were 2,742,000, hasmoglobin 37 per cent, leucocytes 55,000. The differential count gave pol}Tiuclear neutrophiles 51.8; small mononuclears 26.4; large mononuclears 15.4; eosinophiles 4.6; mast- cells 1.8. The eosinophilia is a most important feature of the disease, being present in 94 per cent of the cases (Boycott and Haldane).
Diagnosis. — The diagnosis is very simple. The eggs are characteristic. It is well to examine the stools after the use of the thjTnol. Stiles states that the blotting-paper test is useful when a microscopical examination can not be made. A portion of the faeces is placed upon white blotting- paper, and if allowed to stand for about an hour there is a reddish- bro-^Ti staiu suggestive of blood. Eosinophilia is a most valuable diag- nostic sign.
Some idea of the intensity of the infection may be gained by the number of ova in the cubic centimetre of faeces. Grasse, quoted by Manson, states that from 150 to 180 eggs per cubic centimetre indicates an infection of about 1,000 worms.
Prophylaxis. — In the rural districts of the Southern States the disease is associated with the absence of proper sanitary conditions, particularly latrines, etc. The infection is more common in the summer than in the win- ter, and whites appear to be relatively more frequently attacked than the blacks. In infected regions the wearing of shoes should be made compulsory.
DISEASES CAUSED BY NEMATODES. 47
The prophylaxis in miners is an important national problem. New miners should j)ass a careful medical examination. Infected miners before resuming work should present a certificate of freedom from the disease. Each working colliery should provide suitable closet accommodation, in infected mines, 1 to every 20 men of the total staff. They are to be emptied and disinfected daily. These regulations, adopted in Hungary, as given by Oliver, will do much to limit the spread of the disease.
Prognosis. — The prognosis is good, except in the advanced cases of anae- mia. The figures already stated from Porto Rico indicate its fatality under suitable conditions. Ashford and King estimate that at least 30 per cent of the deaths are due to it.
Treatment. — After a few days' preliminary dieting the patient is given half a drachm of thymol, repeated in two hours, and then two hours later a dose of castor oil. Sandwith states that about a drachm of thymol in the twenty-four hours is perfectly efficacious. He recommends giving the thymol in brandy or whisky. In very debilitated patients it should be given in smaller doses and over a longer period. The stools should be carefully examined at intervals of a few days, and the treatment should be repeated if the ova are still present. The worms are not always easy to destroy. Male-fern may be given in doses of from a drachm to two drachms, followed by a saline purge. The general treatment is that of anaemia.
IV. FILARIASIS.
For a full discussion of the zoological relations of this important group, see Stiles' article in my " System of Medicine,'.' Vol. I.
Under the general term Filaria sanguinis Jiominis three species of nema- todes are included:
Filaria bancrofti, Cobold, 1877. This is the ordinary blood filaria. The embryos are found in the peripheral circulation only during sleep or at night. The mosquito is the intermediate host. The embryos measure 270 to 340 fi long by 7 to 11 /I. broad ; tail pointed. The adult male measures 83 mm. long by 0.407 mm. broad ; the tail forms two turns of a spiral. The adult female measures 155 mm. long by 0.715 mm. broad; vulva 2.56 nun. from anterior extremity; eggs 38 fi by 14 ju,. This is the species to which the haematochy- luria and elephantiasis are attributed.
Filaria diurna, Manson, 1891. The larvs agree with the preceding, except that Manson indicates the absence of granules in the axis of the body. The worms occur in the peripheral circulation only during the day, or when the patient stays awake. Manson suspects that the Filaria loa represents the adult stage.
Filaria perstans, Manson, 1891. Only the embryos are known. These are much smaller than the preceding — 200 yu long, posterior extremity obtuse, anterior extremity with a sort of retractile rostellum.
