fM ;! 'x.k^ m m Hi:1 4* / / ELEMENTS GENERAL PATHOLOGY. ELEMENTS OF GENERAL PATHOLOGY. BY A. F. CHOMEL, PROFESSOR OP CLINICAL MEDICINE TO THE FACULTY OF PARIS J CONSULTING PHYSICIAN TO THE KING J PHYSICIAN IN ORDINARY TO THE PRINCESS ROYAL J OFFICER OF THE LEGION OF HONOR ; HONORARY PHYSICIAN OF THE HOSPITALS } MEMBER OF THE ROYAL ACADEMY OF MEDICINE J AND OF MANY OTHER ACADEMIES AND LEARNED SOCIETIES, NATIONAL AND FOREIGN. Melius est sistere gradum quam progredi per tenebras. — Gaubivs. THI.RD EDITION, CONSIDERABLY ENLARGED. TRANSLATED FROM THE FRENCH BY F. E OLIVER, M. D., AND W. W. MORLAND. M. D., Members of the Massachusetts Medical Society. BOSTON: WILLIAM D. TICKNOR AND COMPANY. CORNER OF WASHINGTON AND SCHOOL STREETS. M DCCC XLVIII. a 7. 184-8 Entered according to act of Congress, in the year 1847, by F. E. OLIVER, AND W. W. MORLAND. in the Clerk's Office of the District Court of the District of Massachusetls. bostos: printed by thurston, torhy and co. 31 Devonshiie Street. TO JAMES JACKSON, M. D. PROFESSOR EMERITUS OF THEORY AND PRACTICE OF PHYSIC IN HARVARD UNIVERSITY, HONORARY MEMBER OF THE ROYAL MEDICAL AND CHIRURGICAL SOCIETY, ETC. ETC., DISTINGUISHED ALIKE FOR HIS PRIVATE VIRTUES, PROFESSIONAL EMINENCE, AND HIS UNWEARIED AND INVALUABLE LABORS IN THE CAUSE OF MEDICAL SCIENCE, THIS TRANSLATION IS, BY PERMISSION, MOST RESPECTFULLY DEDICATED. a* TRANSLATORS' PREFACE. The classical work now first presented to the medical public in the form of a translation, can need no other recommendation to secure its cordial reception, than the name and reputation of its celebrated author. We may hazard an expression of surprise that it has so long remained unclothed with a garb, which would have introduced it more universally to the profession in this country. With precepts of inestimable value to the student, it combines a vast collection of details interesting to the practi- tioner. Whoever has followed the author in his clinical practice, and remarked his admirable qualities as a diagnostician of dis- ease, his unfailing detection of the most obscure symptoms, his accurate prognosis, and remarkable skill in exhibiting and ex- plaining cadaveric lesions, will readily discover, in the present work, the reflection of his practical labors. We trust that our task, by no means a light one, has been, at least, faithfully performed. The few additions, in the form of notes, relate chiefly to new discoveries in medical science, announced since the appearance of the last French edition, or to questions still undecided, and consequently open to remark. Boston, November 12, 1847. AUTHOR'S PREFACE. General Pathology treats of diseases considered abstractly, or in regard to that which is common to them all. It serves at once as introduction and sequel to special or descriptive pathol- ogy, whose end is the knowledge of each particular malady to which man is subject. It comprehends all that is most simple, and likewise what is most elevated in science; on the one hand, the definition of terms and the description of the phenomena of disease; on the other, the discussion of all those fundamental questions and the exposition of those general principles, which are to guide the physician in the arduous practice of a pro- fession closely connected with the dearest interests of humanity. General Pathology, consequently, comprises within itself the most unpretending elements and the most exalted philosophy of medicine. In this new edition we have not departed from the plan and rules which were adopted in those preceding it. We have treated of disease in general, as we should of any one malady in particular, when intending to give the most complete account of it possible. The definition of disease in general, and the mode of defining each one in particular ; the nomenclature, seat, causes, and precursory phenomena of diseases; their symptoms, progress, duration, and varied terminations; convalescence, consecutive phenomena, relapse, and recurrence; the distinction of genus, X author's preface. of species, and of pathological varieties; complications, diag- nosis, prognosis, anatomical changes, and treatment; the inti- mate nature of diseases, their classification, and the examination of the principal works upon general pathology, are each the subject of a special chapter. We resolved, in the first edition of this work, to abstain from any systematic idea, and to adhere strictly to the narration of facts, and the consequences rigorously deduced from them. We dare not flatter ourselves that we have completely accomplished this, but perhaps may be permitted to think that a near ap~ proach to it has been made. In fact, in the midst of the immense progress which medicine has made in its positive truths, and the great revolutions which it has undergone in its theories, we have not erased, in this new edition, anything essential of what the first contained, which was published in 1817, twenty-three years ago. If, however, but little of the former has been suppressed, we have been obliged to make, in this, the third edition, numerous and important additions. Within the lapse of twenty-three years, auscultation has been discovered; percussion, perfected in its manoeuvres, has been extended in its applications; the observation of pathological phenomena during life, and the study of anatomical lesions after death, have been brought to a degree of precision, which, previ- ously, they did not possess, and have furnished us with many new facts; chemistry and the microscope have lent their aid to pathology; most positive consequences have been deduced from the comparison and enumeration of better observed facts; diagnosis has become more exact, and experiment more rigor- ous. We have sought, in this new edition, to omit nothing of whatever important conquests have been made by science : this has been a long and difficult task, in the midst of the duties of medical teaching and the demands of practice. Thus, even with the assistance of two young and highly distinguished physicians, MM. Dalmas and Grisolle, who have kindly made, in the works recently published, the necessary researches for the AUTHOR'S PREFACE. xi present volume, six years have elapsed, from the time when the preceding edition was exhausted, to the publication of the present one. This new edition is far more extended than the second. The chapters devoted to the causes, the symptoms, and the progress of diseases, have been subjected to important modifications, and have received considerable additions. We have given to the chapter on Diagnosis a new form and very great development: the part relating to therapeutics has been greatly augmented; and we would particularly mention two articles, — one, devoted to the exposition of the rules of experiment in medicine; and the other, to the examination of a question sharply contested, — the application of the numerical method to pathological facts. Paris, October 21, 1840. CONTENTS. CHAPTER I. PATHOLOGY, ITS IMPORTANCE, EXTENT, AND DIVISIONS. --GENERAL PATHOL- OGY, ITS EXTENT AND LIMITS ; THE ADVANTAGES AND DANGERS ATTEND- ING ITS STUDY ; MODE OF ITS EXPLICATION ...".. 1 CHAPTER II. GENERAL AND SPECIAL DEFINITIONS OF DISEASE.....6 CHAPTER III. NOMENCLATURE OF DISEASES. — SYNONYMY. — ETYMOLOGY . . .13 CHAPTER IV. SEAT OF DISEASES ...... CHAPTER V. ETIOLOGY, OR THE CAUSES OF DISEASE ARTICLE I. Determining causes . . 21 Common determining causes 21 Circumfusa ... 22 Applicata .... 23 Excreta, gesta, percepta . 24 Specific determining causes 25 Common specific causes . 25 Metallic emanations . . 25 Miasmatic exhalations . 25 Poisons . ... 26 Contagious specific causes or virus 26 ARTICLE II. Predisposing causes . . 31 SECTION I. General predisposing causes . 32 Atmosphere . . .32 Winds.....32 Atmospheric pressure . . 33 Light.....33 Electricity . . . .33 Seasons.....33 b ......19 Planetary influences . . 34 Localities . . . .34 Garments . . . .36 Food.....36 Moral affections . . .36 Political institutions . . 36 SECTION II. dividual predisposing causes . 36 Aptitudes . 37 A. Origin . 37 B. Age . . 39 C. Climacteric years . 40 D. Sex . . 41 E. Temperament . 41 F. Constitution . 42 G. Habits . 42 H. Occupation . 43 I. Affluence and poverty . 43 J. Healthy, convalescent c r dis- eased condition . 43 K. Pregnancy . 44 Individual predisposing c auses proper . . 44 XIV CONTENTS. A. Circumfusa (dissect'g rooms, hospitals, change of climate) B. Applicata (clothing, various causes of compression, beds, baths)..... C. Ingesta (food, drinks, spices, condiments, medicaments) D. Excreta (evacuations) E. Gesta (exercise, repose, fa- tigue, want of exercise, watch- ing, sleep) .... F. Percepta (sensations, pas- sions, mental exertion, ante- cedent diseases) ARTICLE III. Occasional or exciting causes ARTICLE IV. Mode of action of the different mor- bific causes 44 45 48 50 51 52 53 55 Determining causes Aptitudes .... Predisposing causes proper Occasional causes ARTICLE V. Division of diseases relatively to their productive causes . Innate or congenital diseases . Acquired diseases Sporadic diseases Pandemic diseases Endemic diseases Epidemic diseases Essential diseases Symptomatic diseases ARTICLE VI. Lapse of time between the applica- tion of the causes and the de- velopment of diseases . 55 57 58 63 64 64 64 64 64 64 65 69 69 69 CHAPTER VI. PRECURSORY PHENOMENA, PRELUDES, ANTECEDENT SIGNS, PRODROMES, OR IMMINENCE OF DISEASES......• • .70 CHAPTER VII. SYMPTOMS OR SYMPTOMATOLOGY ........ ARTICLE I. Muscles, (paralysis, tremor, ri- Symptoms furnished by the func- tions of relation . . .75 gidity, subsultus, carphology, convulsions, contraction, etc.) SECTION I. Symptoms furnished by the exter- nal appearance A. Attitude .... B. Volume of the body . C. Growth of the body . D. Firmness of the flesh E. Color of the skin F. Eruptions .... G. Plicatures .... H. Tumors, excoriations, fis- sures, ulcers, fistula . Symptoms furnished by the head . Symptoms furnished by the neck . Symptoms furnished by the chest . Symptoms furnished by the shoul- ders ..... Symptoms furnished by the abdo- men ..... Symptoms furnished by the organs of generation Symptoms furnished by the limbs SECTION II. Symptoms furnished by the organs of locomotion Bones..... 75 75 76 77 78 78 80 80 80 81 90 91 91 92 94 95 97 97 SECTION III. 98 Symptoms furnished by the voice and speech .... 102 SECTION IV. Derangements of sensibility and of sensation considered as symp- toms ..... Internal sensations (pain) External sensations A. Sight Hearing B. C. D. E. Smell Taste Touch 104 105 108 108 109 109 109 109 SECTION V. Symptoms furnished by the affec- tive functions . . .110 SECTION VI. Symptoms furnished by the intel- lectual functions (delirium) .111 SECTION VII. Symptoms furnished by sleep (sleeplessness, dreams, som- nolency, coma, etc.) . .113 CONTENTS. XV SECTION VIII. Lipothymia, syncope, vertigo . 115 ARTICLE II. Symptoms furnished by the inter- nal or assimilative functions 116 SECTION I. Symptoms furnished by digestion 117 A. Hunger .... 117 B. Thirst . . . .118 C. Examination of the various parts of the mouth . .118 The teeth . . . .118 The gums . 119 The tongue . . .119 D. Mastication . . .123 E. Deglutition . . .123 F. Stomachal digestion . . 125 1. Nausea .... 125 2. Subsultus praecordiorum . 125 3. Regurgitation . . . 125 4. Vomiting .... 126 5. Pain . . . .127 Symptoms furnished by the intes- tinal canal . . . 128 1. Borborygmi . . . 128 2. Gurgling . . . .128 3. Passage of alimentary sub- stances .... 129 4. Alvine excretion or defeca- tion .....129 5. Excreted substances or ex- crements . . . '131 SECTION II. Symptoms furnished by the respi- ration . . . .134 1. Frequency . . . 134 2 Quickness . . . 135 3. Quantity of air inspired and expired . . . .135 4. Difficulty of respiration . 135 5. Inequalities of respiration 136 6. Concomitant sounds . . 136 7. Qualities of the expired air 137 8. Auscultation . . . 137 Modifications of the respira- tory murmur . . 140 Rales . . . .140 Metallic tinkling . . 145 Thoracic succussion . . 146 Pleuritic friction sound . 147 Auscultation of the voice . 148 Bronchophony . . . 148 .^Egophony . . . 149 Pectoriloquy . . . 150 Percussion of the chest . 151 §11. Respiratory phenomena . 152 1. Laughter .... 152 2. Yawning . . . .152 3. Sneezing .... 152 4. Hiccough . . 152 5. Cough . 152 Exspuition . 154 Expectoration . . 154 Sputa . 155 SECTION III. Symptoms derived from the circu- lation .....162 & I. Circulation of the blood . 163 A. The heart . . . .163 1. Extent of the heart's pul- sations .... 164 2. Shock or impulse . . 165 3. Nature and intensity of the sound .... 166 4. Rhythm . . . .169 B. The Pulse . . . .170 Auscultation of the arteries 179 C. Symptoms furnished by the capillary circulation . . 180 D. Symptoms furnished by the venous circulation . . 181 E. Symptoms furnished by the examination of the blood . 182 § II. Symptoms furnished by the lymphatic system . . 189 SECTION IV. Symptoms furnished by the heat . 192 SECTION V. Symptoms furnished by the ex- halations and secretions . 195 § I. Exhalations . . . .196 A. Natural exhalations . . 196 1. Cutaneous exhalation, or perspiration . . . 196 2. Mucous exhalation . .198 3. Serous exhalation . . 199 4. Exhalations upon the artic- ular surfaces . . . 199 5. Exhalations within the eye, the ear, the adipose cells, the lymphatic and sanguine- ous system, etc. . . 200 7. Gaseous exhalation . . 200 8. Sanguineous exhalation . 200 B. Morbid exhalations . . 200 1. Haemorrhage . . . 200 2. Pyogenia . . . .201 Pus considered in regard to its chemical properties and its action upon the animal economy . . 204 C. Artificial exhalations . . 206 § II. Secretions, properly so called 206 1. Secretion of tears and the fluid of the meibomian folli- cles .....207 2. Secretion of the saliva . 207 3. Secretion of the bile . 208 XVI CONTENTS. 4. Secretion of the pancreatic juice . 210 5. Secretion of the urine . 210 Physical and chemical prop- erties of the urine . 212 § III. Excretions . . .219 SECTION VI. Symptoms furnished by absorption 220 SECTION VII. Symptoms furnished by nutrition . 222 Augmentation (hypertrophy) 222 Diminution (atrophy) . . 222 ARTICLE III. Symptoms furnished by the gen- erative functions . . . 223 A. In the male . . . 224 B. In the female . . .224 ARTICLE IV. Symptoms considered in disease . 226 Local and general symptoms . 227 Sympathetic phenomena ; sym- pathies .... 227 Principal and accessory symp- toms ... . . .228 Active and passive symptoms . 229 Epiphenomena . . . 229 CHAPTER VIII. THE PROGRESS OR COURSE OF DISEASES Types.....231 Acute and chronic course . 233 Periods in diseases . . . 233 Invasion.....234 Period of stasis or violence . 235 Period of decline . . . 235 . 230 Circumstances which modify the course of diseases (ages, tem- perament diurnal revolutions, temperature, planetary influ- ences, climate, etc.) 236 DURATION OF DISEASES CHAPTER IX. . 240 CHAPTER X. TERMINATION OF DISEASES ARTICLE I. Different modes of termination . 242 In the return to health . . 242 In death.....244 In another disease . . . 245 Doctrine of crises . . . 246 Seat of critical phenomena . 247 Precursory signs of critical phe- nomena .... 249 ......242 Circumstances which favor or oppose critical phenomena . 252 Duration of critical phenomena 252 Influence of critical phenomena upon the termination of dis- eases .....253 ARTICLE II. Doctrine of critical days 256 CHAPTER XI. CONVALESCENCE 259 CHAPTER XII. CONSECUTIVE PHENOMENA 262 CONTENTS. XV11 CHAPTER XITI. RELAPSE AND RECURRENCE.........264 CHAPTER XIV. THE DIFFERENT GENERA, SPECIES AND VARIETIES OF DISEASES . . . 266 CHAPTER XV. COMPLICATIONS...........270 CHAPTER XVI. DIAGNOSIS............273 I. Diagnostic signs . . . 273 II. Necessary conditions on the part of the patient and the physician in forming a diag- nosis .....275 Different modes of exploration for forming diagnosis . 276 1. Pressure .... 276 2. Palpation . . . 278 3. Touch . . . .280 4. Succussion . . . 282 5. Mensuration . . . 283 6. Percussion . - . 286 7. Auscultation . . . 290 8. Exploration by sounds and probes .... 293 9. Exploration by specula . 294 10. Examinations with the mi- croscope and the magnify- ing glass .... 297 11. Employment of chemical agents in the diagnosis of disease .... 297 § III. Mode of examination and interrogation of patients for the purpose of forming a diag- nosis ..... 298 Order to be observed in ques- tioning patients . . . 301 Examination of the existing symptoms .... 302 Exploration of the head . . 303 Exploration of the spine . . 303 Exploration of the auditory canal 304 Exploration of the nasal fossae . 304 Exploration of the isthmus of the fauces, the larynx and the oesophagus .... 305 Exploration of the chest . . 306 Exploration of the abdomen . 308 Exploration of the genital organs 309 Exploration of the rectum . 310 Exploration of the limbs . . 310 $ IV. Principal component ele- ments of diagnosis . .311 A. Determination of the seat of diseases . . . .312 1. Which is the affected organ? 312 2. The seat of disease being known, what is its extent? 314 3. Which of the elementary tissues is primarily affected? 315 B. Determination of the lesion 316 1. Nature of the lesion . . 317 2. Degree attained by the le- sion .....318 C. Symptomatic phenomena con- sidered in regard to diag- nosis . . . .319 § V. Circumstances which may render diagnosis difficult and even uncertain . . .321 1. Difficult diagnosis on ac- count of the period at which the physician is summoned 321 2. Difficulties in diagnosis de- pending upon the predomi- nance of general phenom- ena, or the obscurity or absence of local phenomena 323 The febrile state in relation to diagnosis . . . 330 3. Difficulties in diagnosis re- sulting from the infrequency of the disease . . . 336 4. Difficulties resulting from complications . . . 337 5. Difficulties resulting from deception . . . 338 Feigned and concealed dis- eases .... 338 XV111 CONTENTS. CHAPTER XVII. PROGNOSIS ..... § I. Conditions on the part of the patient and the physician for the formation of the prognosis . 341 § II. Prognostic signs . . 342 1. Diagnosis the original basis of prognosis . . . 343 2. Power of nature and of art 344 3. Age, previous health, phys- ical and moral causes . 344 Hereditary condition . 345 Menstruation, pregnancy, the puerperal state . 345 Habitual intemperance . 345 Excessive evacuations — fa- tigue . . . .346 Climate — seasons . . 346 4. Precursory phenomena . 346 347 347 ......341 5. Commencement of diseases 346 6. Progress of diseases . . 347 7. Duration of diseases . 347 8. Influence of remedies pre- viously employed . 9. Complications . Prognostic value of certain symptoms considered sep- arately (external appear- ance, aphonia, pain, sen- sorial disturbance, deli- rium, sleep, dysphagia, hunger, thirst, meteor- ism, involuntary evacua- tions, stertorous respira- tion, syncope, sweats, haemorrhage, parotiditis) 348 CHAPTER XVIII. THE DIFFERENT ALTERATIONS PRESENTED BY THE ORGANS AFTER DEATH . 357 . 370 . 371 . 372 . 372 . 372 . 372 . 373 . 373 . 373 . 373 . 373 . 373 . 373 ARTICLE I. Mode of conducting post-mortem examinations . . . 358 Examination of the exterior of the body .... 358 Inspection of the internal organs 359 Mode of opening the great splanchnic cavities . . 360 Order in which visceral inspec- tion should be conducted . 361 ARTICLE II. The principal lesions presented by the organs after death . .365 FIRST SERIES. Lesions of the solids . Inflammation of the various tis- sues Ulcers Scirrhus .... Melanosis Cutaneous transformation Mucous transformation Serous transformation Fatty transformation Fibrous transformation Oseous transformation Cartilaginous transformation Corneous transformation . Alterations of form . Alterations of volume Alterations of color . Fistula . Gangrene Tubercle Granulations Cancer 365 366 367 368 368 368 369 370 SECOND SERIES. Alterations of the fluids . . 374 Alterations of the liquids . . 374 Alterations of the gases . . 377 THIRD SERIES. Foreign bodies, inanimate and liv- ing •.....378 Different importance of cadaveric changes.....379 CHAPTER XIX. THERAPEUTICS Observation and experience the only guides in the study of therapeutics . . . 381 Experimentation, its difficulties, the requisite rules in its pur- suit .....383 ......380 The numerical method applied to the study of diseases . 393 Refutation of the principal ob- jections to the numerical sys- _tem......395 Experience in medicine . . 403 CONTENTS. XIX Physical and chemical theories applied to therapeutics . . 405 ARTICLE I. Indications . Conditions productive of indica- tions . A. Genus of the disease B. Character of the disease . C. Type of the disease . D. State of the vital forces E. Intensity of the disease F. Different periods of the dis- ease ..... G. Particular symptoms H. Seat of diseases I. Complications . J. Causes .... Temperament, constitution, age, sex, profession, hab- itual regimen . K. Commemorative circumstan- ces ..... 406 406 406 407 407 408 412 412 413 414 414 414 415 416 L. Means previously employed 418 M. Epidemic constitution . 419 N. Tendency of the disease . 419 O. Influence exercised by the disease upon the constitu- tion .....420 Possibility of the occurrence of several indications in one and the same disease . 420 Preservative indications . 422 Principal indications in con- valescence . . . 423 Indications furnished by the consecutive phenomena . 423 ARTICLE II. Therapeutical means . . . 423 Therapeutical means, properly so termed . . . 424 Surgical means . . . 424 Medical means . . . 425 General or hygienic means . 428 Means in acute diseases . 429 Means in chronic diseases . 434 CHAPTER XX. NATURE OR ESSENCE OF DISEASES........435 Ideas of the humoral pathologists........437 Ideas of the Solidists..........438 CHAPTER XXI. CLASSIFICATION OF DISEASES 442 CHAPTER XXII. PRINCIPAL WORKS UPON GENERAL PATHOLOGY 444 ERRATA. Page 80, lines 19 and 23, for " vesicula," read vesicula. " 101, line 16, insert a comma after "attacks." " 115, lines 11 and 32, for " Topor," read Sopor. " 117, line 21, for "boulimus," read boulimia. " 117, lines 24 and 26, dele the parentheses. " 128, line 25, for " sound," read sounds. " 136, note, for ntvm, read nvtm. " 182, line 35, for " Nosographic," read Nosographie. " 186, line 13 from bottom, for "secretions," read secretion. " 189, line 20, for " Seltzar," read Seltzer. " 189, line 4 from bottom, for § I. read § II. " 197, line 30, for " mouldiness," read mould. " 200, line 5 from bottom, for " haemorrhages consist," read hemorrhage consists. " 208, line 7 from bottom, for " after," read of the. " 213, line 30, for " a thousandth," read of a thousandth. " 226, line 14, for " venerens," read venereus. " 229, last line, for " epigenometa," read epigenemeta. " 231, note, for yvQe£og, read nvqs^ig. " 300, line 3 from bottom, for " diagnosing," read diagnosticatmg. ELEMENTS OF GENERAL PATHOLOGY. CHAPTER I. PATHOLOGY, ITS IMPORTANCE, ITS EXTENT, AND ITS DIVISIONS. — GENERAL PATHOLOGY, ITS EXTENT, ITS LIMITS.--ADVANTAGES AND DANGERS ARISING FROM ITS STUDY.--ORDER ADOPTED IN ITS EXPO- SITION. Pathology has been defined to be that branch of medicine which treats of the classification, causes, symptoms and signs of disease. This definition is far from accurate. As it is the pecu- liar province of physiology to treat of whatever relates to the human body in its normal condition, so pathology includes within its limits whatever relates to the same in a state of disease. The seat of diseases, the phenomena which precede and follow them, their progress, duration and different modes of termination, their reappearance, various forms and complications, the changes they produce in the texture of organs, their prophylactic and curative treatment, &c. &c., are but so many essential points in their his- tory, which necessarily fall within the cognizance of pathology,* or that branch of medical science, the object of which is the know- ledge of disease. Of the various branches of the healing art, none to the physician is so attractive as a study, none so important in its results, as pathology. He views it as a centre, around which are disposed at unequal distances the other natural sciences. The study of anat- omy and physiology, of chemistry and physics, of botany and * lla6og, disease; loyog, discourse. 