Manson is inclined to regard the Filaria perstans as the cause of craw- craw, a papillo-pustular skin eruption of the west coast of Africa, which is probably the same as Nielly's dcrmatose parasitaire, the parasite of which was called by Blanchard Rhahditis Nielhji. Manson has shown that in the blood of the aboriginal Indians in British Guiana there are two forms of filarial
48 DISEASES DUE TO ANIMAL PARASITES.
embryos which differ somewhat from the ordinary types. Daniels and Ozzard have shown the extraordinary prevalence of these parasites in the aborigines — fully 58 per cent. Daniels has found the mature filariae in two subjects in the upper part of the mesentery, near the pancreas and in the subpericardial fat.
The most important of these is the Filaria Bancrofti, which produces the haematochyluria and the lymph-scrotum.
The female produces an extraordinary number of embryos, which enter the blood current through the lymphatics. Each embryo is within its shell, which is elongated, scarcely perceptible, and in no way impedes the movements. They are about the ninetieth part of an inch in length and the diameter of a red blood-corpuscle in thickness, so that they readily pass through the capillaries. They move with the greatest activity, and form very striking and readily recognized objects in a blood-drop under the microscope. A remark- able feature is the periodicity in the occurrence of the embryos in the blood. In the daytime they are almost or entirely absent, whereas at night, in typical cases, they are present in large numbers. If, however, as Stephen Mackenzie has shown, the patient, reversing his habits, sleeps during the daj^, the peri- odicity is reversed. In the case reported by Lothrop and Pratt the number of embryos per cubic centimetre of blood was calculated hourly during the night; it rose steadily from four o'clock in the afternoon till midnight, when 3,100 per c.cm. were present, then fell, none being found at ten o'clock the following morning. The further development of the embryos is associated with the mosquito, which at night sucks the blood and in this way frees them from the body. After developing a little it was thought that they were set free in the water by the death of the host. S. P. James has found them in the tissues of the proboscis of the mosquito, and the infection is probably direct, as in malaria. The filariae may be present in the body without causing any symptoms. In the blood of animals filariee are very common and rarely cause inconvenience. It is only when the adult worms or the ova block the lymph channels that certain definite symptoms occur, Manson suggests that it is the ova (prematurely discharged), which are considerably shorter and thicker than the full-grown embryos, which block the lymph channels and pro- duce the conditions of haematochyluria, elephantiasis, and lymph-scrotum.
The parasite is widely distributed, particularly in tropical and subtropical countries. Guiteras has shown that the disease prevails extensively in the Southern States, and since his paper appeared contributions have been made by Matas, of New Orleans, Mastin, of Mobile, De'Saussure, of Charleston, and Opie.
The effects produced may be described under the following conditions:
1. H^MATOCHYLURiA. — Without any external manifestations, and in many cases without special disturbance of health, the subject from time to time passes urine of an opaque white, milky appearance, or bloody, or a chy- lous fiuid which on settling shows a slightly reddish clot. The urine may be normal in quantity or increased. The condition is usually intermittent, and the patient may pass normal urine for weeks or months at a time. Micro- scopically, the chylous urine contains minute molecular fat granules, usually red blood-corpuscles in various amounts. The embryos were first discovered by Demarquay, at Paris (1863), and in the urine by Wucherer, at Bahia, in 1866. It is remarkable for how long the condition may persist without seri-
. DISEASES CAUSED BY NEMATODES. 49
ous impairment of the health. A patient, sent to me by Dawson, of Charles- ton, has had hsematochyluria intermittently for eighteen years. The only inconvenience has been in the passage of the blood-clots which collect in the bladder. At times he has also uneasy sensations in the lumbar region. The embryos are present in his blood at night in large numbers. Chyluria is not always due to, the filaria. The non-parasitic form of the disease is considered elsewhere.
Opportunities for studying the anatomical condition of these cases rarely occur. In the case described by Stephen Mackenzie the renal and peritoneal lymph plexuses were enormously enlarged, extending from the diaphragm to the pelvis. The thoracic duct above the diaphragm was impervious.
2. Lymph-Scrotum and certain forms of elephantiasis are also caused by the filaria. In the former the tissues of the scrotum are enormously thickened and the distended lymph-vessels may be plainly seen. A clear, sometimes a turbid, fluid follows puncture of the skin. The question of the relation of filarise to the forms of tropical elephantiasis has been reopened, and it seems doubtful if all depend upon filarise.
Treatment. — So far as I know, no drug destroys the embryos in the blood. In infected districts the drinking-water should be boiled or filtered. In cases of chyluria the patients should use a dry diet and avoid all excess of fat. The chyle may disappear quite rapidly from the urine under these meas- ures, but it does not necessarily indicate that the case is cured. So long as clots and albumin are present the leak in the lymphoid varix is not healed, although the fat, not being supplied to the chyle, may not be present. A single tumblerful of milk will at once give ocular proof of the patency or otherwise of the rupture in the varix (Manson).
The surgical treatment of some of these cases is most successful, particu- larly in the removal of the adult filarise from the enlarged lymph-glands, especially in the groin. Maitland states that during seven years 25 opera- tions of this kind have been performed without serious symptoms. In a case of Primrose's, of Toronto, the parasites were absent from the blood six and a half months after operation.
V. DRACONTIASIS (Guinea-worm Disease).
The Filaria or Dracunculus medinensis is a widely spread parasite in parts of Africa and the East Indies. In the United States instances occa- sionally occur. Jarvis reports a case in a post chaplain who had lived at Fortress Monroe, Va., for thirty years. Van Harlingen's patient, a man aged forty-seven, had never lived out of Philadelphia, so that the worm must be included among the parasites of this country. A majority of the cases reported in American journals have been imported.
Only the female is known. It develops in the subcutaneous and inter- muscular connective tissues and produces vesicles and abscesses. In the large majority of the cases the parasite is found in the leg. Of 181 cases, in 124 the worm was found in the feet, 33 times in the leg, and 11 times in the thigh. It is usually solitary, though there are cases on record in which six or more have been present. It is cylindrical in form, about 2 mm. in diameter, and from 50 to 80 cm. in length.
50 DISEASES DUE TO ANIMAL PARASITES.
The worm gains entrance to the system through the stomach, not through the skin, as was formerly supposed. It is probable that both male and female are ingested; but the former dies and is discharged, while the latter after impregnation penetrates the intestine and attains its full development in the subcutaneous tissues, where it may remain quiescent for a long time and can be felt beneath the skin like a bundle of string. The worm con- tains an enormous number of living embryos, and to enable them to escape she travels slowly downward head first, and, as mentioned, usually reaches the foot or ankle. The head then penetrates the skin and the epidermis forms a little vesicle, which ruptures, and a small ulcer is left, at the bottom of which the head often protrudes. The distended uterus ruptures and the embryos are discharged in a whitish fluid. After getting rid of them the worm will spontaneously leave her host. In the water the embryos develop in the cyclops — a small crustacean — and it seems likely that man is infected by drinking the water containing these developed larvae.
When the worm first appears it should not be disturbed, as after par- turition she may leave spontaneously. When the worm begins to come out a common procedure is to roll it round a portion of smooth wood and in this way prevent the retraction, and each day wind a little more until the entire worm is withdrawn. It is stated that special care must be taken to prevent tearing of the worm, as disastrous consequences sometimes follow, probably from the irritation caused by the migration of the embryos.
The parasite may be excised entire, or killed by injections of bichloride of mercury (1 to 1,000). It is stated that the leaves of the plant called amarpattee are almost a specific in the disease. Asafcetida in full doses is said to kill the worm.
In East Africa Kolb states that he found in the abdominal cavity of a recently killed native Massai several large nematode worms believed to be allied to the filaria medinensis. He thinks this parasite is possibly asso- ciated with what is known as the Massai disease, characterized by attacks of fever lasting some three days, with tenderness of the abdomen and vomit- ing. Kolb thinks that in these cases the filariae which have become encysted about the liver " as a normal event in their life history burst their cysts, the contents escaping into the peritoneal cavity, thereby giving rise to the symp- toms." The subject is one which requires further investigation.