1 2 GENERAL PATHOLOGY. materia medic a, afford him but an introduction to that of pathol- ogy ; he regarding those sciences of far less importance, so soon as the latter shall become the object of his special study, viewing them rather as accessory sciences, and among the numerous facts presented by them, noting only those which are nearly connected with the knowledge of disease, and its appropriate methods of treatment. We would not however exalt the science of pathology at the expense of the other branches of natural history; whatever be its importance, and the dignity of its aim, we claim for it no supe- riority over the other sciences. Physiology, physics, zoology, &c, it will not be denied, are entitled to equal consideration. Inti- mately connected as are all these sciences, they reciprocally aid in the elucidation of each other, and none among them should be allowed the preeminence, although in his estimation who makes it his particular study, either will appear of paramount importance. Pathology, like the other natural sciences, is without limit; while botany, zoology, physics, chemistry and mineralogy are daily ex- tending their domain, the science of disease, also, to the observer, appears to be rapidly advancing. Without here referring to the ever new and infinite varieties of disease, this must be evident, whether we consider the more careful study of causes, the more accurate description of symptoms, the more critical examination of the circumstances which exert a favorable or unfavorable in- fluence upon the progress of diseases, the discovery of affections previously unknown or imperfectly described, or lastly, the appli- cation of new methods of exploration to the phenomena of disease. To cite a recent example, has not the discovery of auscultation, in our own time, added to the history of thoracic disease, a multitude of phenomena and valuable diagnostic signs, of which we were previously ignorant ? Pathology presents for consideration, a mass of facts, all the details of which it is beyond the power of the human mind to comprehend; it may even be asserted that, throw- ing aside its theories and its systems, no one is possessed of all the knowledge contained in the records of pathological science. This want of correspondence between the extent of the science and the capacity of the human mind, has led to results which were not unforeseen. It being impossible to increase the mental powers, it was attempted to make a division of the science into several parts which should be within the reach of our intellectual capacity. Hence the numerous divisions of pathology. Of these the most important is that distinctive of internal or medical, and external or surgical pathology. The diseases of women, of children, of the aged, those seated, whether in any of the splanchnic cavities, in any of the great anatomical systems, in an apparatus, or single organ, &c., have severally undergone subdivision; and eminent professional men have deigned to devote themselves exclusively to the study of a single class of these affections. But it should be recollected that, in no instance, has the investigation of a special group of diseases been of profit to the science, except so far as GENERAL PATHOLOGY. 3 those, who have devoted themselves to these studies, have been well versed in the other branches of pathology. Diseases are not confined in their effects to single organs, nor can they be discon- nectedly studied. There is another division, which has had the effect to enlarge rather than diminish the range of the science, and which, like that adopted by Bichat in the study of anatomy, has extended its lim- its. We refer to the division into general and descriptive patholo- gy. The object of this is not to divide the science into several parts, nor to separate a particular class of diseases from all others. General pathology, whose object it is to treat of diseases in the abstract, and of whatever is common to them, includes all under the same head, studies their general characteristics, causes and development, the succession and connection of their phenomena observed during life, the appearances after death, and the circum- stances which modify their progress, and by which we are enabled to prognosticate the changes which will take place in their course. Descriptive pathology includes alike all diseases, but presents them in a series of groups, in which each affection is described, with the appearances peculiar to it, and which serve to distinguish it from all others. Hence, it is evident that there is no analogy between this division of the subject, and those before mentioned. The latter shorten the study, by presenting fewer objects for in- vestigation ■; the former leads to the same result without narrowing the limits of the science; and not only does it preserve it entire, but by presenting, under different aspects, the objects to which the attention should be successively directed, we obtain a more accu- rate knowledge and a more just appreciation of them. This division differs also from the first in other respects. It is possible to devote ourselves exclusively to the study of internal, and neglect to a certain extent that of external pathology: so special study may be made of those diseases which occur during child- hood or old age, while those peculiar to other periods of life are neglected. General and special pathology, on the contrary, cannot be exclusively studied; one is but an introduction to the other; both are indispensable to the physician. This division of pathology is one, the limits of which are the most clearly defined. The consideration of all the phenomena common to diseases belongs to general pathology, while whatever relates to the history of particular diseases falls within the prov- ince of descriptive pathology. Between these two branches of pathology, there are however numerous points of contact; but it is not a little singular that most authors who have treated upon general pathology, should have introduced, among considerations legitimately within the province of that subject, the history of particular diseases. Thus the description of plethora is found in almost all treatises upon general pathology. Sprengel, in his valuable work * upon this subject, goes still farther, and treats * Pathologia Generalis. Amstelodami, 1813. 4 GENERAL PATHOLOGY. successively (in the article, Etiology,') of the signs of the various fractures, dislocations, and hernise, and describes the various kinds of worms which infest the human body, with the signs indicative of their presence. While subjects are thus considered in connec- tion with general pathology, which are not within its scope, others strictly belonging to it are neglected. The nomenclature of dis- eases, the circumstances which influence their course, the treat- ment, convalescence, and appearances after death, the mode of examination and interrogation of patients, are all important points in the general history of diseases, which authors have hitherto omitted to mention, although as essential to it as the classification, causes, symptoms and signs. If the division of pathology into general and descriptive, appear to some rather to prolong than to abridge the study of diseases, it will be an easy task to bring them to a more just conclusion. We readily grant that the knowledge of particular diseases is of the highest importance, and that the study of general pathology is not of equal utility to the practical physician. But admitting for a moment, that the latter be wholly valueless to him who is already versed in science, it would not be therefore just to conclude that it is without profit to the student. Without here referring to the ab- solute necessity of his first becoming familiar with a new language, the study of general pathology is to him in other respects of man- ifest utility; all is as yet new to him, he should leave no point unattained. Diseases possess certain forms in common, they have also features which are peculiar to them. Were it not better, we would then ask, to present to the beginner, once for all, the vari- ous points of doctrine, and the phenomena common to most dis- eases, and thereby avoid the necessity of afterward pointing out those peculiar to each, than to weary him with tedious and unpro- fitable repetitions, which, in the description of each particular dis- ease, must necessarily lead to an incomplete examination of the same questions ? In short, should he be made acquainted at once with the characteristics common to all diseases, or be under the necessity of reviewing the same, as often as he should be led to the investigation of a particular disease ? The answer is evident. There are still numerous other advantages attending the study of general pathology. It gives scope to considerations, favorable to the development of the understanding, and an enlargement of the views of the student. It briefly points out to him, at the com- mencement of his career, the path he should pursue, the objects which claim his attention, and the dangers to be avoided; it also indicates the course which should be adopted in the investigation of particular diseases; and lastly, by grouping together these va- rious affections, it aids in the elucidation of their history. But aside from the advantages, there are dangers connected with the study of general pathology. A cursory examination of the treatises upon this subject will alone suffice, to show us the systems and hypotheses, which have been either substituted for, or mingled with, the results of observation or experience. The same GENERAL PATHOLOGY. 5 may be said, it is true, of most medical treatises, whatever be their object, as descriptions of particular diseases, and even records of observations. But systems properly so called, those great hypotheses, by which the universality of facts is understood and explained, necessarily proceed from general pathology. The com- parison of diseases, the study and comparison of their various phenomena, necessarily lead to those general conclusions so seductive to the mind, which receives them with dangerous facility, proudly proclaiming them as secrets wrested from nature, as laws without exception ; and should they afterward be shown by facts to be inaccurate or false, to nature rather than to the theory is the error ascribed; the freaks and caprices of nature excite astonishment, while the theory is still regarded with admi- ration, until some other takes its place, which ultimately shares the same fate. When it is considered that general pathology treats of subjects abstractly, and that hence it becomes easy to wander from the truth, the tendency of this science to the formation of those theories by which the progress of medicine has been so long impeded, becomes manifest. If the knowledge of the dangers be sufficient in order to avoid them, we hope that we ourselves have escaped from those to which we have just alluded; but whatever may have been our efforts to attain this end, we dare not flatter ourselves that we have succeeded. Those most averse to theories and hypotheses, have not in all cases been able to guard against them ; they have over- thrown the hypotheses of others, by substituting those of their own invention, and which appeared to them but the legitimate results of observation and experience. It was a remark of Gai/bhis, that it is better to pause, than go blindly forward; and yet, in the same work, he himself becomes enveloped in the mists of humorism, and gravely descants upon the chemical and mechani- cal acrimonies of the humors. If, as we have seen, the province of general pathology has not been with certainty determined, and it be necessary to strip it of the erroneous and dangerous theories which have till now rendered it obscure, it is no less important that a far different course be adopted in its exposition, from that hitherto pursued. By refer- ring, as has been the case, to nosology or the classification of dis- eases, their definition, seat, course, duration and complications, subjects are considered under the same head, which should be separately studied, and which are as widely different as signs and symptoms, from which two distinct branches have arisen; if, in connection with the nosology, the seat, progress and duration of diseases, which have but a vague affinity to their classifications, be considered, it is not clear why on this, all other branches of general pathology should not depend. Is the method to be pursued in the study of general pathology an important consideration ? Is it absolutely necessary, for exam- ple, in our inquiries, that prognosis be considered before diagnosis, or the causes before the seat of disease 1 We think not; but are 1* 6 DEFINITION OF DISEASE. yet of the opinion that there are certain points in the history of diseases, which, before others, naturally claim our first attention. The definition of disease, is the first subject which presents itself; the study of the progress of diseases should not precede the exposition of the symptoms, and the causes more properly come before than after the latter; the diagnostic and prognostic signs should follow the symptoms, and the consideration of the treat- ment come after the signs. Thus among the various subjects em- braced by general pathology, there are those whose relative posi- tion is to a certain extent defined, while there are others which may be considered with equal propriety at different periods during the investigation. In the arrangement of the subjects which constitute general pathology, it seems to us important that some method be adopted, which shall be equally applicable to the study of particular dis- eases. This method would thus become more strongly impressed upon the mind. It is moreover well known that a uniform method powerfully assists the memory, accustoming the mind to a proper arrangement of its ideas, and the classification of the new truths which are daily presented. The following is the order we have adopted in the exposition of general pathology. We shall first consider the definition of disease in general, and point out the rules which should guide us in the definition of dis- eases respectively. After some considerations on the nomenclature, etymology and synonorrvy, we shall speak of the seat of diseases, their causes, precursory phenomena, symptoms, progress, dura- tion and various terminations. We shall thus be led to the ex- amination of the doctrine of crises and critical days. Convales- cence, the consecutive phenomena, relapse, kinds, varieties and com- plications of diseases, diagnosis and prognosis, will be generally considered. We shall also devote a chapter to the examination and appearances of bodies after death; and having touched upon the fundamental rules of treatment, we shall conclude by offering a few remarks on the nature and classification of diseases. — O. CHAPTER II. DEFINITION OF DISEASE IN GENERAL, AND OF DISEASES RESPECTIVELY. There are two kinds of definition, one being an accurate state- ment of the nature of a thing, the other a rapid enumeration of its principal characteristics. In either case, the definition to be correct, should present so clear an idea of the object defined, as to render it always recognizable, and easily distinguishable from all others. DEFINITION OF DISEASE. 7 Of these two kinds of definition, the first, which acquaints us with the nature of things, would be preferable to the second, were it as certain and general in its application; but there is a vast number of objects whose nature is unknown to us ; and though there be those in which it seems to be understood, this knowledge is rarely so well established, as to serve as a basis whereon to found a correct definition. The second mode of definition con- , sists rather in a brief description, than a definition of the object. It rests on phenomena appreciable to our senses, without reference to the nature of the object itself, which is beyond their reach, and the knowledge of which can only be attained by abstract reason- ing. It has been justly remarked by M. Dumas that abstractions mislead the mind, while truth is conveyed to us through the medi- um of our senses. The history of all sciences, and particularly that of medicine, proves the truth of this assertion. During the period when the first mode of definition was employed, the pro- gress of science was retrograde; when, on the contrary, the description came to be substituted for the definition, its advance was constant. I. Disease, as is well known, is that state opposed to health, a word the significance of which is familiar to every one. But to render an accurate definition is still no less difficult, as is evident from the number and variety of those which have been already proposed. Many physicians have attempted its definition by referring to its nature, or its ultimate cause. Alcmceon de Crotone made it to consist in a derangement of the forces, the concurrence and harmonious action of which result in health; Plato, in his definition, for forces, substituted elements, and Ascleplades replaced the elements of Plato by indivisible corpuscules; Sylvius viewed disease as a reaction of salts; Brown, a lesion of excitability; Hitter, a galvanic change; Baumes, a change in the proportion of caloric, oxygen, hydrogen, nitrogen and phosphorus; and Broussais, an effect of irritation, &c. Most of the other definitions of dis- ease, founded upon its nature, are either comprised in those above cited, or are so obscure, as to require a long explanation to render them intelligible; they have consequently been omitted in a work strictly elementary, and in which such a display of erudition would be out of place. Before taking leave of this subject, how- ever, due consideration should be given to the definition of disease proposed by Sydenham. This writer, with all his natural sagacity and soundness of judgment, attempted to define disease, according to its peculiar nature. " Dlctat ratio, si quid ego hie judico"* modestly says this eminent physician, umorbum quantum libet ejus causa humano corporl adversantur, nihil esse aliud quam naturm conamen materice morbificce exterminationem, in ccgri salutem, omni ope mollentisP This definition, although approximating in some respects to the present language of the science, is nearly as defec- * Sydenham, de morbis acutis in genere, page 19. 8 DEFINITION OF DISEASE. tive as those which preceded it, presenting but a vague idea of an indeterminate effort of nature, a power of which we are totally ignorant. Besides, the effort exerted by nature to destroy the morbific cause, would rather constitute the remedy, than the dis- ease. Finally, this reaction against the morbific cause does not always exist, and consequently Sydenham's definition, were it correct in other respects, would fail in this, since a definition should apply to all cases. The nature of disease being unknown, it becomes necessary to seek other grounds upon which to found its definition. This necessity has been recognized by pathologists of every age. Disease has by some authors been defined to be a derangement of the functions. To this it has been objected that mere function- al disturbance is insufficient to constitute disease, and that there are certain phenomena, which are capable of giving rise to the former, without producing the latter. A state of general disturb- ance ordinarily accompanies the catamenial flow in females, not however, amounting to disease. Parturition is attended with violent pains, is followed by a flow of blood, together with a feeling of weariness and debility, yet without the existence of disease. A violent passion, as anger or fright, may give rise to extreme functional disturbance, without however inducing disease. In old age, the exercise of the functions no longer takes place with the same regularity; the organs of generation become gradually unfitted for reproduction, the functions of relation become by de- grees enfeebled, the intellectual faculties become clouded, the sen- sations blunted, and the step unsteady. The organs of individual life themselves become subsequently affected, yet without the existence of disease. In the person who has been deprived in any way of an eye or an arm, there is not a regular exercise of all the functions, yet it is manifest that disease does not exist. A sensation of uneasiness in any part, an acute but momentary pain, a transient spasm, or involuntary movement, are instances of functional derangement, but cannot be considered as diseases. Disturbance of the functions alone is then insufficient to constitute disease, since even a considerable irregularity in their performance is not necessarily incompatible with health. To define health therefore to be that state in which all the functions are performed with harmony and regularity, is incorrect. There is, as has been said, an individual health which is influenced by a variety of cir- cumstances. This has been remarked by many physicians and has led them to modify the definition under consideration. Some have said, that functional derangement to constitute disease must be the result of morbific causes.* By others, the epithet preter- natural has been prefixed to signify that such functional disturbance must be a deviation from the ordinary course of nature.f This defi- * Ludwig, Patholog. Instit., page 6. f The Latin adjective frceternaturalis has commonly been construed by the word unnatural; this is far from its true sense : it expresses a deviation from not an opposition to, the ordinary course of nature. DEFINITION OF DISEASE. 9 nition thus modified, is more accurate, but is still susceptible of improvement. Every species of functional derangement, in which there is a greater or less deviation from the usual order of nature, constitutes a disease; but disease may exist independent of func- tional disorder. Hernia, for example, is a disease, but not always accompanied by disturbance of the functions. Tubercular degen- eration, a very serious disease, may occur in several glands, and even in a portion of an important viscus, as the lungs, without giving rise to apparent disturbance of the health. It has been maintained by some authors, that an anatomical lesion, which is not followed by apparent functional disorder should not be considered as a disease; that the disease can only be said to exist from the moment when certain phenomena of reaction render it evident. Disease, according to them, and M. Littre adopts this definition,f is "a vital reaction, either local or general, immediate or mediate, against some obstruction, disorder or lesion." According to this definition, a change of structure, however considerable, in those cases of aneurism at the root of the aorta, which some- times become far advanced without causing apparent disturbance of the health, would not become a disease till complete perforation of the vessel should take place; while the same lesion, occurring in another part of the same vessel, and causing either compression upon a neighboring organ, or giving rise to perceptible pulsations through the thoracic walls, would constitute a disease almost from its commencement. In a fracture, the disease would consist rather in the reaction against the lesion, that is, in the pain, difficulty of movement, and inflammation which is developed at the surface of the fragments and in the contiguous parts, than in the ana- tomical lesion itself. These two examples taken from the most familiar diseases, show the incorrectness of this definition, which has been before pointed out, in considering that proposed by Syden- ham, within which it is comprised. It follows from these considerations, that it is impossible to render a satisfactory definition of disease, without including changes of structure, whether accompanied or not by functional disturbance. Structural changes being in most diseases the principal, and functional disorders occurring, as secondary phenomena, it has been thought by some physicians that all diseases are necessarily connected with a material organic lesion, and that disease, con- sidered abstractly, should be defined an alteration occurring in the structure of the body. It should be recollected that in a great number of diseases, the existence of such an alteration is manifest, and is of the highest value in the appreciation, as well as in the definition of disease. It may be also remarked, that the number of affections, in which these changes are found to exist, is becoming more considerable in proportion to the advance of medical science, and will ultimate- f Dictionnaire de Medecine, ou Repertoire general, vol. xviii., article, Maladie. 10 DEFINITION OF DISEASE. ly become indefinitely increased; in addition to the discoveries daily made by pathological anatomists of lesion in the solid parts, previously unnoticed, chemistry is leading to similar results, by bringing to light important alterations in the fluids which enter into the composition of the human body, as the bile, blood, urine, &c. The changes observed in the quantity and consistence of certain fluids, and particularly the blood (plethora, anemia); the excessive accumulation of gas, in parts which naturally contain it, its formation in parts to which it is foreign, have added to the list of diseases, in which a material alteration exists. These lesions of the liquid and gaseous fluids, which form a part of the human body, deserve to be placed with those of the solid parts; and should, in the absence of lesions occurring in the latter, be comprehended, at least by inference in the definition of the disease. By thus observing the progress of the science, it may be very naturally inferred that, in proportion as our means of chemical analysis and observation become more perfect, those diseases in which hitherto no material lesion has been discoverable, will be gradually added to those whose primitive lesion is already known, and disease may then be defined to be an alteration occurring in the structure of organs. But in medicine, more perhaps than in any other science, we must be guided by facts; and as it often happens that this alteration escapes all our means of investigation, and the functional disturbance is alone appreciable, and conse- quently that alone which, in the present state of our knowledge, indicates and constitutes the disease, it becomes necessary, in at- tempting its definition, to characterize it by reference both to mate- rial lesions and to functional derangement. In the former editions of this work, we defined disease to be a perceptible change in the position or structure of parts, or in the exercise of one or many functions, relatively to the habitual health of the individual. We have thought proper, for the sake of brevity, to strike out the clause relating to the changes of position of organs, since such a change cannot be effected, unless there be also structural altera- tion of the parts: a hernia can only follow a structural change in the parietes of the splanchnic cavities; dislocation can only take place after rupture, or some other alteration in the parts, of which the articulation is composed. We would likewise omit the last clause of the definition, relatively to the habitual health of the in- dividual, as good sense alone indicates this condition, which more- over would be more appropriately placed among the considera- tions which precede the definition, where it is presented with its necessary developments. We have also employed another expres- sion in place of the word structure, which does not so well apply, in common phraseology, to the changes which occur in the com- position and quantity of the fluids, or to alterations in the volume of the solid parts, when at the same time unaccompanied by manifest alteration of the tissues. It being impossible to define DEFINITION OF DISEASE. 