VI. OTHER NEMATODES.
Filariae. — Among less important filarian worms parasitic in man the following may be mentioned : Filaria loa, which is a cylindrical worm of about 3 cm. in length and whose habitat is beneath the conjunctiva. It has been found on the West African coast, in Brazil, and in the West Indies. Filaria lentis, which has been found in a cataract. Three specimens have been found together. Filaria lahialis, which has been found in a pustule in the upper lip. Filaria liominis oris, which was described by Leidy, from the mouth of a child. Filaria hroncliialis, which has been found occasion- ally in the trachea and bronchi. This parasite has been seen in a few cases in the bronchioles and in the lungs. There is no evidence that it ever produces an extensive verminous bronchitis similar to that which I haye
DISEASES CAUSED BY NEMATODES. 51
described in dogs. Filaria i7nmitis — the common Filaria sanguinis of the dog — of which Bowlby has described two cases in man. In one case with haeraaturia female worms were found in the portal vein, and the ova were present in the thickened bladder wall and in the ureters.
Trichocephalus dispar (Whip- worm). — This parasite is not infrequently found in the csecum and large intestine of man. It measures from 4 to 5 cm. in length, the male being somewhat shorter than the female. The worm is readily recognized by the remarkable difference between the anterior and posterior portions. The former, which forms at least three fifths of the body, is extremely thin and hair-like in contrast to the thick hinder por- tion of the body, which in the female is conical and pointed, and in the male more obtuse and usually rolled like a spring. The eggs are oval, lemon- shaped, 0.05 mm. in length, and each is provided with a button-like pro- jection.
The number of the worms found is variable, as many as a thousand hav- ing been counted. It is a widely spread parasite. In parts of Europe it occurs in from 10 to 30 per cent of all bodies examined, but in the United States it is not so common. The trichocephalus rarely causes symptoms. French and Boycott found ova in 40 of 500 Guy's Hospital patients. They found no etiological relationship of the parasite to appendicitis. Several cases have been reported in which profound anaemia has occurred in connection with this parasite, usually with diarrhoea. Enormous numbers may be pres- ent, as in Eudolph's case, without producing any symptoms.
The diagnosis is readily made by the examination of the faeces, which con- tain, sometimes in great abundance, the characteristic lemon-shaped, hard, dark-brown eggs.
Dicotophyme gigas (Eustrongylus gigas). — This enormous nematode, the male of which measures about a foot in length and the female about three feet, occurs in very many animals and has occasionally been met with in man. It is usually found in the renal region and may entirely destroy the kidney.
Anguillula aceti. — The Anguillula aceti, or vinegar eel, is sometimes present in the urine (in one case it is said from the bladder). It is most probably a contamination from a dirty bottle in which the urine is col- lected.
Strongyloides intestinalis. — ^Under this name are now included the small nematode worms found in the faeces and formerly described as Anguillula stercoralis, Anguillula intestinalis, and Rhahdonema intestinale. This para- site occurs abundantly in the stools of the endemic diarrhoea of hot countries, and has been specially described by the French in the diarrhoea of Cochin- China. It has been found in Manila by Strong, and three cases have been reported from my clinic by W. S. Thayer. It is stated that the worms occupy all parts of the intestines, and have even been found in the biliary and pan- creatic duets. It is only when they are in very large numbers that they pro- duce severe diarrhoea and anaemia.
Acanthocephala (Thorn-headed Worms). — The Gigantorhynchus or Echinorhynclius gigas is a common parasite in the intestine of the hog and attains a large size. The larvae develop in cockchafer grubs. The Ameri- can intermediate host is the June bug (Stiles). Lambl found a small
52 DISEASES DUE TO ANIMAL PARASITES.
Echinorhynclius in the intestine of a boy. Welch's specimen, which was found encysted in the intestine of a soldier at Netley, is stated by Cobbold probably not to have been an Echinorhynclius. Eecently a case of Echino- rhynchus moniliformis has been described in Italy by Grassi and Calandruccio.