11 disease according to its nature, and to obtain a clear idea of it except from what is revealed to us by its phenomena, we give the following definition: a perceptible disorder occurring, either in the material disposition of the parts composing the living body, or in the exercise of its functions.* Some authors have endeavored to create a distinction between affection and disease, expressions generally employed as synony- mous. It has been thought by some that the word affection is more appropriately applied to surgical cases, while those strictly medical, would be better indicated by the word disease. Others have maintained that disease consists in structural lesion, and af- fection in the sensible phenomena arising from such lesion. Sprengel, who presents this distinction, thinks it should serve as a base for the division of pathology into general and special; the former treating of diseases, the latter of affections. In the sense in which Sprengel employs these two expressions, both belong equally to general, and descriptive or special pathology. This distinction between affection and disease ought then to be rejected, as con- trary to common acceptation, and as rendering the language obscure without elucidating the subject. The words affection and disease therefore, in medical phraseology, are used synonymously, although the latter, considered in its most general sense, admits of a different signification. II. Having defined disease in general according to the principles previously established, we shall proceed to consider the mode of defining diseases respectively. These considerations belong to general pathology, inasmuch as they apply to all diseases. To obtain a correct definition of each particular disease is of far more importance, than the attainment of a clear idea of disease in general. Being ignorant of the nature of diseases respectively, as well as of disease in general, it is necessary that we define them also ac- cording to their sensible phenomena. It has been recently advanced, that a disease can only be defined by determining which is the organ affected and the character of that affection; but this kind of definition which can only apply to a limited number of diseases, is not strictly a definition. To say that pleurisy is an inflammation of the pleura; tabes mesenterica, a tubercular degeneration of the mesenteric glands ; ascites, an ef- fusion of serum into the peritoneum; epistaxis, a haemorrhage from the pituitary membrane; is to give a signification of the word, and not a definition of the disease. Another and more serious inconve- nience connected with this kind of definition, is the uncertainty in respect to the seat of certain diseases, and the conflicting opinions among physicians on this point. How various, for example, * This definition appears to us more accurate than any other, although defec- tive in some respects ; this imperfection is, perhaps, inherent in the subject un- der consideration. Health and disease are often confounded. How is it possible to define with strict accuracy things not always distinct ? 12 DEFINITION OF DISEASE. would have been the definitions of intermittent fever, whose seat has been placed in the liver, spleen, stomach, intestines, nervous system, skin, vena porta, lymphatic vessels of the mesentery, and to what confusion would these contradictory statements have given rise! It is necessary then, in order that the definition be always intelligible, to define these affections according to their phenomena. There are also cases, in which the manifest cause of diseases be- comes an accessory element in their definition: contusions, wounds, lead colic, asphyxia, syphilis, variola, &c, cannot be accurately de- fined, unless the cause which produced them be indicated. In general, in order to the correct definition of a disease, it is necessary to collect the greatest possible number of detailed cases, relating to it; to compare them with each other, so as to isolate those phenomena which are constant, from those which are simply accidental. The phenomena which are found to occur in all the cases, or at least in the majority, form the characteristic features of the dis- ease ; their brief enumeration will present an outline of the latter, constituting its definition. Some diseases appear with such different degrees of intensity, that it would be impossible to include in a common description these various forms of the same affection: cerebral haemorrhage, for example, gives rise to phenomena so various, according to the size of the coagulum, that it is indispensable, in order to give a cor- rect idea of this disease, to present a descriptive definition of its principal forms, as in natural history, in which the representation of a plant or animal is given, in its principal phases of existence, and in its various proportions. The remark of Grimaud, that the thorough knowledge of a disease is only to be obtained, by study- ing it at the age, and in the sex, temperament and climate, which observation has shown to be congenial with it, is incorrect; "for," says he, " every disease,* like every natural being, appears in its true light, and enjoys the whole plenitude of its existence, only when formed and developed under a concurrence of circumstances, which are analogous to it, and equally tend to favor its production." The physician, whose knowledge of a disease only extends to its se- verest form, can have but an imperfect idea of it, being acquainted only with its exceptional form. It should be studied, on the contrary, in all its varieties, and if there be any which deserve particular attention, it should first be those of most frequent oc- currence, and afterwards those whose characteristics are least ap- parent, the former on account of their greater utility, the latter because of their more difficult diagnosis. But, we repeat it the definition of a disease is only correct, so far as it comprehends all the forms which the latter is capable of presenting. — O. * Grimaud. Cours de Fidvres, vol. i., p. 2. NOMENCLATURE, SYNONOMY, ETYMOLOGY, OF DISEASES. 13 CHAPTER III. NOMENCLATURE OF DISEASES.—SYNONOMY.—ETYMOLOGY. I. Nomenclature. There is perhaps no science, the nomencla- ture of which is so defective, as that of pathology. This is doubt- less, in part, attributable to the very gradual progress made in the knowledge of diseases. If, like chemistry, the science of pathology had made a sudden and rapid advance, the old terms would have been replaced by others formed on more regular bases. But the case has been far otherwise, and nothing can be more preposterous than the collection of names by which diseases have been desig- nated. Some have been named from their known or supposed seat, as pleuritis and hypochondriasis; or from their causes, as colds, &c.; others from the places and seasons in which they ap- pear, as the camp, harvest and autumnal, fevers, (Grant;) from the country where they originated, as the typhus of America ; from the people who transmitted them, as the French disease, (a term applied by the Italians to syphilis;) from the animal which com- municates it, as vaccinia; others, from one of the principal symp- toms, as hydrophobia, chorea, &c. In eruptive diseases, the color of the skin has, in many instances, suggested the name by which they are designated; rubeola and scarlatina are examples. The word variola seems to have had the same origin, and to signify that diversity of color which the skin presents, when its surface is covered with white pustules, or yellowish or brownish crusts, sur- rounded by a red and sometimes brown areola, and separated by spaces in which the natural color remains unchanged. The par- ticular form of certain eruptions, the manner in which they are disposed upon the skin, their appearance during the night, have led to the adoption of names indicating these different circumstances, as miliaria, herpes zoster, epinyctis ; other affections have received names relating to their progress or duration, as intermittent, con- tinned, and remittent fevers. The insidious form of some diseases has caused the term malignant to be applied to them. There are others which have been designated, from a sort of resemblance to certain products of human industry, or some object of natural his- tory, as tympanitis, clavus, cancer, polypus, talpa, and elephantia- sis. Others have received names indicative of their supposed na- ture, as putrid and bilious fevers ; and again, indicative of the kind of organic alteration which constitutes the disease, as tubercle, melanosis, encephaloid disease; others have been named from the physician who first described them, as Potts' disease, Bright's disease. Besides these principal terms, some epithet indicating its degree of severity, form, termination or mobility, has been added to the name of the disease. Examples of this, are the variola benig- 2 14 NOMENCLATURE, SYNONOMY, ETYMOLOGY, OF DISEASES. na, apoplexia fulminans, tinea favosa, angina gangrenosa, febris ephemera, erysipelas erraticum. It is evident from this brief survey, that no rule has been ob- served in the selection of the names under which diseases have been described, and that incongruity prevails thoughout pathological nomenclature. But another and more serious inconvenience which it presents, is, that many terms are false, and consequently liable to lead to error; such are those based on the supposed seat of the disease, and upon its intimate nature. In some cases, the error is still more palpable, affecting some point relative to the origin of the disease, or some one of its more apparent phenomena. Thus, the disease of Slam, originated in America; the hepatic flux does not generally come from the liver, and the fluor albus may be of other colors, &c. The defects of such a nomenclature are too striking, not to have led many physicians to attempt their correction ; but it should be remarked, that these corrections have in nearly every case been partial, and that M. Piorry has been the first to propose a complete system of nomenclature for all diseases, established on uniform bases. These partial corrections, failing to produce a proper regu- larity, have proved rather injurious than useful. In some cases, more appropriate names have been substituted for those which were vague or erroneous, but the latter have not been totally aban- doned ; so that many diseases have received a variety of names, with which it is necessary to become familiar; no less than twenty have been applied to yellow fever. The effect of these numerous pathological terms, has been to increase the number of words, without aiding in the elicitation of truth. Another, and still more serious, inconvenience results from these partial corrections; some authors, not content with adding new names to the old, have transferred the same term from one disease to another, under the pretext that it was less appropriate to that to which it had been previously applied, than to the one which it was henceforth to represent. The troublesome results of these pretend- ed improvements are easily discernible; confusion in pathological language has been the necessary consequence. It will be perhaps asked, if, in the present state of the science, a new nomenclature could with advantage be established, and on what basis. When we consider the imperfections and incongruity of nomenclature, as it now exists, we become convinced of the im- portance of substituting a methodical nomenclature, which shall in- dicate the characteristic features of each disease, and by which we shall be enabled to establish their relations with each other. But if it be also considered, how much the difficulties connected with the study of the science become increased by such a multiplicity of names, and that, in the present state of our knowledge, it is impos- sible to present any system of nomenclature, which shall be satis- factory to all, as the attempts of M. Piorry sufficiently prove; and, lastly, if we regard the apparent contradictions to which new terms give rise, and the unfavorable inferences of the public with respect NOMENCLATURE, SYNONOMY, ETYMOLOGY, OF DISEASES. 15 to the certainty of medicine, we shall be led to conclude that the advantages of a new nomenclature would be more than counter- balanced by the inseparable inconveniences connected with it. " Si nunc imponenda essent nomina," says Morgagni,* " non dublto quin plura excogitari posslnt mellora et cum vero magls congru- entla; sed proestat, opinor, verum postea animadversum docere, vete?'a autem et usltata nomina retincreP There are some circumstances, however, in which it becomes necessary to add to pathological nomenclature; as upon the dis- covery of an affection not before described, and also when different diseases have been confounded under the same name. In both cases, it is indispensably necessary, even the enemies of neologism will admit, to seek a new name for the disease just discovered or pointed out. II. Synonomy. The same disease having, in some instances, received a variety of names, and the same name having been applied to many diseases by different authors, the study of the various names of diseases, with their different significations, has become also indispensable. This is, as it were, an artificial branch which man has added to pathology, without any real pro- fit, though not without necessity. Synonomy of diseases has con- sequently become a highly important point in their history, render- ing their study more complicated, an irremediable inconvenience, but enabling us to avoid much confusion. III. The Etymology of diseases is one of the least interesting points in pathology. It is, however, like many other things, a knowledge of which is of little utility, but ignorance of which would be attended with inconvenience. No one doubts that a physician may skilfully treat a disease, without being acquainted with the origin of its name; but it is equally certain, that it would be embarrassing, and even injurious for him to appear ignorant in the presence of some persons, of the etymology of a word which he daily employs. An acquaintance with the exact value of the terms in common use, is moreover convenient to the physican; medical phraseology would, otherwise, be to him unintelligible. Most of the names which have been applied to diseases, are of Greek and Latin origin; and as the study of these two languages should always precede that of medicine, it is rarely necessary for the physician to seek the etymology of the terms of which he makes use. The etymology of the various terms used in pathology but im- perfectly indicates the meaning which should be attached to them. It rarely gives an accurate, and often presents a totally incorrect idea of the disease. Thus the words phlegmqn, and phlegmasia^, from (p**Y<», ' I burn,' merely give the idea of heat, which is but one of the symptoms of the disease ; the word peripneumony, from moi, 'around,' and theuiiwi), 'lung,' indicates an affection seated around the lungs, whereas it consists in inflammation of this viscus itself, * Morgagni, Epist. xvi. 14. 16 SEAT OF DISEASES. and not of the surrounding parts. Thus, etymology, in the former case, presents an imperfect, in the latter, an erroneous, idea of the disease.* — O. CHAPTER IV. SEAT OF DISEASES. It may be remarked generally, that all the constituent parts of the human body are susceptible of some change, and consequently may become affected with diseases of greater or less severity. The susceptibility to the influence of the various morbific causes, varies in different organs; the skin and mucous membranes are of all tissues, those in which diseases are most frequently observed. The organs which are deeply seated, and which have no direct commu- nication with external objects, are less prone than all others to the acti6n of disease. It is not always easy to determine the seat of diseases, and the history of medicine shows how great has been the diversity of opinion on this point. During the reign of humorism,. the primi- tive seat of most diseases was supposed to be in some one of the fluids which enter into the organization of the human body. The Solidists, who came afterwards, supposed the humors to be purely passive in the phenomena of life, and considered the solids to be the seat of all diseases. Time has dealt justly with these erroneous opinions, and observation has shown that the exclusive claims of both these systems are alike inadmissible. It should be recollected that many diseases have a complex seat, primarily affecting the solid parts, and afterwards extending to the fluids of the body, or vice versa. The first stage of phlebitis pre- sents an example of a disease at first confined to a single tissue, but soon followed by a secretion of pus from the suffering part; this morbid product being carried along by the circulatory move- ment, is mixed with the blood, which becomes altered, and, by its effect upon other organs, produces phlegmasia^ and suppurations. In variola, on the contrary, and in the other contagious eruptive * Although the etymology of diseases is generally of slight importance, it is not in many cases devoid of interest. The names which have been given to diseases are often connected with the history of medicine, and the theories to which it has given rise ; such are the terms humoral fever, nervous fever. Etymology may also give rise to conjectures upon some of the circumstances relating to the particular history of a disease, &c. The term morbdli, for example, by which rubeola has been designated, would lead us to suppose that there appeared, simultaneously with it, another and more severe affection, bearing resemblance to it, which was called morbus, a name always given to epidemic diseases. This circumstance would add weight to the opinion generally entertained, that rubeola, which origi- nated in the same country with variola, first appeared at about the same period. SEAT OF DISEASES. 17 fevers, in which the blood appears to be the primary seat of the disease, the eruption makes its appearance upon the skin and mu- cous membranes, a few days after this alteration has taken place. There are some diseases which affect nearly all the tissues of the economy, as, inflammation, cancer, tubercles, and syphilis. Others are observed in but a few ; dropsy, for example, is peculiar to the membranes which line the interior of cavities, and to the cellular tissue ; spontaneous haemorrhage rarely occurs except from the mucous membranes. Haemorrhage may, however, take place in other parts, and dropsy may be formed, by means of accidental cysts, in parts naturally protected from it by their structure. There are also other diseases, which appear to be constantly and exclusively confined to the same anatomical element, wherever this be; this is probably the case in rheumatism and gout, which are peculiar to the muscular and fibrous tissues. Many diseases have a fixed seat, that is, they become developed and terminate in the same part where they originally appeared; others, on the contrary, successively invade the neighboring parts, as certain phagedenic ulcers, cancer, erysipelas, and perhaps most of the phlegmasia?, called spontaneous. There are others whose seat, which is essentially vague and moveable, is constantly vary- ing, as is observed in rheumatism and gout, the mobility of which affections constitutes one of their most essential characteristics. There are also certain nervous affections, which successively ap- pear in parts remote from each other, and haemorrhages are equal- ly liable to change their seat. There are many diseases which affect but a portion of the economy; there are others, which appear simultaneously in parts more or less remote from each other, exhibiting the same form and characteristics. The former have but a single seat, the latter are disseminated, or have a multiple seat. To the first belong the visceral and membranous phlegmasiae, as pneumonia or pericar- ditis ; to the second, urticaria, variola, rubeola, the syphilitic eruptions, morbus maculosus, &c. These latter affections, to which we have applied the term disseminated, deserve particular attention, from the conditions under which they are developed. These multiple lesions are indeed almost always secondary, and the physician may in most cases recognize the affection which gave rise to them, and to which the treatment should be directed. The organs which exist in pairs are often simultaneously affect- ed with the same disease. It is rare to see spontaneous ophthalmia confined to one of the conjunctivae, or bronchitis or emphysema affecting but one lung. There are certain chronic exanthemata which appear simultaneously in both armpits, in the two groins, and in corresponding parts of the same limbs. In rheumatism, corresponding articulations become generally successively affected. The same law is observed in regard to the deep seated organs. It has been clearly shown by M. Bizot, that the numerous changes which take place in the arteries, are almost always affected si- multaneously in the symmetrical vessels, and at corresponding 2* 18 SEAT OF DISEASES. points.* There are, however, some exceptions to this law; the two testicles, or the mammae, for example, which often become singly affected with inflammation or carcinomatous disease, are rarely the seat of either of these affections simultaneously. It has been long observed that the age has a marked influence upon the seat of diseases. During infancy the head is the seat of numerous affections; hydrocephalus, tubercular meningitis, the various eruptions of the hairy scalp, excoriations of the lips, nose and ears, apthae, grangrene of the mouth, and epistaxis are pecu- liar to this period; the lightest affections are accompanied with delirium, the submaxillary glands are often engorged, and the larynx is the seat of very serious diseases; it is at this period that croup is most commonly observed. At puberty and during the period of youth, affections of the chest, as inflammations of the pleura and lungs, haemoptysis, and bronchitis, become more frequent; it is then that the first signs of cardiac disease often manifest themselves, and so common is the occurrence of phthisis pulmonalis at this period, that it was for a long time supposed never to appear except between the ages of fifteen and thirty. While thoracic disease is more frequent during the period of youth, that of adult age is more prone to diseases of the abdomen; it is at this period that most organic affections of the abdominal viscera become developed; diseases of the stomach, intestines, ovaries, testicles, liver, bladder and uterus rarely occur before this time. The haemoptysis of youth, which succeeds the epistaxis of childhood, is followed in adult age by the haemorrhoidal flux, which is as peculiar to this period, as the others to the preceding. Lastly, in old age, while the abdomen continues the seat of various diseases, those of the urinary organs become more frequent, and the head again becomes prone to morbific action; dementia, paralysis, effu- sion of blood into the brain, softening of its substance, deafness, cataract, &c, are diseases as common during this, as they are rare at other periods of life. To this observation respecting the frequency of diseases of the head, chest and abdomen at particular periods of life, although generally true, there are numerous exceptions. Without referring to the diseases produced by mechanical causes, whose seat is determined by external circumstances, we often see children affected with pulmonary catarrh, phthisis, and various forms of enteritis. Scrofulous enlargement of the mesenteric glands, and intestinal worms, are of more frequent occurrence during child- hood than at other periods; mania, whose seat appears to be in the brain, is more common in youth and adult age; simple meningitis occurs at all periods of life, and pneumonia is one of the acute diseases most frequently observed in old age. But however nu- merous the exceptions, they are insufficient to invalidate the gen- eral rule. It has been stated that the seasons, as well as the age, exert * Memoires de la Soc. Med. d'Observation. Paris, 1836, t. 1, p. 399. ETIOLOGY. 