F. PARASITIC ARACHNIDA AND TICKS.
Pentastomes. — 1. Lixguatula ehinaria {Pentastoma tcenioides) has a somewhat lancet-shaped body, the female being from 3 to 4 inches in length, the male about an inch in length. The body is tapering and marked by numerous rings. The adult worm infests the frontal sinuses and nostrils of the dog, more rarely of the horse. The larval form, which is known as the Linguatula serrata {Pentastomum denticulatum) , is seen in the internal organs, particularly the liver, but has also been found in the kidney. The adult worm has been f OTind in the nostril of man, but is very rare and seldom occasions any inconvenience. The larvae are by no means uncommon, par- ticularly in parts of Germany.
2. The Poeocephalus con"STRICTUS (Pentastomum constrictum), which is about the length of half an inch, with twenty-three rings on the abdomen, was found by Aitken in the liver and lungs of a soldier of a West Indian regiment.
The parasite is very rare. Flint refers to a Missouri case in which from 75 to 100 of the parasites were expectorated. The liver was enlarged and the parasites probably occupied this region. In 1869 I saw a specimen which had been passed with the urine by a patient of James H. Eichardson, of Toronto.
Demodex (Acarus) folliculomni (var. hominis). — A minute parasite, from 0.3 mm. to 0.4 mm. in length, which lives in the sebaceous follicles, particu- larly of the face. It is doubtful whether it produces any s5anptoms. Pos- sibly when in large numbers they may excite inflammation of the follicles, leading to acne.
Sarcoptes (Acarus) scabiei (Itch Insect). — This is the most important of the arachnid parasites, as it produces troublesome and distressing skin eruptions. The male is 0.23 mm. in length and 0.19 mm. in breadth; the female is 0.45 mm. in length and 0.35 mm. in width. The female can be seen readily with the naked eye and has a pearly-white color. It is not so common a parasite in the United States and Canada as in Europe.
The insect lives in a small burrow, about 1 cm. in length, which it makes for itself in the epidermis. At the end of this burrow the female lives. The male is seldom found. The chief seat of the parasite is in the folds where the skin is most delicate, as in the web between the fingers and toes, the backs of the hands, the axilla, and the front of the abdomen. The head and face are rarely involved. The lesions which result from the presence of the itch insect are very numerous and result largely from the irritation of the scratching. The commonest is a papular and vesicular rash, or, in children, an ecthymatous eruption. The irritation and pustulation which follow the scratching may completely destroy the burrows, but in typical cases there is rarely doubt as to the diagnosis.
PARASITIC INSECTS. 53
The treatment is simple. It should consist of warm haths with a thor- ough use of a soft soap, after which the skin should be anointed with sul- phur ointment, which in the case of children should be diluted. An oint- ment of naphthol (drachm to the ounce) is very efficacious.
Leptus autumnalis (Harvest Bug). — This reddish-colored parasite, about half a millimetre in size, is often found in large numbers in fields and in gardens. They attach themselves to animals and man with their sharp proboscides, and the hooklets of their legs produce a great deal of irritation. They are most frequently found on the legs. They are readily destroyed by sulphur ointment or corrosive-sublimate lotions.
Ixodiasis (Tick-fever). — In South Africa, particularly in the western provinces of the Uganda Protectorate, the western districts of German East Africa and the eastern regions of the Congo Free State, there is a disease known by this name, believed to be transmitted by a tick — the Ornithodorus or Argas moubata. Christy states that the bite of the 0. Savignyi does not produce any ill effects. The ticks live in old houses, and their habits are very much like those of the common bedbug. The symptoms are pains in the head, back and limbs, vomiting, fever and diarrhoea, which may last for from two to four weeks. Death may occur between the tenth and fifteenth days. A majority of the cases recover. A spirillum has been described in the blood by P. H, Eoss and Milne.
The Dermacentor occidentaUs is present in the Northwestern States from California to Montana. The bites may cause severe lymphangitis. It appears to be the medium of transmission of the Eocky Mountain spotted fever, which is described on p. 368.