19 a marked influence upon the seat of diseases; that in winter, cerebral diseases prevail; in spring, those of the chest; while ab- dominal affections are more prevalent in summer and autumn. This assertion does not so generally apply as the preceding, although not without foundation, particularly if it be considered with exclusive reference to acute diseases. Such are the general points of view, in which the seat of dis- eases may be considered, the difficulties and modes of deter- mining which, will be particularly considered in the chapter on diagnosis. —O. CHAPTER Y. ETIOLOGY, OR THE CAUSES OF DISEASE.* The most general signification of Etiology in all the sciences, is the study of causes; in medicine, its object is the knowledge of morbific causes. Under the title morbific causes, is included every thing which produces disease, and all that contributes to its development. The causes of disease are everywhere present, both around and within us. The things most necessary to our existence, as the air we breathe, the food and fluids which restore our daily loss of substance, the products of human industry by which life is rendered more comfortable and happy, themselves give rise to the ills with which we are afflicted. The different organs, which united, constitute the economy, and which are designed for the preservation of the entire system, of which they form part, may also, in certain circumstances, disturb its harmony; the muscles, whose use is to transport us from one place to another, may cause displacement and even fracture of the bones; the teeth, the eye-lashes, the nails, by their irregular development, sometimes occasion diseases of a more or less seri- ous nature; gestation, and especially the expulsion of the foetus, become under certain conditions the sources of danger and death. When we thus behold, within the system and without, the things most indispensable to human life and to the preservation of the species, become in some circumstances the causes of the maladies by which we are afflicted, we are tempted to admit with Testa, that there is not, properly speaking, any morbific cause, nothing in itself injurious: " Nihil proprie morbificum, nihil noxium natura sua." But this assertion, although true in respect to the greater number of causes which disturb the health, becomes the opposite, when, reviewing all the causes of disease, we come to *Ahia, cause ; loyog, narration. 20 ETIOLOGY. the contagious principles, which are certainly, in themselves and despite the abuse that may be made of them, morbific agents. The causes of disease being very numerous and varied, the necessity for a division of them has always been experienced : they have been divided into external, or those which surround the individual; internal, existing within him; principal, or those which act an important part in developing diseases ; accesso- ry, which exert but little influence in their production; remote, which prepare or determine the hidden alteration constituting the essence or proximate cause of the disease; predisposing, which gradually modify the economy and dispose to various affec- tions ; occasional, which provoke the development of such affections. The terms physical and chemical, have been applied to those causes which act in accordance with the laws of physics and chemistry, and which would affect the dead equally with the liv- ing body: such are instruments capable of inflicting wounds, caustic substances, etc.; the term physiological is applied to those which need the co-operation of a vital reaction in the organ which receives their impressions; local, to those whose action affects but a portion of the economy ; general, to those which ex- tend their influence over all; negative, to those which consist in the abstraction of conditions necessary to health; and the oppo- site, positive, to those which act by their own power in the pro- duction of diseases. Material and immaterial causes have been admitted, according as they are or are not recognized by our senses. Finally, as there is a certain number of diseases which occur without appreciable cause, concealed or occult causes have necessarily been admitted, and these have been ascribed by many authors to certain inappreciable qualities of the atmosphere, to which the development of epidemics may be attributed. There are serious inconveniences attending each of these divis- ions. The proximate cause, which is nothing else than the very essence of the disease and the peculiar modification of the organism which constitutes it, cannot be reckoned among the causes which produce it. Among the occasional causes, circumstances entirely dissimilar are enumerated: the impression of cold, for instance, which at one time developes pneumonia, at another, occasions anasarca, and which most frequently is productive of nothing morbid, is placed in the same category with wounding instru- ments and poisons, which always produce definite effects upon the system. It is unnecessary to insist upon the imperfection of each of these divisions ; neither of them possesses the advantage of uniting those causes which have an analogous action; and yet it is this very circumstance which should serve as a foundation for the most natural division of morbific causes. Among these causes there are those which are constantly fol- lowed by the same diseases; for them we reserve the name deter- mining. Others, whose action is often uncertain and always ob- scure, may be subdivided into two series. In the first, we place ETIOLOGY. 21 whatever serves, by gradually modifying the economy, to pre- pare it for any particular affection, and everything constituting the aptitude for being so affected : these are predisposing causes. In the second series we rank those whose action, usually tran- sient, only hastens the development of a disease, to which the patient was predisposed : to the latter we give the name occasion- al or exciting causes. Thus we admit three orders of morbific causes, which we dis- tinguish by the appellations determining, predisposing and occa- sional. We shall rapidly review the chief causes which belong to each of these three divisions, and shall afterwards offer some general considerations upon their mode of action in the production of disease. ARTICLE FIRST. Determining Causes. Determining causes, which constantly give rise to the same af- fection, if we except certain conditions more or less well known, exhibit in almost every instance, either in themselves or in the dis- ease which they produce, some peculiarity. The hot body which burns, the cold which freezes, the gases which poison or cause asphyxia, the body which inflicts a wound, the poison which nar- cotizes or causes convulsions, are certainly special causes, in like manner as the diseases which they induce are themselves unlike all others. This it is which led us in the former editions of this work, to class these morbific agents among the specific causes, and to use synonymously the terms specific and determining causes. Notwithstanding, we now think that a more strict signification should be given to these words, and one more in accordance with general usage : by specific causes, then, will be understood those which produce specific diseases, and by specific diseases, those which cannot be developed except by one and the same cause, as syphilis, rabies, variola. Those causes whose action is equally di- rect and constant, but which give rise to diseases which other causes may also produce, will be designated common determining causes; burns and wounds, for instance, may be produced by vari- ous agents. We may add, that the greater part of the common determining causes act by virtue of physical or chemical laws, and that their action can be explained by these laws. Specific causes, on the contrary, in their mode of action, are inexplicable, either by means of physics or chemistry. Such are the motives which have induced us to divide these two classes of causes and to study them separately. § I. Common determining Causes. These may be diffused in the atmosphere {circumfusd), brought in contact with our bodies, (appllcata), or introduced into our organs (ingesta); they may exist within us and depend upon derangement of the evacuations 22 ETIOLOGY. {excreta), of the movements (acta) or of the perceptions {percep- ta) ; they will be pointed out in this order, which is the one most commonly followed in the explanation of hygiene, and which is equally well adapted to the study of morbific causes. A. Circumfusa* In certain circumstances gases unfit for re- spiration are introduced into the air passages; nitrogen, the pro- toxide of nitrogen and hydrogen have been inhaled by chemists in order to ascertain their effects on the animal economy. They produced a mild asphyxia very different from that caused by the deleterious gases. These last are sometimes found accumulated accidentally in certain places where the external air penetrates with difficulty; as in drains, sewers, mines, certain work-shops, facto- ries, and in some thermal establishments. Carbonic acid gas and carburetted hydrogen, which are disengaged by the combustion of charcoal, may become mixed with the air in sufficient quantity to asphyxiate the persons who breathe them. The same is true of the gases which escape from animal matters, particularly excrement in a state of putrefaction, in a closed vault, by which asphyxia is quickly produced. This accident, to which the workmen, who are employed in clearing privies are exposed, is occasioned by a gas long known as sulphuretted hydrogen, and which seems most commonly composed of hydro-sulphuric acid, hydro-sulphate of ammonia and nitrogen. Carbonic acid gas accumulated in the lowest part of certain caverns, (as in the Grotto del Cane, for in- stance) is in that situation several feet in depth; if a man enter, he is above the level of the deleterious gas, but a child would be asphyxiated, like the animals which are introduced for experiment. Putrid and malignant fevers have at times raged epidemically during the disinterment of a large number of bodies: the town of Saulieu, in 1773, presented a sad example ;f and long previously, an epidemic, gangrenous fever had been observed,! produced by tainted air after contagious disease among animals, where great numbers of their bodies remained unburied and infected the at- mosphere. Vegetable emanations are occasionally the determining causes of disease. Air charged with the odorous principle of the hyacinth, the lily, the orange blossom, the narcissus, causes headache, nau- sea, dizziness, and sometimes even fainting, especially in small and warm apartments. A very high, or exceedingly low temperature of the atmosphere is a determining cause of many affections. Individuals exposed to severe cold have often been observed to die with symptoms which might be ascribed to asphyxia or to strong cerebral congestion; * Properly speaking, morbific agents, diffused in the atmosphere, act only by their introduction into our organs, and, thus considered, should, perhaps, be ranked with the ingesta; but it has not been tfeemed proper to depart from the classifica- tion generally adopted. f Maret, Usage d'enterrer les morts dans les eglises. Dijon, 1775. | De recondita febrium remitt. ac intermitt. natura. ETIOLOGY. 23 freezing of a portion of the body is at such a time a yet more fre- quent occurrence. The grave symptoms caused by a very elevat- ed temperature have also been referred by most physicians to apo- plexy or asphyxia; but, from the researches of some authors, and those of J. J. Russel in particular, it seems that the special action of heat is a determination towards the thoracic organs, causing vi- olent congestion, frequently terminating in death.* A very brilliant light suddenly flashing upon the eye, or an ex- ceedingly loud noise, may produce blindness, or deafness. A violent discharge of electricity diffused through the air, or col- lected by apparatus, has caused in some persons sudden death, in others, incurable tremor, stupor, or partial paralysis. B. Among the applicata a great number of determining causes exist. Those bodies which inflict bruises, and pointed and cutting instruments, are the most common causes of all the wounds to which man is exposed. Falls, in which the human body^trikes with the impetus it has received, against surfaces more or less resistant, give rise to diseases, analogous to those produced by vulnerary agents. In the same class with these latter must be placed ligatures, which, in addition to their hindrance of free circulation, may pene- trate into the tissues when strongly drawn, and asphyxiate when applied over the course of the trachea. Immersion in a liquid has a similar effect by preventing the ingress of air. Incandescent bodies, and boiling liquids placed in contact with our flesh either inflame or cause gangrene, ac- cording to their degree of power. Solid or liquid caustics, acids, alkalies and salts, act in an analogous manner ; some of these sub- stances, as corrosive sublimate and arsenical preparations, may be absorbed at the surface of the body at the same time that they act locally as caustics; they may likewise be conveyed into the in- ternal organs and give rise to the phenomena of poisoning. In the same series may also be placed the acrid topical agents, whether rubefacient or vesicant, as the flower of mustard, the powder of cantharides, the bark of the Daphne Mezereum, etc., etc. C. Ingesta. Substances introduced into the interior of the body, become frequently the determining causes of disease. The poisons belong almost wholly to this class. By poiso?is are under- stood, according to Mead, all those substances which, in minute doses, are capable of producing great changes in living bodies. We prefer, with Mahon, to give the name to those only which are destructive of life. Formerly, poisons were divided into mineral, vegetable and ani- mal. M. Orfila has, with reason, considered it more convenient to class them according to their mode, of action upon the economy, rather than after the particular natural kingdom to which they * Encycl. des. Sciences Medicales p. 235. 24 ETIOLOGY. belong. Consequently, he has divided them into four classes, according to their properties, viz., irritating, narcotic, narcotico- acrid and septic. Irritating, corrosive, escharotic or acrid poisons, according to their strength, simply inflame or completely disorgan- ize the part to which they are applied. Narcotic poisons, such as opium, the solanaceae, etc., act in an entirely different manner: their operation is particularly upon the brain, whose functions they disorder or suspend, and they have but little effect upon the organs with which they are in immediate contact. Narcotico- acrid poisons, such as the poisonous mushrooms, present the above two modes of action united. Finally, septic poisons, as the flesh of animals who have died of pestilential diseases, putrifying animal matters, and certain products of morbid secretion, bring on grave disease of an adynamic or ataxic form, often complicated with gangrene, and most usually terminating fatally. Ergot, which produces gangrene of the tissues, must be classed, for this reason, with the sqptic, rather than with the narcotico-acrid poisons. D. There are but few determining causes among the excreta, the gesta or the percepta. A very abundant natural haemor- rhage, particularly if menstrual, may bring on anaemia. A strong muscular contraction may rupture a tendon, or break a bone: it is often the determining cause of hernia, and sometimes of dislo- cation. Very powerful moral affections, as disappointed love, or nostalgia in adults, and chagrin in children, are sometimes the de- termining causes of a species of hectic fever. A deep-seated pas- sion is commonly the determining cause of melancholy. Despair, terror, and immoderate joy, have, in some cases, caused sudden death. There are some diseases which may become the deter- mining cause of certain others. Thus, severe parotiditis has sometimes produced asphyxia; a fracture or a dislocation, the formation of enormous abscesses in the cellular tissue; perforation of the stomach, rupture of the gall-bladder, the urinary bladder. the uterus, the erosion of the intestines by ulceration, and of the pleura by softened tubercle, are so many direct causes of peritonitis or of pleurisy almost inevitably fatal. Retention of faecal matter in the rectum, has sometimes occa- sioned all the phenomena of intestinal occlusion, and in some rare cases has caused death, especially in aged patients. Finally, the presence of certain parasitic animals in the human body, may be added to the above determining causes, as taenia, the oxyuris, the ascaris lumbricoides, hydatids, etc. Their exist- ence does not always produce morbid phenomena, but is, in itself, something abnormal as regards the material disposition of the parts. Consequently, it constitutes a disease which will always be the same in its essence, however varied may be its form. It is the same with inanimate foreign bodies, introduced into our organs by the natural passages, or by the medium of a wound; although their presence may occasion no disturbance of the health, we must, nevertheless, class them with the determining causes be- ETIOLOGY. 25 because they act in a uniform manner; the point of an instrument or a ball remaining in a wound, or a foreign body in the trachea, evidently belong to this class of causes. Specific determining Causes. The peculiar character of these, as was mentioned, is the production of diseases, which they alone can cause, and the impossibility of explaining them by physical or chemical laws. They are subdivided into two distinct series, according to their mode of action : to the first, belong those whose effects are confined to the individual who is exposed to their influence; to the second, those morbific agents, which, like seeds, reproduce themselves in the course of diseases to which they give rise; so that the indi- vidual affected by them, propagates them in turn, and may trans- mit them to other persons; hence arises the necessity of sub- dividing specific causes into common and contagious. Common specific Causes. This series consists of certain me- tallic emanations, some of the poisons, miasmatic exhalations, and the venomous secretions of animals. Those who work in lead, painters, smelters of metals, those who grind colors or prepare the carbonate and red oxide of lead, etc., are subject to a disease known as lead colic, an affection, which differs sufficiently from all others to which the digestive tube is subject, to be ranked among the specific diseases. The colic caused by copper, on the contrary, closely resembles the inflammation resulting from external causes. Therefore, notwith- standing the similarity between these two kinds of colic, we must refer the action of copper upon the economy, to common determining causes, while the preparations of lead will come under the head of specific causes; in like manner mercury and its compounds belong to this second series, in consequence of their entirely specific influence upon the mucous membrane of the mouth, {stomatitis, or mercurial salivation.) Strychnine and brucine, which cause tetanic convulsions, such as no other known sub- stance can produce, may with propriety be classed with the specific morbid agents. Miasmatic exhalations constitute another group of morbific causes, which reason would induce us to admit, but whose exist- ence even, has not, as yet, been confirmed by physics and chem- istry, much less their nature and effects determined. We shall refer them to two classes, according to their origin. The first spring from the decomposition of dead vegetable and animal matter, in moist or marshy places, and in stagnant water. These are styled marsh miasmata, the effluvia of marshy grounds: if it is borne in mind that intermittent fevers prevail habitually throughout the regions where the conditions which cause such decomposition exist; that these fevers make their appearance towards the end of summer, when the receding water has exposed its basin, formed chiefly by the remains of de- caying substances; if it be remembered that these affections have 26 ETIOLOGY. always disappeared upon the drying up of the marshes ; that they show themselves only momentarily in most of those places where pools of water are accidently formed ; if we notice that they are very frequent and exceedingly grave in the localities nearest to standing water, and become more rare and less severe in propor- tion as we remove farther from such places; finally, if we regard the influence which the winds in the neighborhood of marshes have upon their development,* we cannot but admit the existence of these miasmata, and the part which they play in the produc- tion of intermittent fevers. Our authority for ranking the marsh miasmata among the specific causes, becomes the higher, from the fact that the specific character of the diseases which they produce, is demonstrated by the specific character of their remedy. There cannot be a specific remedy, except for those diseases which recog- nize one and the same cause. The other species of miasmatic exhalations is derived from liv- ing beings, healthy or otherwise, but chiefly from those diseased, when collected in too large numbers in confined places. The peculiar developing causes of infectious disease most often exist united, on board vessels, in prisons, campSj hdspitals, and be- sieged cities, and these are the conditions which cause a great number of diseases to rage with the most intensity; they have been described as putrid, malignant and pestilential affections. Almost all of them belong to the different kinds of typhus and to dysentery. By general agreement, they are deemed to be owing to the alter- ation of the air by the miasmata, and to the infection of the economy by it when thus vitiated; by infection is understood the action exercised by these causes, and the resulting diseases are termed infectious. Venomous secretions must also be classed among the specific causes of disease. These are peculiar to certain species of ani- mals, and serve as their natural means of attack and defence: when deposited by the animal secreting them, in the wounds which it. inflicts, they occasion the same sort of affection in every instance. The viper, the wasp, and the bee, in our climate, are the only creatures provided with apparatus fitted for the secretion and deposition of these poisons. In warmer climates, the scor- pion and various kinds of serpents possess far more deleterious qualities. Venom differs from virus in many respects. The latter, as we shall hereafter see, is only produced accidentally, by diseased individuals; the formation of venom, on the contrary, is continual, and is not connected with any functional disturbance : virus acts slowly, and reproduces itself in those affections to which it gives rise; the effects of venomous secretion are prompt, and not trans- mitted from the one who suffers by them, to others. § II. Contagious Principles. There is a certain number of diseases which may be transmitted from the affected individual * Lancisi, Senac, Alibert ETIOLOGY. 27 to healthy persons, who are in communication with him. This transmission of disease arising usually from direct or indirect contact, has been called contagion; and the epithet contagious is applied to diseases thus transmitted. We are ignorant of the modus operandi of contagion; neverthe- less it is probable that it takes place by means of a material agent whose existence cannot be called in question, although it escapes our perceptions: this agent is called the contagious principle or virus. Although not recognized by our senses, the contagious princi- ples have been made the object of special research by some phy- sicians. The following is the opinion of most pathologists upon this point. The invisible principle which causes contagion, is usually enveloped in a visible substance, as mucus, serous fluid, pus, (either liquid or dried into crusts.) and the matter of cutaneous transpiration. These different substances not being contagious in themselves, it is supposed that they do not become so, in certain cases, except by mixture with this subtle and unattainable matter, which is the agent of the contagion. At all events, it is not impossible that the pus and mucus may become contagious in themselves, by reason of the alteration effected in their essential nature. However this may be, the following are the chief characteristics of contagious principles : By means of a constant series of morbid phenomena, they all reproduce principles similar to themselves, and capable of causing the same effects. They maybe multiplied ad infinitum, by means of this secondary development, so long as they meet with bodies capable of fully receiving their action. Indeed, we doubt the ex- istence of any virus whose contagious properties become extinct after the second transmission, as some have endeavored to prove in regard to rabies; nevertheless, we do not hesitate to admit that some kinds of virus, by continual reproduction, appear to become enfeebled'in their action; for example, the syphilitic virus and that of the plague. Some of these contagious principles destroy, either temporarily or entirely, in the individual who experiences their effects, the susceptibility of being again affected; such are those productive * Hufeland defines contagion, or the contagious principle, to be a subtle mat- ter which insinuates itself into the living body, and which may there excite a definite form of disease. The marsh miasmata are, according to him, and by the above definition, contagious principles, as well as the variolous and syphilitic virus. He admits two sorts of contagion, the living and the dead. " The first is produced by a living body ; it may occur in all those diseases where the humors have acquired a high degree of putridity, and when there is a specific change in the state of the secreting organs, as also in that of the humors which they secrete, as in measles, scarlatina, dysentery, etc The other sort of contagion, is that derived from the exhalations of inanimate bodies ; such are the marsh miasmata, the foul air which causes catarrhal fevers, etc. 28 ETIOLOGY. of typhus, small-pox, scarlatina and measles: others have seemed to increase rather than diminish this liability to renewed attacks: the syphilitic virus is one of these. In other words, some conta- gious diseases attack the same person only once during life; others, which are the exception, reappear at the end of some years; finally, others occur in those who have before been affected by them, more readily than in those who had previously escaped their effects. It is supposed that a certain proportion of the contagious princi- ples are produced without cessation during the entire course of the disease, while others only arise during a certain part of it; but this opinion is not yet sufficiently proved. The different modes of contagion have been likewise the object of particular research ; it may be immediate, or communicated by an intermediate body. Contagion is immediate when its principle is directly transmit- ted from the person who originates it to the one who receives it and experiences its effects ; this immediate transmission may occur in many ways : 1st, by remaining in the sick room when the air is charged with contagious principles, as appears to be the case in the transmission of typhus and perhaps of variola. 