In Arizona and other parts of the Southwestern States, a tick — Ornitho- dorus megnini — is occasionally found in the ear and in the nose, causing suppuration and intense suffering.
Several other varieties of ticks are occasionally found on man — ^the Ixodes ricinus and the Dermacentor Americanus, which are met with in horses and oxen.
G. PARASITIC INSECTS.
Pediculi (Phthiriasis; Pediculosis). — There are three varieties of the body louse, which are found only in persons of uncleanly habits.
Pediculus capitis. — The male is from 1 to 1.5 mm. in length and the female nearly 3 mm. The color varies somewhat with the different races of men. It is light gray with a black margin in the European, and very much darker in the negro and Chinese. They are oviparous, and the female lays about sixty eggs, which mature in a week. The ova are attached to the hairs, and can be readily seen as white specks, known popularly as nits. The symptoms are irritation and itching of the scalp. When numerous, the insects may excite an eczema or a pustular derma- titis, which causes crusts and scabs, particularly at the back of the head. In the most extreme cases the hair becomes tangled in these crusts and matted together, forming at the occiput a firm mass which is known as plica polonica, as it was not infrequent among the Jewish inhabitants of Poland.
54 DISEASES DUE TO AXLMAL PARASITES.
Pediculus coepoeis (vestimentorum) . — Tliis is considerably larger than the head louse. It lives on the clothing, and in sucking the blood causes minute hsemorrhagic specks, which are very common about the neck, back, and abdomen. The irritation of the bites may cause urticaria, and the scratching is usually in linear lines. In long-standing cases, particularly in old dissipated characters, the skin becomes rough and greatly pigmented, a condition which has been termed the vagabond's disease — morbus erronum — and which may be mistaken for the bronzing of Addison's disease. The pigmentation in some cases may be extreme and extend to the face and buccal mucosa.
Phthieius pubis differs somewhat from the other forms, and is found in the parts of the body covered with short hairs, as the pubes ; more rarely the axilla and eyebrows.
The taclies hJeuatres or peliomata, excited by the irritation of pediculi, are peculiar subcuticular bluish or slate-colored spots from 5 to 10 mm, in diam- eter seen about the abdomen and thighs, particularly in febrile cases. They are very well pictured in Murchison's work on Fevers. The spots are more marked on white thin skins. They are stains caused by a pigment in the secretion of the salivary glands of the louse. I have never seen these macuIcB ceruJecE, as they are also called, without finding the lice or their nits.
Treatment. — For the Pediculus capitis, when the condition is very bad, the hair should be cut short, as it is very difficult to destroy thoroughly all the nits. Eepeated saturations of the hair in coal-oil or in turpentine are usually efficacious, or with lotions of carbolic acid, 1 to 50. Scrupulous cleanliness and care are sufficient to prevent recurrence. In the case of the Pediculus corporis, the clothing should be placed for hours in a disinfecting oven. To allay the itching a warm bath containing 4 or 5 ounces of bicar- bonate of soda is useful. The skin may be rubbed with a lotion of carbolic acid, 2 drachms to the pint, with 2 ounces of glycerin. For the Phthirius pubis wliite precipitate or ordinary mercurial ointment should be used, and the parts should he thoroughly washed two or three times a day with soft soap and water.
Cimex lectularius (Common Bedbug). — The tropical and subtropical variety is Cimex rotundalius (W. S. Patton). It lives in the crevices of the bedstead and in the cracks in the floor and in the walls. It is nocturnal in its habits. The peculiar odor of the insect is caused by the secretion of a special gland. The parasite possesses a long proboscis, with which it sucks the blood. Individuals differ remarkably in the reaction to the bite of this insect: some are not disturbed in the slightest by them, in others the irrita- tion causes hyperemia and often intense urticaria. Fumigation with sul- phur or scouring with corrosive-sublimate solution or kerosene destroys them. Iron bedsteads should be used.