2d. By actual contact, as is observed in most diseases of this character. 3d. By still closer contact, as in the transmission of pestilential, vaccine and syphilitic virus, which are inert upon the sound skin, and cannot be communicated except the epidermis has been previously removed or destroyed, or the virus deposited upon a mucous mem- brane. 4th. Immediate communication, also, may be effected by means of the remains of animals destroyed by the disease which engenders the contagion: it is in this way. that the. malignant pustule is communicated to those who dress the skins, or handle the wool of such animals, &c. Mediate contagion arises through the agency of substances which have been in contact with the patient's body, as his clothes, and the various utensils employed about him. It has been remarked that among the substances which most readily receive and transmit contagion, woollen, silk, cotton and linen, hold the first rank; a strong affinity for these materials has been ascribed to the conta- gious principles, which are retained by them a long while, espe- cially when kept from the air. Those holding communication with the sick may transmit contagion without being themselves af- fected ; and flying insects, alighting in turn upon the patients and upon healthy individuals, have been supposed to carry to the latter the virus which they had drawn from the former. The circumstances favoring contagion, or the action of contagious principles, have been carefully examined. It is considered highly important that the contagious principle be of recent origin ; its power diminishes gradually in the course of time ; for instance, it has been proved by numerous experiments, that the pus of variola, after the lapse of a year, becomes less energetic, and at the end of three, is no longer contagious. Hildenbrand supposed that the ETIOLOGY. 29 contagious principle of typhus did not exist beyond three months, because, according to him, no epidemic typhus is reproduced after that lapse of time, without the concurrence of new causes. Temperature also has a great influence in facilitating the trans- mission of contagious diseases ; the degree of heat peculiar to the human body seems most favorable to contagion, and the nearer the atmospheric temperature approaches this standard, the more easily are contagious diseases propagated. The sudden disappearance of pestilential disease when the temperature is below freezing, has led to the supposition that the contagious principle was susceptible of congelation. It has also been thought that these principles might be destroyed or burned, as it were, by extremely elevated temperature; and those physicians who enumerate yellow fever among the contagious diseases, have supported the theory of the decomposition of virus by heat, by the fact of the sudden cessa- tion of that disease in the torrid zone, when the atmospheric heat attains an unusual degree of intensity. M. Bulard has observed the same in regard to the plague of the East. The frequency of typhus in winter and its greater violence at that season, seem to invalidate the assertion that we have lately made, viz., that a tem- perature approaching that of the human body would be the most favorable for the transmission of contagious diseases. But if we reflect that the number of sick soldiers is much greater during winter campaigns, and that the cold weather renders it indispensa- ble to quarter them in places partially or entirely closed, where in a short time they become crowded, we shall understand that if epi- demic typhus is more frequent and destructive in cold and wet seasons, it is not owing to the cold, but to the concurrence of those injurious circumstances which have just been mentioned. Still farther, it has been remarked that dampness, absence of light, and animal emanations favor the transmission of contagious disease. Besides these general circumstances which assist the action of contagious principles, there is a certain number which are peculiar, and which exercise the same influence ; such are youth and adult age, an impressible and delicate constitution, want of food, absti- nence from alcoholic drinks in persons who have habitually used them; the weakness accompanying convalescence, fear, discour- agement, terror, errors in diet, excessive evacuations, and the state of sleep. Man is, almost constantly, the source which begets and perpetu- ates the greater part of the contagious principles with which we are acquainted. There are, however, some which seem not to be spontaneously developed in him, but to be always transmitted by animals; such are rabies, glanders, and the vaccine disease. Among contagious diseases, or those considered as such, there are several which originated upon this continent, typhus fever and the itch are examples ; there are others which have been imported ; variola, scarlatina and measles originated apparently in Asia; the 3# 30 ETIOLOGY. plague, in xlsia or Africa; syphilis and yellow fever were proba- bly brought among us from America.* The primitive formation or generation of contagious principles is shrouded in great obscurity. Some physicians think that having been generated at one particular time, they have ever since been reproduced by means of transmission only. This opinion is, however, inadmissible. It is true that the conditions under which many of these principles are developed, are unknown ; but still we must allow that they can, and must be, reproduced by a con- currence of causes resembling those which first brought them into being. The history of European typhus, and its reproduction under the action of well known circumstances, exemplify this opinion, and lead us to suppose that there must be some analogy in the development of exotic poisons, as those of the plague, variola and syphilis. But if, as everything would induce us to think, these different sorts of virus did not originate in Europe, if they were first * Were not the incompatibility of this assertion with the date of the first appear- ance of syphilis, in Europe, sufficient to prevent its incorporation into the present work, even in the slightly qualified terms used by the author, it would seem that the concurrent testimony of the best authorities of more remote times as well as of our own, would have rendered its insertion impossible. Jourdan, long since, suf- ficiently disproved the opinion of the American origin of syphilis, and by an elabo- rate comparison of dates showed the utter impossibility of its having been imported into Europe, according to our author's supposition. But it is unnecessary to re- peat his widely known observations, or even the apparently well-founded opinions of many others who date the origin of the disease as far back as the days of Old Testament narration ; among these are B. Bell andM. Cazenave, cited by Grisolle in his late work upon Internal Pathology,1 who himself also, although he considers the question undecided, evidently leans toward the ancient origin of the disease, and mentions a statute of Jeanne the First, Queen of the Sicilies, relative to medi- cal inspection of prostitutes diseased in their genital organs ; this was in 1347,— and no author has pretended that the disease was imported before the arrival of Columbus and his companions from America in 1493. Oviedo, one of the cham- pions of the importation doctrine, mentions its appearance in America in 1498, which is after its manifestation at the siege of Naples, by Charles VIII., the con- quest of which city was effected in 1495. Some have asserted its existence at Paris, in 1494. It is likewise stated to have been "raging" at Rome, and in other parts of Italy in June, 1493, and even supposing the possibility of its having been carried to that country by the followers of Columbus, who arrived from America only two months previously to the latter date, is it reasonable to suppose that it could have been raging in various parts of the country so soon? Besides the importation by these men in that space of time, is not proved. Hunter, Spren- gel, Pearson and Bacot, among others, have lent the powerful influence of their names and arguments against this doctrine. M. Cazenave, of all modern writers, perhaps, uses the strongest language, and furnishes the most irresistible proof in re- gard to what he considers the ''fable " of the American origin of syphilis. Some account of his views may be found in the British and Foreign Medical Review for April, 1817, pp. 346, 347. Why is it not reasonable to suppose that promiscuous copulation in any country and among the most cleanly people, might engender disease of the genital organs ? But was it less likely to occur among the dirty aind depraved soldiers of a European army, and the luxurious profligates of the higher classes than among the inhabitants of America, simple in their habits, and, as it were only on the borders of civilization 1 — Trans. 1 Path. Int., vol. ii. p. 23. De La Syphilis ou Maladie Venerienne. ETIOLOGY. 31 generated in other countries and with an assemblage of conditions nonexistent among us, we must suppose, whenever we observe them, that they are owing to contagion, even when we cannot point out the individual from whom it emanated. Among exotic poisons, many are acclimated on our con- tinent ; they appear there without interruption, and produce at intervals, (doubtless with the concurrence of favorable atmospheric conditions,) epidemics of greater or less severity : variolic virus and that of scarlatina and measles, are examples. Other conta- gious diseases, or those so reputed, as the plague and yellow fever, manifest themselves, as it were, only momentarily : they usually disappear, after having committed their ravages for some seasons. Linnams published, in the Amenites Academiques, a dissertation wherein he endeavors to establish that all contagious diseases are owing to animalcules, which, by being transported from the infect- ed to the healthy, transmit the disease, which is but the effect of their presence. The foundation of this theory may be seen in the work above mentioned; some very curious details, especially, will be found, relative to the form and habits of the acarus dysen- terlce, but these are foreign to our purpose. The interesting researches which have since been made, have firmly established this opinion, as regards the itch; the existence of the acarus scabiei, is now demonstrated; but there is no reason for supposing any- thing analogous in other contagious diseases. Such are the chief morbific causes, which, brought into action upon the economy, invariably produce the same effects. Their mode of action will be hereafter considered. ARTICLE SECOND. Predisposing Causes. According to the course generally agreed upon in the methodical study of all sciences, we have thought proper to speak first of the most apparent causes of disease; at present, we intend to examine those which are the least so, commencing with those called pre- disposing, which, as we have said, act by degrees upon the econ- omy and prepare it for various affections. Their action is almost always obscure and often questionable. All that we shall say therefore, upon this action, must be considered as a collection of generally admitted opinions on the subject, rather than the con- sequence of facts rigorously observed, or the expression of our own conviction. Some of the predisposing causes extend their action to a great number of individuals at once, as to the entire population of a city, a province or an empire; sometimes to large collections of men encamped, or in navies, hospitals and prisons; they favor the development of similar, or analogous affections in all who are 32 ETIOLOGY. exposed to their influence: we shall style these, general predis- posing causes. Others act only upon isolated individuals: these may be called individual predisposing causes. The principal morbific causes belonging to these two series, will now be briefly enumerated. SECTION FIRST. General Predisposing Causes. The general predisposing causes are, for the most part, diffused in the atmosphere, or arise from certain local conditions. Atmosphere. The air has a very decided influence upon the human body: this is, however, limited, and it does not at all follow that the state of the economy should be entirely subordinate to that of the atmosphere, as some physicians have pretended.* The frequent changes of the atmosphere are occasional rather than predisposing causes of disease. It is more particularly, when for a long time in the same state, that the air seems to produce modi- fications in the human body, from which result various predispo- sitions to disease. A cold and dry air predisposes to deep-seated inflammations, and active haemorrhage, and gives to the greater part of acute affections which may be developed, their character, or what has been called inflammatory nature. A warm and dry air hastens the development of superficial inflammations, as erysipe- las, and the exanthemata, and often gives to acute disease the form termed bilious. Affections of the mucous membranes and those called adynamic, prevail under the influence of a warm and moist air: catarrh, scurvy and rheumatism occur more particularly when the atmosphere has for a long while been moist and cold. In our climate,! the north and east winds are almost always dry and cold; the south-east dry and warm; the south-west is of a warm and moist temperature; the north-west is cold and moist. The influence of these winds in the production of dis- eases is the same as that of the different qualities to which they correspond. Air which is not renewed, quickly becomes vitiated, as may be remarked in confined apartments, especially in dungeons and subterranean passages. Man cannot remain long in such places without, experiencing injurious effects ; his functions languish, his * Talis est sanguinis dispositio, quails est air quern inspiramus. —Ramazzini de Constitutione, anni 1691. f The reader will of course perceive the necessity of adapting the above remarks in regard to the influence of the winds, to " our climate ;" our differ- ent position, as respects the ocean, changing wholly the nature of that influence : as for instance, the north and east winds with us, are almost uniformly moist and cold : the term "dry" is almost never applicable to our south-east wind although it may, sometimes, be " warm ; " our south-west winds are warm and' dry, and our north-west, cold and dry. — Trans. ETIOLOGY. 33 constitution becomes enfeebled, and chronic affections of different kinds are developed. The stagnation of the air in the ravines of the Valais, appears (from the researches of Fodere) to be the principal cause of the frequency of goitre in that country. Considerable variations in atmospheric pressure may also be considered as causes of disease. Examples are cited of ocular haemorrhage, of epistaxis and haemoptysis determined by a dimi- nution of the weight of the air, produced either by a change supervening in the atmosphere, or because the individual, being elevated into a higher region, was submitted to the pressure of a smaller column of air. The diminution and increase of atmos- pheric pressure have also been declared equally powerful causes of cerebral congestion and apoplexy. Deprivation of light disposes to anasarca, to scurvy and scrofu- la, and always gives rise to a sort of etiolation, similar to that produced by the same cause in vegetables. The researches of M. Edwards also go to prove that the action of light is necessary for the development of the body, and that its withdrawal may be considered one of the external causes productive of deformity in scrofulous children.* This agrees also with the generally admitted opinions upon the etiology of these affections. Hildenbrand has likewise remarked that absence of light greatly favored the contagion of typhus.f Does electricity diffused in the atmosphere, aid in developing disease, as some modern physiologists have asserted? Can we admit the existence of a nervous fluid analogous to galvanism ? Does it follow that vital power is increased when positive elec- tricity is in excess; that it diminishes when negative electricity is most abundant, in low and moist localities, before storms, in warm seasons, and with a west wind ? These purely hypotheti- cal opinions are not suitable for present discussion. As Hippocrates remarks, all diseases may manifest themselves at any time of the year; nevertheless, the natural changes which supervene in the atmosphere, by reason of the succession of sea- sons, influence very powerfully the development of many among them. This influence, which has been recognized from the earliest days of the science, has been confirmed by physicians of every age. Hippocrates remarked a uniform character among summer diseases ; he likewise noticed some analogy among those of winter,^ and he comprised among the former, the complaints common in the latter half of spring and the first half of autumn ; and in the second class, those of the last of autumn and of the early spring. In our climate, more resemblance exists between the diseases of spring and of the months preceding and following that season, than between those of summer and the neighboring * Influence des Agens Physiques, pp. 401 et 402. f Typh. conta. X Aphor. lib. iii. 34 ETIOLOGY. months; the same observation applies to the complaints of autumn and winter, and those of spring and autumn form sepa- rate groups. The progress of the former is more rapid, their ter- mination more complete, their duration less; in them, relapse is not so common, and remedies are more efficacious. The develop- ment of the other class is more gradual, their continuance far longer, and sequelae of a bad and obstinate nature often succeed them; they do not yield as readily to treatment, and are more easily reproduced after momentary suspension. This difference has been particularly observed in intermittent fevers, vernal or autumnal; but it is by no means a rule of constant application. In our climate, the number of grave diseases is uniformly more considerable, and the mortality greater, in spring than in au- tumn. In addition to the above marked differences which these two opposite periods of the year cause in disease, it has been observed that each season has, in like manner, a less noticeable, but still an incontestible influence.* Winter, with a dry atmosphere, usually predisposes to inflam- matory complaints, active haemorrhages and cerebral congestions ; when wet, to affections of the mucous membranes and chronic discharges. In summer, bilious diseases, cutaneous exanthemata, cholera morbus, mental alienation and various other neuroses, prevail. Autumn apparently contributes to the development of mucous and rheumatic affections, dysentery and intermittent fe- vers, which are more frequent at this season than at any other. Spring almost always abounds in inflammations of the throat and chest, and in haemorrhages, etc. The influence of the moon, and fixed stars, upon the develop- ment of disease has often furnished physicians with matter for dis- cussion. If these bodies exert no action upon the temperature and moisture of the air, it is very likely that they have none upon the animal economy. But if, as many natural philosophers have as- serted, tides, storms and the course of the winds are subject to the influence of lunar changes, the moon might possibly have a direct action upon the economy; an indirect effect might, at least, be demonstrated. Localities. There is no part of the earth which is not habitable by man. But although capable of inhabiting every place, he can- not escape the influence which is thus exerted upon his constitution or the morbid modifications communicated. In southern climates, * Some physicians, supposing they had observed that the principal changes caused by the seasons in prevailing diseases, did not correspond exactly to the divisions of the common year, proposed to form a medical year, in which spring should commence on the twelfth of February ; summer on the twelfth of May ; autumn in August, and winter in November; but, as there is no regu- larity in the period when the so-called vernal or autumnal diseases appear, as their manifestation even, is not constant, it is more reasonable to continue the usual ljmits to each great division of the year, and to the words in common use their general acceptation. ETIOLOGY. 35 tetanus, yellow fever, and many diseases wholly unknown at the north, prevail; in the opposite latitudes, inflammatory affections are very frequent: in temperate climes a greater variety of disease exists. In dry and elevated districts, men are exceedingly subject to all the acute affections; chronic complaints, on the contrary, pre- vail in low and wet countries. This influence of elevated position may be easily verified in cities built both on high and low ground ; in the upper portion, diseases are rare and of very rapid progress; in the lower, they are more frequent and tend to the chronic type. A northern or eastern exposure, or a southern or western one have the same influence in the development of disease, as the winds blowing from either of these directions. (Page 32.) City and country life dispose to very different affections. The neuroses, scrofula, rachitis and pulmonary phthisis are far more frequent among the inhabitants of cities than among those residing in the country ; a country population is more exposed to acute dis- ease, and chronic affections are rare. A residence in hospitals, prisons, vessels, and barracks apparently predisposes to dysentery, scurvy and different kinds of dropsy. Change of abode likewise becomes a general predisposing cause for sailors and soldiers transported far from their country. Lind compares men who have left the land of their birth to vegetables transplanted into a strange soil; they cannot experience the new conditions in which they are placed, without injury to their health or a loss of vigor, at least for a time. The masses of men which are transported far from their country, the European troops which go to another continent, are often smitten by more or less severe disease, evidently owing to this cause ; for these diseases not being known in the country where the men were born, they would have escaped them if they had remained there; of such is the yellow fever which destroys Europeans in some parts of America, and which has never been observed in the north of Europe, above the mouth of the Gironde; and abscess of the liver, so rare among us and so common in some parts of India. An almost constant fact, to which the attention of physicians has not, perhaps, been sufficiently directed, is the good health on board fleets which traverse the seas without making any port, and which is singularly in contrast with the diseases that afflict them under opposite circumstances. The constant change of place seems useful to man upon the ocean, as well as on land; voyages generally preserve and strengthen the health; if pas- sengers become diseased, it is almost always when they have been stationary for a certain time in the same place. The changes brought about in certain situations through the agency of man, as the clearing of forests, or the cutting of canals, have sometimes produced a marked effect upon the sanatory con- dition of the population. There are still some predisposing causes of disease, which may act simultaneously upon a great number of individuals, and which at present we shall only mention, because they act most com- 36 ETIOLOGY. monly upon isolated individuals, and thus appertain more naturally to the individual predisposing causes. Such are clothing, food and the moral affections. Wet garments suffered to remain upon the body, are one of the chief causes of rheumatism and dysentery in land armies, and of scurvy on board ship. If it surprise us that a cause, to all appear- ance the same, should produce different effects on land, and at sea, the reason of this difference may be discovered in the opposite qualities of rain and sea-water, the latter of which contains deli- quescent salts, which prevent the complete drying of the sailor's garments and keep him constantly wet. Food which has become putrid, salted meat, want of flour, or of fresh vegetables, and bad water, are all general causes of disease for the inhabitants of a besieged city, or for men in large num- bers on board a fleet or in camp. The moral affections, which are the same for the whole of an army, and sometimes for all the inhabitants of a city, or an empire, may be considered in some cases general predisposing causes. The influence of these affections upon the health of our soldiers, in the disastrous campaigns of 1813 and 1814, was very evident; the number of diseases increased in a frightful degree, as fortune for- sook our banners. Political institutions, and the more or less advanced state of civilization of different nations, must also be ranked in the number of the general predisposing causes of many diseases; it is for this reason that in free countries, among enlightened people, where the intellectual faculties are most active, where man de- votes himself to the study of the sciences and arts, to commercial speculations and to labor, and among nations often distracted by violent political commotions, mental alienation and hypochondria- sis are far more frequent than where the people live in idleness, ignorance or slavery. SECTION SECOND. Individual Predisposing Causes. Individual predisposing causes are much more numerous than those termed general, because there are many circumstances which may act upon isolated individuals and cannot be common to a great number; while all the general predisposing causes, as situation, dwelling, etc., are also individual predisposing causes. These causes being very numerous, and their influence in pro- ducing disease not being the same, we shall divide them into two series. In the first, will be classed the various conditions peculiar to each individual, as birth, age, sex, temperament, constitution habits, profession, degree of comfort or privation, illness, conva- lescence, health, and pregnancy; and we shall designate these ETIOLOGY. 37 different conditions by the term aptitudes, since they dispose the individuals to various diseases, rather than take an active part in their production. In the second series will be enumerated those various external circumstances, which predispose with more or less energy to the development of disease. I. Aptitudes. A. A descent from parents affected with certain diseases, is a condition which should lead us to fear the development of similar affections. " The ailments of our parents," said Baillou, " are inherited as well as their goods, and this sad inheritance is far more certainly transmitted than the other." Diseases which thus pass from father to child, are called hereditary; sometimes, so to speak, they skip one generation and manifest themselves in the grandchildren. They may appear in every child; but usually, only in a limited number. They may be transmitted by either father or mother. Cullen has observed that children are most subject to the diseases of the parent whom they most resemble. The diseases of the mother are perhaps more commonly trans- mitted than those of the father, not only because there is certainty in regard to the maternity, but also because the female, whose part in the act of conception is equal to that of the male, supplies from herself alone, what is required for the development of the foetus during its entire intra-uterine existence, and also nourishes it from her own substance through the whole period of nursing. It is, therefore, natural to suppose that the mother has a greater influence than the father upon the child's constitution, and upon its predisposition to disease. In support of this opinion, let it be remembered that in the crossing of animals, the relative influence of the two sexes is quite manifest: the mule, which is the issue of the mare and the ass, is incomparably larger and stronger than the product of an opposite cross. There is no longer any dispute in regard to the transmission of diseases from parents to children, considered in an abstract manner: but admitting this first point, discussions arise with regard to the question of the hereditary nature of particular diseases. There could be no doubt on this point, if the affections were such as show themselves only in the offspring of those who had suffered by them, and if all the children of parents so affected were attacked without exception; but this is not the case. On the one hand, every disease susceptible of transmission from parents to children may occur from other causes, and on the other, there is no cause which uniformly affects all the children who become diseased; it is only by aid of exact and numerous observations, which sci- ence does not yet possess, and which it can only slowly acquire, that we shall be able to appreciate the relative frequency of a dis- ease in individuals born of affected parents, and in those whose 4 38 ETIOLOGY. parents have been exempt from it, and thus determine how far a disease is hereditary. When we wish thus to study any disease, phthisis, for in- stance, we must seek the solution of the problem more by follow- ing the course of the children's lives, who are born of parents destroyed by this disease, than by going back to the complaints of which the parents died. It is, indeed, needless to examine whether the disease may be developed or not by the aid of hereditary predisposition and occasional causes. This is not the question: no author has asserted that a disease susceptible of transmission from father to child could not be developed likewise by other causes. The real question is, to determine at first, if such a disease is transmitted from parents to children, and afterwards, how frequently this happens. It is then, by following the gener- ations, rather than by tracing them back, (if we may be allowed the expression,) that the question of hereditary disease must be studied and definitely decided. We are convinced that by follow- ing this course in regard to pulmonary phthisis, results will be obtained, proving that children born of phthisical parents, die, in a great proportion of cases, of the same disease. It is not so easy to say what would be the result of similar research with the intention of ascertaining whether cancer is hereditary. In the present state of science, it appears to us reasonable to allow, without however affirming it, that individuals born of cancerous parents, are, other things being equal, more often affected with like complaints than those who are not thus connected. In general, diseases which are developed under the influence of hereditary predisposition, are manifested at an earlier age than when not thus transmitted. It has been remarked, that children born of consumptive parents, died at a less advanced age than their parents, and often before they were old enough to transmit this unfortunate predisposition. Reputed hereditary affections are exceedingly various. Some consist in an evidently vicious conformation, for instance, a diminution or increase in the number of organs; others, in simple functional disturbance without any appreciable lesion of the tissues, as blindness or deafness. Some are congenital, as is occasionally the case with syphilis, etc.; others, and by far the greater number, are latent for a longer or shorter time after birth; rachitis until the second or third year; scrofula and epilepsy appear in infancy; pulmonary consumption and mental alienation in youth; gout and haemorrhoids in adult age; apoplexy still later. In some families hereditary disease is developed and ter- minated, uniformly at the same period of life. Montaigne, whose ancestors were affected with gravel, was attacked by it at the same age as his father. Some practitioners have thought that chronic affections only, could be transmitted from parents to chil- dren; and it should be remembered that phthisis, mania and epilepsy occupy the first rank among hereditary diseases. Gout and rheumatism, however, are usually, acute diseases, at any rate ETIOLOGY. 39 in their first attacks, and by common consent, are hereditary. In some families it has also been observed that there exists a tendency to plethora and to certain inflammations. The diseases which infants exhibit at birth, {maladies de naissance,) are not always hereditary; those affected with hydro- cephalus or spina bifida, die soon; they cannot, consequently, transmit these diseases, and for the same reason they cannot have inherited them. Still farther, it has been remarked in certain cases, that all the children, or most of them, have been attacked by disease with which their parents never had been or could be affected; among other instances is sterility, noticed in all the daughters born of the same parents. Squamous disease of the skin and scrofula appear sometimes in all the children born of the same 'parents, although they may never have had those diseases. We must then, with Portal, admit family diseases, which although never observed in father or mother, but declaring themselves in all their children, are evidently ascribable to the influence exercised in generation by the concurrence of two determinate organizations, which give rise to one differing from each of the others, the same thing happening in all the offspring of such connection. We shall not give a detailed account of the different theories which relate to the hereditary transmission of disease. Like ex- ternal characteristics, this transmission is a well marked phenom- enon, but quite as inexplicable. The various hypotheses on this subject may be seen in the little work of Meara. * The Consider- ations of Portal upon hereditary and family diseases will be read with much greater interest by those who prefer facts to explana- tions : in this work the learned author has collected all that is useful and curious upon this point in pathology, j- B. Age. This is not, properly speaking, a morbific cause. No period of life plays an active part in the production of disease, but there is greater liability to certain affections at some ages than at others. Some complaints never appear previous to or after a certain period; on this account, those aptitudes for contracting disease which belong to the different ages, possess a peculiar interest for the student. Many affections may be developed at all periods of our existence, from intra-uterine life to the most advanced age. Children have been born with intermittent fever and with variolic eruption, both of which may occur at any other age. There are, however, diseases peculiar to every age, or at any rate of more frequent occurrence during such periods. Hydrocephalus and spina bifida are developed while the foetus is yet in utero. The diseases most frequently noticed at birth are the asphyxia of the new-born, * Pathologia hereditaria generalis, sive de morbis hereditariis tradatus, spa- gyricodogmaticus.— (Authore, Derm. Meara; Dublin 1619.) f Considerations sur la Nature et le Traitement des Maladies de Famille et des Maladies hereditaires, par Antoine Portal. 1814. Paris. 40 ETIOLOGY. icterus and hardening of the cellular tissue. From the first to the seventh year, the child is chiefly exposed to the eruptive fevers, to the accidents of dentition, epistaxis, croup, whooping- cough, tinea, rachitis, scrofulous complaints, acute hydrocephalus, tubercular meningitis and verminous affections. The period of puberty in females is fraught with various diseases. In both sexes, rapidity of growth sometimes disposes the system to serious affections. Plethora, inflammatory disease, haemoptysis, angina and pulmonary consumption are more frequent in youth than at any other age. In middle life, hypochondriasis, haemor- rhoids, cancer and the greater portion of organic diseases occur, scrofula excepted. In old age, softening and haemorrhage of the brain, idiocy, deafness, cataract, affections of the urinary passages, etc., are more common than in earlier life. The etiological study of the different ages offers still another consideration, viz. the inaptitude of certain ages for developing certain diseases. Thus cerebral haemorrhage is hardly ever ob- served before middle life; nor scirrhus and arterial aneurism previous to the thirtieth year; typhoid fever has perhaps never been observed after the age of fifty-five. These data are occasion- ally very useful in diagnosis. C. The ancients supposed there were certain fixed years in human life, when diseases were more frequently developed and attended with greater mortality. They called them climacteric years, from the word xVuia, tendency, or from *;.(>«£, signifying a scale or degrees. They compared these years to knots, which might be said to unite the different periods of life, and to give a new direction to the economy. This doctrine, which is said to have been derived by Pythagoras from the Chaldean institutions, was for a long time in great favor in the schools. Nearly all who have ad- mitted the climacteric years, have fixed them at intervals of seven years; they asserted the fourteenth and twenty-first years to be replete with danger. Others have divided them into periods of nine years. Some mingled the two, and the sixty-third year, composed of the numbers seven and nine, was, in their estimation, the most fruitful in diseases, especially those of fatal termination. Others preferred a triennial interval. All of them supposed that the space of time they thus allotted, was requisite for the complete renovation of the constituent elements of the body; so that at the end of three, seven and nine years, there did not remain in the system any of those parts which previously composed it; and, admitting this entire change in the constitution, an analogous change in the health seemed to them the almost unavoidable consequence. It is very certain, that in an indefinite time, varying according to age and many other circumstances, the body is renewed, and that hardly any of its former constituent parts are then found in it • but this change is not a sudden one: it is continuous, and modifies unceasingly the component parts of the body. It is no more per- ceptible at the seventh or ninth year, than upon every day which ETIOLOGY. 41 goes to make up the climacteric periods. These useless specula- tions have, with great reason, been rejected; they seem fitted merely to torment the imagination of the sick. * D. The sexes are nearly alike in their predisposition to most diseases: fevers, inflammations, nervous and organic affections, attack males and females without distinction. If there be any difference between their diseases, it is rather to be attributed to the mode of life, than to sex. If the male be more subject to wounds, contusions, fractures, rheumatic affections and typhus, it is because he is more exposed to the causes of such affections. In like manner, in cities, women are more subject to nervous diseases than men. But in the opposite case; if we compare the female who labors in the fields, to the man who leads a luxurious and inactive life in the city, the former will be observed to be liable to the same complaints as the man whose occupations are similar, and the latter to all those nervous affections which have been con- sidered as peculiar to females. There are, indeed, certain diseases which attack one or other of the sexes most frequently; of these, tuberculous disease of the lungs is more common in females than males; and that this difference is observable in every period of life, any one may be convinced by consulting the statistics of M. M. Louis, Benoiston de Chateauneuf and Papavoine. There are certain diseases which almost exclusively belong to sex: not to mention those of the genital organs and their appen- dages, as hydrocele and sarcocele in man, scirrhus and inflamma- tion of the uterus and ovaries in the female, stone in the bladder and retention of urine are almost exclusively confined to the male sex, while crural hernia, hysteria and mammary cancer are pecu- liar to women. E. Temperament predisposes to various affections, and gives a peculiar character to any that may be developed. In the san- guine temperament, there is a tendency to plethora, to deep-seated inflammation, haemorrhages, etc.; and almost all the acute dis- eases occurring in persons thus constituted, are accompanied with general symptoms of inflammatory fever. The bilious tem- perament is conducive of bilious diarrhoea, the exanthemata, inflammations of the membranes and organic disease, especially cancerous degeneration. Those of a lymphatic temperament are peculiarly liable to catarrh, chronic discharges, dropsy, scrofula, and scurvy; and nearly all the acute diseases which affect them are of an adynamic character, and slow in their progress. Those of a nervous temperament are particularly subject to hysteria, hypochon- * Some authors have given a different signification to the vi or A climacteric: they understand by it the periods of life at which great changes occur, indepen- dently of the numerical order of the years ; such is the epoch of puberty in both sexes and the suspension of the menstrual discharge, or critical season, in females. Every one allows the influence of these climacteric epocJis upon the constitution and health. 4# 42 ETIOLOGY. driasis, convulsions, disturbance of the sensations and intellectual faculties, melancholy, mania, etc.; and in addition to the ordinary symptoms of acute disease, various disorders of innervation, which alter the character of the affection, make its course irregular and its termination less certain. The mixed temperaments predispose, though less energetically, to the affections peculiar to each of the temperaments united in the same individual. F. A very strong constitution seems rather a preservative against all disease than a predisposant to any. Nevertheless, it has been observed that such constitutions are more subject than others to acute and violent inflammatory affections. Those of feeble constitution, on the contrary, are liable to frequent and slight attacks of disease, and to habitual indisposition, and nearly all of them die of chronic disease. It has also been remarked, but with- out sufficiently accurate data, that very corpulent persons are subject to apoplexy, and are almost entirely exempt from inflam- mations of the thoracic organs. * The disposition of each part of the body seems also to have an influence in hastening the development of disease. Considerable volume of the head should lead us to apprehend hydrocephalus in children and apoplexy in the aged. A remarkably broad chest excites suspicion that the contained organs have a size dispropor- tioned to that of the other viscera, and this disposition is like the first stage of cardiac aneurism. Those in whom all the cavities are large, or to use the expression of Hippocrates, who have volumi- nous viscera, are, according to this prince of medicine, liable to arthritis. The weakness of the aponeuroses which correspond to the natural apertures of the abdomen, is the chief predisposing cause of hernia. The structure of the bones in children, favors the detachment of their epiphyses and their abnormal curvature ; in the adult, the angles which the neck of the femur forms with its supporting bone, and the ramus of the lower jaw with its body, favor the fracture of the one and the dislocation of the other. Finally, in the aged subject, the diminished thickness of the compact part of the bones, the predominance of their inorganic element, and the increased size of the medullary cavity of the long bones, are each circumstances explanatory of the frequency of fracture in old age. G. Habits, which arise from the frequent repetition of the same acts in a given time, are usually injurious to those who become enslaved by them, and they are very properly numbered among * Obesa corpora minus pleuritidi el peripneumonia; sunt obnoxia, ut animad- vertit aeque diligens ac erudilus medicus Trillerus. Quod cum omnes peripneu- momcos a me visos aut curatos memoria repeto, verum esse intelligo ; et ipse poteris, perlectis eorum qui a Valsalva itemque & me dissecti fuerunt historiis cunctis, duobus exceplis, facile cognoscere. (Morgagni de Sed. et Caus. morb., Epist. XX. art. 10.) ETIOLOGY. 43 the predisposing causes of disease. The power of habit and the danger of its discontinuance are in proportion to its duration and the number of actions committed under its influence in a given time. So great is this power that, as Cabanis has remarked, it would be dangerous to change from the worst regimen to the wisest and best. Now as there is no habit which we can be sure of satisfying through life, it is prudent not be bound by any, unless absolutely compelled. Many habits are injurious to the health from the moment they are contracted; all may become so if interrupted. H. The professions may predispose to different diseases, by the concurrence of circumstances in which those practising them are placed. Literary men are subject to headaches, wakefulness, and haemorrhoids; many die of apoplexy. Faggot-bearers are subject to hernia; watermen, to a peculiar alteration of the dermis, charac- terized by softening, fissures, and frequently absorption of the parts in contact with the water; * while, contrary to the common opin- ion, they are rarely affected with ulcers of the legs; f varicocele is of frequent occurrence in horsemen. I. Statistics collected by numerous distinguished physicians, demonstrate satisfactorily the sad influence of poverty upon mor- tality. Dr. Villerme has proved by very interesting researches, that in Paris and many other large cities, the proportion of deaths to the number of inhabitants in the different quarters, is in an inverse ratio to their degree of comfort. % M. Benoiston of Cha- teauneuf has arrived at similar conclusions; he has observed that, at the same periods of life, the mortality among the poor is almost double that of the rich. |j The diseases most usually observed * under these circumstances among the poor are scurvy, scrofula, tinea and some other exanthematous diseases; in the higher classes, inflammatory and nervous diseases are most frequent. It nevertheless sometimes happens that similar affections, not contagious, such as catarrh and erysipelas, prevail simultaneously in both classes. J. The state of health, of convalescence or of disease, has like- wise an influence upon the facility of development of various affections. It would be absurd to rank health among the preparatory causes of disease. There are, however, certain affections which are observed only in those who previously enjoyed perfect health; such is the ephemeral fever produced by an evident external cause; * This affection, peculiar to the skin, has received the name, grenouilles. See the Memoir of Parent-Duchatelet upon porters employed to unload boats. — An- nates de hyg. publ. t. iii. p. 245. f Of 670 boat porters examined by Parent-Duchatelet, one only had an ulcer. \Annal. d'hyg. et de mid leg. t. iii. p. 294. || Annal. d'hyg. et de mid. Ug. t. iii. p. 5. 44 ETIOLOGY. the same cause would have excited in another person a more serious malady, etc. Descriptions of epidemics also exist, in which the prevailing disease attacked healthy individuals by preference, as it were, while feeble and infirm persons escaped. But the opposite of this has been almost constantly observed, and a dis- eased condition must always be considered as favorable to the development of prevailing complaints, and as a predisposing cause of various affections. Dlemerbroeck states, that in the plague of Nimegue, all those who were attacked by any complaint whatever, were soon afterwards affected with the contagious malady; the same was remarked in the epidemic cholera of Paris in 1832, and has been noticed in many other epidemics. Oedema of the glottis scarcely ever occurs except among patients already seriously ill. Convalescence is accompanied by a debility and susceptibility, which greatly accelerate the action of morbific causes. K. Pregnancy, likewise, renders the system liable to different diseases. Many women experience some nervous affection during gestation, as vomiting, depraved appetite, cramp and convulsive movements; or plethoric accidents, as headache, ringing of the ears, oppression, or palpitations, which yield to venesection, etc.; during the period immediately succeeding delivery, the suscepti- bility of women to attacks of acute disease, to which the epithet puerperal is given, is singularly augmented; every one knows how frequent these affections are; the uterus with its appendages is most usually the origin of disease; acute metritis supervenes more often under these circumstances, than in any others. The same is true in inflammation of the mammae during lactation. Nursing women, and those who have lately weaned their children, -* are very easily affected by the action of the productive causes of rheumatism: they often experience its attacks, and it then receives the popular name of milk pains. 