Pulex irritans (Commox Flea). — The male is from 2 to 2.5 mm. in length, the female from 3 to 4 mm. The flea is a transient parasite on man. The bite causes a circular red spot of hyperemia in the centre of which is a little speck where the boring apparatus has entered. The amount of irritation caused by the bite is variable. Many persons suffer intensely and a diffuse erythema or an irritable urticaria develops; others suffer no inconvenience whatever.
PARASITIC FLIES. 55
The Pulex penetrans (sand-flea; jigger) is found in tropical countries, particularly in the West Indies and South America. It is much smaller than the common flea, aud not only penetrates the skin, but burrows and produces an inflammation with' pustular or vesicular swelling. It most fre- quently attacks the feet. It is readily removed with a needle. Where they exist in large numbers the essential oils are used on the feet as a preventive.
H. PARASITIC FLIES.
MYIASIS (Myiosis).
The accidental invasion of the body cavities and of the skin by the larvag of the diptera is known as myiasis.
The larvae of the Lucilia macellaria, the so-called screw-worm, have been found in the nose, in wounds, and in the vagina after delivery. They can be removed readily with the forceps ; if there is any difficulty, thorough cleansing and the application of an antiseptic bandage is sufficient to kill them. The ova of the blue-bottle fly may be deposited in the nostrils, the ears, or the conjunctiva — the myiasis narium, aurium, conjunctivEe. This invasion rarely takes place unless these regions are the seat of the disease. In the nose and in the ear the larvae may cause serious inflammation. Even the urethra has not been spared in these dipterous invasions.
Gastro-intestinal myiasis may result from the swallowing of the larvae of the common house-fly or of species of the genus Antliomyia. There are many cases on record in which the larvge of the Musca domestica have been dis- charged by vomiting. Instances in which dipterous larvae have been passed in the fseces are less common. Finlayson, of Glasgow, has reported an inter- esting ease in a physician, who, after protracted constipation and pain in the back and sides, passed large numbers of the larvae of the flower-fly — Antliomyia canicularis. Among other forms of larvae or gentles, as they are sometimes called, which have been found in the faeces, are those of the com- mon house-fly, the blue-bottle fly, and the Techomyza fusca. The larvae of other insects are extremely rare. It is stated that the caterpillar of the taby moth has been found in the faeces.
A specimen of the Homalomyia scalaris, one of the privy flies, was sent to me by Dr. Hartin, of Kaslo City, British Columbia, the larvee of which were passed in large numbers in the stools of a man aged twenty-four, a native of Louisiana. They Were present in the stools from May 1 to July 15, 1897.
Although no grave results necessarily follow the invasion of the alimen- tary tract by these larvae, yet they may be the cause of serious intestinal ulcer- ation manifesting itself by a dysenteric disease with fatal result.
Cutaneous Myiasis. — The most common form of cutaneous myiasis is that in which an external wound becomes " living," as it is called. This myiasis vulnerum is caused by the larvae of either the blue-bottle or the common flesh-fly.
The skin may also be infected by the larvae of the Musca vomitoria, but more commonly by the bot-flies of the ox and sheep which occasionally attack man. This condition is rare in temperate climates. Matas has described a
56 DISEASES DUE TO ANIMAL PARASITES.
case in which oestrus larvse were found in the gluteal region. In parts of Central America the eggs of another bot-fly, the Dermatobia, are not infre- quently deposited in the skin and produce a swelling very like the ordi- nary boil.
Dermamyiasis linearis migrans CEstrosa is a remarkable cutaneous condi- tion, observed particularly in Eussia and occasionally in other countries, in which the larva of GastropMlus equi (Samson), the horse bot-fly, makes a slightly raised pale red " line " which travels over the body surface, sometimes with great rapidity. It has been referred to as Larva migrans and as Creep- ing Eruption. (See Hamburger, Journal of Cutaneous Disease.s, 1904.)
In Africa the larvas of the Cayor fly are not uncommonly found beneath the skin in little boils. In the Congo region. Button, Todd, and Christy found a troublesome blood-sucking dipterous