2. Individual predisposing Causes, properly so called. Having pointed out the various conditions which we have styled aptitudes, and which may predispose to disease, we shall briefly examine the individual predisposing causes, properly so called, which belong to the second series. A. General causes prevail in the class of the circumfusa ; still there. are some that act upon isolated individuals, as the fre- quenting of dissection rooms and hospitals, which disposes to dis- ease of an adynamic character ; also an habitual residence in con- fined, ill-aired, and overheated apartments, which renders the body more sensible to external cold, and more likely to be affected by it. Change of climate, which is a general predisposing cause for troops transported to the colonies, is more frequently an individual ETIOLOGY. 45 predisposing cause. The inhabitants of the country when they come to reside in cities, almost always experience some disorder ; within the first few days, diarrhoea, or severe fever after some months' residence. The greater number of those who retire to the country, after having spent the first part of their lives in cities, as for instance, merchants who have become independent, or pub- lic functionaries who have lost their situations through political vicissitudes, soon experience more or less disturbance of health, which often results in death. But we should observe, that, in all such cases, many other alterations assist the mere change of dwell- ing-place in causing the result thus observed. B. Some individual predisposing causes are found among the applicata. Clothing, when too thin, favors the action of causes productive of catarrh and rheumatism. That which is too warm, determines indirectly a similar effect by increasing the susceptibility. The form of the dress, which changes according to the fashion and tastes of the various classes of society, is not without its influence upon the health. Many physicians think that the costume adopted since the French Revolution, has con- tributed very much to render pulmonary consumption more com- mon among females, and croup among children; the exposure of the neck, the arms, and the upper part of the chest, accounts apparently for the frequency of these diseases. It has been said also, that the Greeks and Romans, whose legs were habitually bare, were more subject than we are, to erysipelas of those parts. Among the morbific agents belonging to the applicata, those acting through the medium of compression probably produce the most remarkable effects. The immediate effect of all compression is to diminish the vol- ume of the parts subjected to it, and almost constantly to inter- fere with the action of the organs, to retard the circulation of the fluids, and particularly of the venous, and even the arterial blood. In this case, compression may have a rapid and manifest effect, like the specific causes; the gangrene which occurs in a tumor, whose base is surrounded by a ligature, and asphyxia caused by compression upon the trachea, are examples; but in the great proportion of cases, the effects of compression manifest themselves slowly, like those resulting from the action of predis- posing causes. These effects, which are exceedingly various, might belong to either predisposing or determining causes; still we have included them under one head, so as not to separate them from those phe- nomena which are more interesting when studied collectively; they depend on the nature of the compressing agents, the struc- ture of the parts compressed, the time during which the compres- sion is continued, the extent of surface compressed, and the force with which it is applied. 1. The agents capable of producing compression are very nu- merous : some are applied to the surface of the body, as the cloth- 46 ETIOLOGY. ing, particularly corsets, garters, and girdles; others, whose action is internal, are either foreign bodies or morbid growths, as tumors, effused liquids or gases, which become an actual cause of various secondary disorders by means of the compression they maintain upon the neighboring organs. The elastic corsets used by most females, are, probably, one of the causes which lead to the development of organic disease of the lungs and heart, particularly during the period of growth and that of pregnancy, when the chest should rather be increased in volume. In this latter case, there are many other inconveniences : the pressure upon the abdomen prevents the development of the uterus, tends to give it an abnormal position, and may excite abortion. Their action upon the mammae is not less marked : it prevents their attaining J;ne increased volume which they should acquire, flattens the nip'ple, and renders nursing difficult or im- possible. The stomach and intestines thus compressed, some- times assume a faulty position, the exercise of their functions is always impaired; the inconvenient and noisy borborygmi, so frequent in females, are probably owing to the compression of the intestines by corsets; this is scarcely ever observed in men. Compression, however slight, if long continued, caused by sur- gical apparatus, or by a simple bandage intended to support the dressing of an issue, may sensibly diminish the volume of the part compressed, and sometimes may occasion oedema of that por- tion of the limb in which the venous circulation is obstructed. Garters, when very tightly drawn, may cause varicose dilatation of the veins. Very narrow socks worn in childhood, change the conformation of the toes, and at any age produce a thickening of the skin and the development of those hard and painful tumors called corns ; but friction contributes to this result. The synovial cyst called hygroma, which is formed in the neighborhood of the*. knee and elbow, in workmen whose employment forces them to ! press continually upon these parts, either with the instrument they use or against the table at which they work, is an analogous for- mation. Compression of the neck, by a tight cravat, excites or increases the distension of the cerebral vessels, and favors haemorrhage and inflammations of the brain. Internal compression, caused by a tumor, affects the organs in various ways. It attracts but little notice when the tumor is be- neath the skin or between the muscles, because the resistance is slight and the compression consequently less. The case is nearly the same when the tumor occupies the superficial portion of the abdomen, whose anterior parietes are susceptible of considerable extension. But it is otherwise within the skull, the thorax, the nasal fossae, and even the inferior parietes of the mouth. The primary effect of tumors developed within the skull is to compress the corresponding cerebral hemisphere, and to induce more or less complete paralysis of the muscles of the opposite side. If the tumor be near the bony arch of the skull it often hap- pens that it gradually reduces the thickness of the bone, even to ETIOLOGY. 47 the tenuity of parchment, and in some cases completely perforates it, making its appearance through the aperture; fungous tumors of the dura mater often present this series of phenomena. Analo- gous effects occur in the chest: such as functional disturbance, and absorption of the parietes. If the tumor be in the vicinity of one of the axillary regions, it sometimes causes, by compression of the artery, a progressive decrease in the force of the pulse upon that side, and by compression of the veins and lymphatics, oedema of the corresponding limb. If the compressing agent be a fluid, its effect is only distension of the natural or adventitious cavity which encloses it, and inter- ference with the action of neighboring organs, as is uniformly noticed in the abdomen, often in the thorax, and occasionally in the skull, where ossification is incomplete; but absorption of the bony walls never occurs, as it does from solid tumors. 2. The structure of compressed parts has great influence upon the phenomena of compression. This may be easily appreciated in the chest, where the organs differ very much from each other in texture, and whose parietes are composed of both hard and soft parts. It is observed that the softer and more flexible the tissues, the less change occurs in their texture, in consequence of the tumors which compress them ; on«the other hand, the harder they are, the greater effect is produced. Thus an aneurismal tu- mor of the arch of the aorta causes absorption of the sternum, cartilages of the ribs in front, and of the vertebrae behind, while, for a long time, it simply displaces the heart, and diminishes the volume of the lungs. If the trachea be compressed, the cartilaginous rings are first de- stroyed ; their uniting membrane resists for a long time, as do the intercostal muscles when the ribs and their cartilages are already ^^diabsorbed. In the case where the tumor opens into the bronchial * tubes, the oesophagus, pleurae or pericardium, and causes death, the comparative examination of the different parts shows that the lesion of those which are hard and resistant is greater and of earlier date than that of the soft parts. We should notice that there is here something special in the nature of the compression, on ac- count of the pulsation occurring in aneurismal tumors; both per- cussion and compression exist. The application of this principle and the proof of its truth is found in the tumor known as ranula, which causes absorption and deformity of the lower maxillary bone and of the teeth therein inserted, and only occasions simple displacement of the soft parts. But in all these cases the latter resist only by reason of their elasticity under the force of the compressing agent. If compression be so applied as that they cannot thus escape it, they feel its effects, and indeed much sooner than the firmer tissues; as is observed by the formation of eschars on those portions of integument compressed between super- ficial and projecting bones, as the sacrum, the great trochanters, and the bed on which the patient lies. 3. The effect of compression is proportionate in great measure to 48 ETIOLOGY. the time during which it is exercised. When short, even though very violent, provided it be not carried far enough to cause altera- tion in the tissue of the organs, the latter immediately regain their size and the full exercise of their functions. After longer com- pression, for some days, or weeks, for instance, the natural condi- tion is slowly, but maybe completely regained. It is far otherwise when compression has been continued for a considerable time, as for years; it then most usually happens that the suffering organ does not regain its primitive volume ; this is particularly the case with the lungs after pleuritic effusions. There is, moreover, this difference between compression of short and long duration, that in the former, the diminution in volume seems alone owing to the liquid contents being discharged and the solid parts brought more closely together, while in the latter there is a real decrease in the solids themselves, partial emaciation or atrophy. 4. The extent of surface over which compression is applied, also modifies its effects. A very narrow bandage may penetrate the tissues; a broader one would not. When compression is main- tained upon one particular portion of a limb, the circulation be- comes arrested below the point of application. This does not happen if the compression extend to the extremity of the limb. Such are the chief effects of compression in the development of disease either primitive or secondary, whatever be the agent or the recipient organ. Beds also deserve some attention. The habit of sleeping upon feathers, by increasing cutaneous transpiration, favors the forma- tion of urinary calculi and disposes to nephritis. A hard bed does not seem a predisposing cause of any complaint. Seats, which are very soft, and particularly those furnished with feather cush- ions {bergeres), are conducive of sanguineous congestion in the uterine and haemorrhoidal vessels. The daily use of cold baths is thought to predispose to inflamma- tory disease by their tonic action upon most of the organs. Warm baths, often repeated, produce an opposite effect; they weaken the constitution, and predispose to chronic discharges and diseases of debility. Want of cleanliness generally favors the development of all contagious and cutaneous diseases. Excess of cleanliness, combined with the use of perfumes and the various resorts of lux- ury, seems to aid in the production of nervous diseases. C. Ingesta. Food, liquids and remedies may dispose to various diseases when improper use is made of them. In health, the quantity of food and liquid should vary according to age, strength, occupation, habits, etc. Their moderate and temporary increase or diminution does not usually produce func- tional disturbance, but beyond certain limits the health becomes deranged. A decided and long continued diminution in the ordinary quan- tity of food causes analogous loss of strength and flesh • its increase produces plethora. Habitual excess in food seems to dispose to ETIOLOGY. 49 organic disease of the stomach and intestines, which is not always avoided by extreme abstinence. The daily abuse of fer- mented liquors, of wine or alcoholic drinks, gives to acute diseases so grave a character as to render them generally fatal. Wine and alcoholic liquors are more pernicious in their effects when drunk between meals than when taken into the stomach mixed with solid food. The disease known as delirium tremens is often owing to the abuse of these drinks, or to their sudden ab- straction from the intemperate.* According to some physicians, sudden death and spontaneous combustion are not rare in persons who use habitually a large quantity of alcohol. The immoderate use of coffee disposes to cerebral congestion and inflammation of the stomach ; tea, on the contrary, weakens this viscus gradually, and seems to predispose to chronic discharges. Some authors have attributed the frequent occurrence of leucorrhea in women re- siding in cities to this cause, and others have seen the use of beer produce blennorrhagia in both sexes. It has been said that the use of cider and beer in England and Normandy, is the chief cause of the rheumatism so common in those countries; but is not this rather to be attributed to the conditions which prevent the cul- tivation of the vine, and to the moisture of the soil ? The bad quality of food containing in itself but little nutriment, or altered by putrefaction, fermentation or mouldiness, disposes to disease of more or less severity, as inflammations of the diges- tive canal, adynamic fevers, scurvy, etc. The use of bad water, like that drunk on shipboard during long voyages, of sour wine, or badly prepared cider, produces analogous effects. Variety in food is necessary to man. The satiety experienced after having for a long time used the same alimentary substances and the satisfaction experienced by a change, prove the truth of this assertion. The exclusive use of any one article of food, in those whose unrestrained habits would have been opposed to such a course, almost always terminates in disease ; farinaceous food dis- poses to plethora, fat and oily articles induce chronic discharges, and animal substances give rise to inflammatory complaints of every description; salted food, in conjunction with want of vegeta- bles and the fruits of the season, produces scurvy; the prolonged use of a scanty regimen is a frequent cause of obstinate constipa- tion and various digestive troubles, in those who fast throughout Lent. Spices and powerful condiments, as pepper, mustard, pimento, etc.. increase, at first, the energy of the stomach ; but this viscus becomes accustomed to the action of such excitants, which soon cease to stimulate it, and inactivity frequently succeeds the temporary ex- citement. The abuse of these substances may cause inflammation of a part or the whole of the digestive canal, of the mouth, the pharynx, stomach and intestines. Medicines, considered by most persons as means of preserving * Buke, Edinb. Med. and Surg. Jour., t. xix. 5 50 ETIOLOGY. and re-establishing the health, may sometimes disturb it. Reme- dies styled precautionary, far from strengthening, often injure the health. Repeated emetics have finally caused weakness or even inflammation of the stomach, and purgatives thus used have had the same effect on the bowels. The use of medicine not indicated in the course of a disease, may instantly cause a new affection or aggravate the existing complaint. D. Excreta. The evacuations may vary considerably without derangement of the health ; usually, one being augmented, another is diminished, so that the balance of the system is preserved. Slight changes in the quantity of the evacuated matters, either more or less, do not suffice for the production of disease ; but when the disproportion between the excreted matter and the reparatory means becomes very considerable, it acts upon the constitution and so modifies it, as to predispose it to various affections. If the quan- tity of food daily assimilated be greater than the portion excreted, a tendency to plethora and inflammations of every kind is the con- sequence ; if, on the contrary, absorption is not sufficient for the reparation of the daily losses of the economy, the body gradually diminishes and is liable to complaints resulting from debility. Profuse sweating, copious salivation, too great secretion of milk in nurses, etc., cause the latter effect. In man, venereal excess and masturbation act in a similar manner, with this peculiarity, that nervous phenomena almost always accompany the debility arising from repeated evacuations of semen. The debility induced by excessive evacuations, brings into ac- tion the occasional and determining causes of disease. Thus a man who, during his whole life, has exposed himself with impu- nity to the inclemencies of weather, is attacked with rheumatism, when exposed after excess in venereal indulgence.* The same circumstance disposes to attacks of yellow fever at St. Domingo ;f and Diemerbroeck % observed at Nimegue, that all who married during the continuance of the plague, were attacked by the con- tagion a few days after their nuptials. Abundant haemorrhage, bleeding, and repeated purgatives, have had the same effect during many other epidemics. Natural or artificial evacuations, when reproduced at nearly equal intervals, have a very different effect, especially when they are confined within certain limits; the system repairs and sup- ports these losses, either by the diminution of other evacuations, or by the assimilation of a greater proportion of food; from thisj plethora results. Periodical evacuations, natural or artificial, cause this to yield, but at the same time they increase the tendency to its reproduction, so that nothing more strongly predisposes to ple- thora, or at any rate, to strengthen the predisposition to it when * Essai sur la Rhvmatisme, 1813. f Traiti.de la Fievre javne, par Bally. % Diemerbroeck, de la Peste de Nimkgue. ETIOLOGY. 51 existing, than these evacuations. The menstrual discharge in females, periodical haemorrhoids in males, and habitual bleeding in both sexes, often produce this effect. The suppression of habitual evacuations, the omission of cus- tomary bleeding and purging, may tend to produce various com- plaints ; but they act generally as occasional, rather than predis- posing causes. E. Gesta. The precise degree of action and rest, of sleep and waking, to which man should restrict himself in order to preserve his health, cannot be determined ; nevertheless there are certain bounds which he can rarely pass without deranging the harmony of the functions. Any marked disproportion between exercise and repose always injures the health ; too great fatigue induces a kind of debility, and gives an adynamic character to acute affections developed under such conditions. It has been said of country people, that usually they have but one disease in their lives, and that fatal to them. Partial exercise may also predispose to certain affections ; the con- tinual and repeated movements of the arms, for instance, seem calculated, in a greater degree than those of the lower limbs, to bring on haemoptysis in those subject to it, and to hasten the progress of cardiac aneurism. The want of exercise is far more replete with danger than the opposite extreme; this is more decidedly the case in proportion as the individual has need of exercise, on account of his age, habits, and strength. Thus it is most injurious to children, to robust per- sons, and to those who have always led an active life. It is ob- served that a sedentary life is less prejudicial to the female than to the male, either because, from youth, habit has lessened in her case the troubles arising from it, or because such a life is more conformable to her peculiar destination, and consequently to her constitution. Want of exercise is the source of many disorders. One of its first effects, is loss of appetite and slow digestion; dys- pepsia frequently recognizes this as its sole cause, and yields only to regular exercise. Prolonged inaction causes debility of the lo- comotive organs, favors sanguineous congestion towards certain parts, and vitiates nutrition; the body increases in size and loses strength; adipose polysarcia, mucous discharges, scrofula, and oedema, are the different results of this inaction when carried to a great extent, the effects varying according to the constitution of the individual. The same cause, in a less degree, exercise not being quite sufficient, disposes to plethora, especially in high livers. In- action of a single limb usually produces mere local effects, such as weakness, diminution of size, and atrophy of the part which is kept motionless. That change, which is necessary in all the acts of life, is espe- cially so in regard to the positions of the body. The restraint arising from too long retention of one position, the need of chang- ing it at intervals, even during sleep, had already established the 52 ETIOLOGY. truth of the above assertion, even prior to its adoption as a hygi- enic precept. The upright posture, when habitual, disposes to varicose affections, oedema, of the legs in both sexes, varicocele in man and prolapsus uteri in women ; the sitting posture, to haemor- rhoids and engorgement of the abdominal viscera; the kneeling pos- ture induces lumbago and early curvature of the spine ; horizontal posture favors cerebral congestion, epistaxis and apoplexy. This latter position, when maintained for many months, on account of fractures of the lower limbs, has often seemed to be the main cause of calculous formations in patients who had never previ- ously been so affected. A proper division of our sleeping and waking hours is useful in maintaining health. From six to eight hours' sleep are neces- sary for adults ; less is requisite for old persons, and more for chil- dren. But here, as elsewhere, general rules admit of exceptions; some persons need nine or ten hours' sleep; four or five are suf- ficient for others. Prolonged sleep induces general sluggishness, and predisposes to plethora and cerebral affections. Those who retire and rise very late, who sleep in the daytime and remain awake at night, hardly ever attain to an advanced age. After long watchings, nervous affections are frequently developed, and particularly great irritability of the nervous system. F. Percepta. The sensations, passions, and intellectual efforts, when they exceed certain limits, become predisposing causes of disease. Sensations, habitually very feeble, augment by degrees the sen- sibility of the organs which are their seat, to such extent that they become unfit to bear those which are moderately powerful: this is observed in individuals who remain for a long time in a dark abode, and among those who live upon very unstimulating food. Sensations habitually very lively, on the contrary, exhaust the sensibility of the organs, and render them unfit to fulfil their func- tions. The passions have a very remarkable influence upon the de- velopment of disease. While the mild and varied, favor the har- mony of the functions, the strong and exclusive, are injurious in the same degree. They not only may affect the system in a sud- den and marked manner, as in the instances of derangement, instant death and hectic fever from moral causes, as we have seen in the enumeration of determining causes ; but they also, and far more frequently, give rise to an exaggerated sensibility which peculiarly predisposes to nervous affections. Prolonged grief seems to have a powerful influence in developing organic diseases es- pecially cancer. Mental labor, when excessive, predisposes to nervous affections • but it does not hence follow, as has been supposed, that study is contrary to nature. It is a law of nature, that the greatest pos- sible intellectual and physical development should be simultane- ously attained. The exercise of the mind, meditation and study ETIOLOGY 53 are necessary to the development of the intellect, as motion is to that of the body. When the object of study suits the taste of the student, when it alternates with some manual occupation or with suitable exercise, it rather benefits than injures the health. Many literary men, physicians and mathematicians, have attained to very advanced age; and if there have been those who have died from excessive application, the number is very small. When, however, studies are continued daily for many hours, and relate to subjects in themselves uninteresting and irksome to the one employed in them, when they are not varied and interrupted from time to time by exercise, the body is injured in its development; the energy of the mental powers may be blunted, and in early youth the germ of the most brilliant faculties blighted. Antecedent diseases may be added to these different individual predisposing causes; they strongly favor the action of those spe- cific or occasional causes which are likely to excite anew the above named diseases. A first attack of hysteria or rheumatism not only indicates the aptitude of the patient to be thus affected, but seems to increase the tendency to repeated attacks. It has often been noticed in ulterior attacks of hysteria and rheumatism, that very slight occasional causes sufficed for the development of these affections, while the first attack required the influence of very powerful agency. ARTICLE THIRD. Occasional or exciting Causes. Occasional causes, as we have stated, are those which excite disease without determining its nature or situation, and which act only with the concurrence of the predisposition. These have not the importance which attaches to those of the first two orders; but because they do not belong to the particular history of any one disease, they are, more than the others, within the domain of general pathology: their enumeration is therefore necessary. The impression made by very cold or very hot air, by the north or south wind; the action of a current of air upon the whole body, or of a smaller draught {vent coulis) upon one part in particular ; the sudden passing from a very warm to a very cold apartment, and vice versa ; a short stay in a damp house, newly built; a temporary change in the thickness or form of the gar- ments ; immersion in a very hot or very cold bath, exposure to rain; wet clothes retained upon the body; errors in diet, as the excessive ingestion of food, otherwise of good quality; the use of inferior or badly prepared food, difficult of digestion, taken at an unaccustomed hour or hastily eaten; very hot or very cold drinks, or those injurious by their quality; the suppression of 54 ETIOLOGY. certain natural evacuations, as the perspiration, lochia, milk, and menstrual discharge; or of a morbid or artificial discharge, as that of leucorrhea, chronic ulcers, long established setons or blisters; an habitual hasmorrhagic discharge which has become necessary ; a natural evacuation considerably increased ; untimely venesection ; emetics and purgatives administered without indica- tion ; excessive fatigue ; an unusual amount of rest; cries; singing; shouts of laughter; running against the wind; prolonged watch- ing ; physical or moral shocks; lively emotion, as joy or terror; necessary mental strife; retrocession of gout; disappearance of exanthematous affections; sudden cessation of some other com- plaint; such are the chief occasional causes of disease. These differ from special and predisposing causes by not being connected with the history of any affection in particular. One occasional cause may excite any disease, and the same disease may be induced by every kind of occasional cause. If there were any doubt as to the correctness of this proposition, the ex- amination of any treatise on pathology would suffice for its re- moval ; in the portion devoted to the etiology of each disease, the acute in particular, all the occasional causes we have just named would be almost literally enumerated. It is quite otherwise with the determining causes; they differ either in themselves or as re- gards the parts upon which their action is exerted in each kind of disease. Notwithstanding this great difference between them, there are many points of contact, where the occasional, are, as it were, mingled with the determining and predisposing causes. For instance, is cold a determining or an occasional cause of rheuma- tism 1 The different opinions of physicians prove that this is a point not easily decided. On the other hand, if we compare occasional and predisposing causes, it will be seen that the same circumstances may belong to each. There is, it is true, this differ- ence, that in the one case, the cause is momentary in its action, while in the other, that action has been of long duration; an error in diet is an occasional cause ; habitual intemperance, on the contrary, is predisposing; the distinction is very marked when our examples are extreme cases, but becomes more obscure in proportion as they are less so; excesses which are prolonged for many days, for one or several weeks, can hardly be said to belong decidedly to either class. There are some circumstances where a simple error in diet, usually considered one of the occasional causes of disease, becomes a predisposing cause. During epidemic variola or prevailing plague, excessive drinking or venereal indul- gence often repeated in the space of a few hours, have frequently been observed to favor the action of the pestilential or variolic virus, and the individual who for months had braved contagion with impunity, has been attacked immediately after being debili- tated by these causes, which, in these cases, evidently acted as predisposants. This division of morbific causes presents some defects; nature does not submit herself to our divisions in this instance any more ETIOLOGY. 55 than in others; she cannot be rigorously bound by any. The proposed arrangement seems more methodical and practical than others; above all, it is particularly suitable as our guide in the study of morbific causes, considered in regard to their mode of action. ARTICLE FOURTH. Mode of Action of Morbific Causes. All the organs of the human body are not equally exposed to the action of morbific causes; the alimentary canal, the lungs and the skin are more apt to receive from them an injurious impres- sion on acccount of their more intimate relations with external objects. Hufeland in his Pathogeny* has for this reason denomi- nated them atria morborum, the gates of disease. To them should be added the brain and nerves, which especially in civilized man, are directly exposed to the action of a large class of morbific causes. Among the agents which disturb the health, there are those which, impelled by a greater or less force communicated to them, or by means of their chemical qualities, penetrate into the substance of the organs; their action is purely physical or chemical; their effects would be the same upon the dead body. Among these are bodies which cause wounds, caustic substances and fire. Others influence only the living tissues, and can act only by the power of vital laws. Such are acrid plants and rubefacients, whose action is confined to the skin and mucous membranes with which they are in immediate contact; food and drink, and perhaps poisons, and certain miasmata which penetrate the system through the ab- sorbent vessels, and whose morbific effects may be felt very far from the spot where they were first deposited ; the passions, sensa- tions and intellectual efforts which manifest themselves through the nervous system, are also of the same class. We shall not extend farther our remarks upon the mode of ad- mission of these causes into the system ; but will proceed to point out the modus operandi of the three classes of causes which we have proposed. § I. The action of specific causes is usually evident, although not always easy, and often impossible to explain. When a wounding instrument penetrates any part, fractures a bone, injures a tendon or an artery, we suppose the force which divided these organs to have been superior to that which preserved their continuity; we can likewise account for the disordered mo- tions, and the flow of blood which result from such injuries. A foreign body in the trachea or bladder causes symptoms easy of * IIu6og, disease ; yirofiai, to exist. 56 ETIOLOGY. explanation, because its action is wholly mechanical. The case is similar when the passage of alimentary matter is intercepted, where the intestines are compressed by a tumor, or strangulated by a peritoneal, or hernial stricture. We can understand likewise how a violent contraction of the muscles may cause hernia, dislo- cation, fracture of the patella, or rupture of a tendon ; but most of the causes we have enumerated, while they exert a mechanical action upon living organs, produce other effects subordinate to the vital laws. Thus, divided or displaced parts become red, hot, painful and swollen ; a new secretion is established in them, etc. There is nothing surprising to us in these phenomena, because we are accustomed to observe them. But if we desire to examine them thoroughly and to know the mechanism of their production, we are compelled to acknowledge our ignorance, unless we are willing to substitute error in its place, or veil it by language which imposes even upon ourselves. Notwithstanding the progress of modern chemistry, we are constrained to say the same thing in re- gard to the action of the gases which produce asphyxia. We know that some suspend gradually, and others immediately the phenomena of life; we are acquainted also with the changes' caused by some of these agents in the color and consistence of the blood; but asphyxia still remains unexplained. The action of the poisons upon the economy is equally well demonstrated, but quite as inexplicable. Why is a species of coma caused by the narcotic poisons ; inflammation of the stomach and intestines by the acrid, and gangrene of various parts by the septic ? These are questions which do not admit of reply. We can more easily understand the effects of fire and caustics, because they are partially the same upon all organized bodies; but their peculiar action is quite as much beyond our penetration. The action of contagious principles is yet more obscure. To a certain extent we are acquainted with the agents of which we have just spoken; we appreciate the physical and chemical properties of the irresplrable and the deleterious gases, caustics and some poi- sons. This is not the case with contagious principles, for they escape our senses, and those whose action is most easily appreciated, as vaccine and variolic virus, cannot be separated from the vehicle which contains them, and studied in regard to their properties. Thus it is only by a process of reasoning that we admit their ex- istence. Many authors have compared the development of contagious diseases to that of vegetables, and likened the contagious principles to their seeds. If we bear in mind what has previously been said of contagion, it will be easy to see the principal points of analogy between them; but the resemblance is far from complete. The existence of plants and the seeds from which they spring, is mani- fest and does not admit of doubt. The existence of contagious principles, on the contrary, is only admitted as a consequence of a series of facts which are thus clearly explained, and which other- wise would remain inexplicable. Certain diseases being capable ETIOLOGY. 57 of transmission from affected to healthy individuals, this mode of transmission has been called contagion, and the inappreciable agent is called a contagious principle. The action of contagious principles is obscure for many other reasons. Do they act directly upon the nerves of the part with which they are brought in contact, or are they absorbed into the rest of the system ? These two opinions have been supported by quite plausible arguments ; and each might be true as regards cer- tain poisons, for it is possible that all may not obey the same laws in their manner of entering the system. The efficacy of cauterization practised fifteen or twenty days after the bite of a rabid animal, has led some practitioners to the conclusion that the poison of rabies is not absorbed, and that being simply deposited in the soft parts which received the wound, its action is at first confined to the nervous extremities which there exist, from whence, in time, it extends to the rest of the nervous system. But in other contagious diseases, the pain, swelling, and redness which occur in the track of the lymphatic vessels and glands, seem to prove the absorption of certain poisons, although some authors have attributed these phenomena to sympathy. Admitting absorption, what is the absorbing surface, if these poi- sons are volatile? Is it the skin, or the mucous membrane of the air passages, into which they are carried with the air ? or that of the alimentary canal where they enter mingled with the food or sali- va? Some authors have supposed that contagious principles cannot act upon the membrane of the stomach, because all the substances introduced into this viscus are there digested and conse- quently become changed. This is an ingenious supposition ; but if we remember that variola has been inoculated by mingling some of the dried scabs with the food and drink, it will be allowed that this supposed decomposition of the virus by the action of the stomach or by the gastric juice is still very doubtful. Others have asserted that contagious principles could be absorbed by those or- gans only in which their symptoms appeared; that variola and scarlatina were contracted by the skin, syphilis by the mucous membranes, etc.; but in the existing state of our knowledge, it is more reasonable to admit that nearly all the contagious agents may be absorbed by every surface with which they come in contact; and that being once introduced into the economy they act specially upon those organs which seem most congenial to each of them. After having studied the action of the evident causes of disease, we shall examine in like manner the predisposing causes, com- mencing with aptitudes. $ II. Aptitudes. The age, sex, temperament, constitution, the degree of comfort, the healthy or diseased condition, and pregnancy, seem neither actively to concur in, nor to oppose, the production of disease. Their influence is appreciated with difficulty, but their action 58 ETIOLOGY. cannot be doubted when general conclusions are drawn from a large number of facts. If, for instance, we collect all the obser- vations which relate to any particular affection, and observe that, in every case, or at least in the greatest number, the disease declares itself at a certain age, and in persons of certain tempera- ment, we must admit that these circumstances constitute favorable, perhaps necessary conditions for the development of such disease. Thus, croup is incontestably more frequent during infancy than at other periods of life, phthisis in youth, arterial aneurism and cancer in adult years, haemorrhage and softening of the brain in old age. Females are more disposed to hysterical affections; males, to hypochondriasis; some epimedics prevail among the poor, others among the opulent, etc. In fact, the influence of aptitudes grows more obscure, as we descend from general conclu- sions to individual applications ; for instance, it does not absolutely follow because scrofula affects children more frequently than adults, and shows a preference for the lymphatic temperament, that these two conditions have always concurred in its production, when observed in such circumstances ; but this does not invalidate the fact that, generally, this age and temperament favor the affec- tion. It is no reason because typhoid fever occurs chiefly in youth, rarely in the adult, and never after the age of fifty-five, that the season of youth has an active agency in its production, but it shows that the liability to contract it, is bounded by certain limits in regard to age, beyond which it does not pass. The influence of age in the development of disease, is far more evident, than that of either temperament, constitution, sex, or degree of comfort. There is no disease incompatible with any temperament or constitution, or with either sex; while certain ages are exempt from some affections, and others are peculiarly exposed to them. It is universally conceded, that of all the conditions comprised under the name of aptitudes, hereditary transmission has the greatest influence in producing disease. In some affections, in- deed, it is an active predisposing cause, rather than a mere aptitude. Children of phthisical origin are in imminent peril of this fearful disease, by reason of that origin alone; and the larger proportion of them are attacked by it, however they may be cir- cumstanced. The influence of birth is less powerful in some other diseases, as rheumatism, stone, apoplexy. Children of parents thus afflicted are, other things being equal, more liable to be affected; but other causes must often concur in order to their production, and even then they are not all attacked. § III. Predisposing Causes, properly so called. Although usually obscure, the action of predisposing causes can often be explained in a satisfactory manner. It is easy to conceive how certain diseases, as indigestion and abortion, may be caused by too tight clothing or corsets. The disposition to plethora, ETIOLOGY. 59 when it follows the use of very nutritious food, and anaemia, which is the effect of abstinence and poor diet, may be easily accounted for. The debilitating influence of excessive evacuations of every sort, and the tendency to inflammation which results from the suppression of habitual evacuations, is quite as clearly explained. So it is with regard to the effect of habitual repose or excessive fatigue upon the health. Nervous disease in anxious or melan- choly persons, or in those who devote themselves exclusively to mental labor, is naturally connected with the causes productive of these affections. The influence of the air and the dwelling is commonly more obscure, although plausible explanations have been given in regard to it. Predisposing causes must not be confounded with predisposi- tions ; the latter depend, but not constantly, upon the former. All persons are not uniformly affected by the same predisposing causes, and a predisposition to disease cannot be accurately determined by the apparent power of the causes which produced it. In one case, a slight predisposing cause will establish a very decided predisposition; in another, a number of such causes, of greater power and longer continued action, will have far less effect, or perhaps none whatever. In many instances we are compelled to acknowledge a decided predisposition to certain diseases in those who have not been exposed to any of their developing causes. Whenever a disease appears without apparent cause, a frequent occurrence in internal pathology, we must have recourse to a latent predisposition to explain its production ; and this doubtless consists in a peculiar modification (whose essence is wholly un- known) either of the whole system, or of one or many of its constituent parts. Thus in pneumonia, erysipelas, or articular rheumatism, it is in almost every case impossible to point out, from a consideration of the antecedent circumstances, the causes which have produced either of these affections. Great obscurity also surrounds the origin of organic diseases. Observation shows us that, in some persons, one organ is much more frequently affected than the rest, or is even the exclusive seat of almost all the diseases which manifest themselves during an entire life, or at any rate, during one or more of its great divis- ions, as infancy, youth, or adult age : in one individual the lungs, in another, the stomach or intestines, in a third the brain, are, in popular terms the feeble organs, that is, the most liable to the action of morbific causes. The advocates of the theory of irrita- tion proposed to call this tendency of an organ to become diseased diathesis, * and they admit pulmonary, gastric, cerebral and uterine varieties; but with most authors and in the usual language of science, this word has a different acceptation. Diathesis is a disposition through whose influence many portions of the body, either simultaneously or in succession, become the seats of spon- taneously developed affections, identical in their nature, although * Jiu6*oig, disposition. 60 ETIOLOGY. variable in external appearance. Consequently, as many sorts of diathesis must be admitted, as there are diseases which show themselves in various organs simultaneously or otherwise, by the agency of a common internal cause : this latter condition is barely admissible. If various forms of inflammation, as peritonitis, pneumonia and ophthalmia, should occur simultaneously in the same patient, each arising from evident external causes, there is no existent diathesis; but if these affections are developed without distinct cause, they are then attributed to a common predisposition, styled inflammatory diathesis. — Rheumatic, gouty, tuberculous, cancerous, gangrenous, herpetic, scorbutic, osseous and aneurismal diatheses, have been admitted; to these, the varicose, melanic, ulcerative and haemorrhagic should be added. The simultaneous development in many parts of the system, of rheumatic or gouty affections, of tubercle, cancer, gangrenous disease, herpetic eruptions, scorbutic symptoms, osseous and aneurismal tumors, varix, melanotic deposits, ulcers, granulations and haemorrhage declares the existence of the corresponding diatheses. We admit also a granular diathesis which most physi- cians regard as a variety of the tubercular. Some authors mention a dropsical diathesis, which is incorrect, since dropsy is in general merely a symptom. The mucous and bilious diatheses are too ill defined for retention among scientific terms. Finally, we do not allow the purulent diathesis of some writers, because it is most frequently a mere infection; nor a syphilitic or variolous diathesis, because these diseases do not recognise an internal cause, but are owing to the evident absorption of a virus whose mode of action is wholly unlike that of diathesis. A peculiar disposition exists in a few instances, which, either in the exercise of some function, or in the impression made upon it by external agents, produces phenomena wholly different from those which are observed in most persons in similar circumstances; such are the syncope caused by the sight of certain objects, or by a kneeling posture maintained for some time; and the urticaria noticed in some individuals whenever they take certain food, as strawberries and shellfish. There are persons upon whom exposure to the exter- nal air has uniformly the same effect during the cold season. Bour- dier saw at the Hotel Dieu of Paris, a man forty years of age, become affected with intermittent fever whenever elastic bougies were introduced into the urethra.* An exceptional predisposition must universally be admitted, through whose agency, in certain persons, like causes always produce remarkable effects. This is called morbific idiosyncrasy. Predisposing and individual causes may act in unison or singly. Their energy is in proportion to their mutual action, or tendency to modify the economy in a similar manner. Among a large population, the individual rarely agree with the general predispositions, from which it results that all the inhabi- * Theses de la Faculte de Medicine de Paris, annie 1809, No. 17. ETIOLOGY. 61 tants of a district are very seldom simultaneously attacked by disease, except it spring from a contagious principle, that is, a spe- cific cause acting independently of predisposing causes. An affec- tion uniformly developed by the latter, hardly ever attacks more than one third or one quarter of a population; most usually only one tenth, one twentieth, or even a less proportion. We can sometimes be certain, that those attacked by the prevailing malady, are those in whom the influence of general predisposing causes has rendered more active that of the individual pre- disposing causes. When, for instance, bilious affections are very common, persons of bilious temperament, who live chiefly on animal food, etc., are more often attacked, while the sanguine or lymphatic, being less impressible by general predisposing causes, possess a resisting power in their very constitution. Thus, other things being equal, the latter are more rarely and less severely affected, while the former are more generally attacked and with more violence and rapidity. There are, however, many excep- tions to this rule. 1. Individual predisposing causes are sufficient of themselves to produce most diseases. There is no affection which may not be occasionally developed in isolated individuals, independently of general predisposing causes. Angina and pneumonia, for instance, although more frequent in certain seasons, may occur in all, through the influence of individual predisposing causes only. Often, while certain diseases prevail under the influence of general causes, indi- vidual predisposing causes develope affections of a wholly different nature. It is in this way that inflammatory diseases may appear in certain persons inhabiting places where dropsy and scurvy are endemic. 2. On the other hand, general predisposing causes, when exceed- ingly active, may exert an influence independently of the individ- ual predisposants, and even notwithstanding the resistance they offer. Thus it is that diseases developed during public calamities, as famines, sieges, etc., fall upon all classes of society, almost without distinction; neither is any temperament or age exempted, as has been observed in many epidemics, particularly at Modena* and Naples.f As regards their relative energy, then, we find that general pre- disposing causes may neutralize the effect of individual causes, and bring on diseases entirely in opposition to the latter, and vice versa. Before concluding what we have to say of predisposing causes, we remark, that if there be certain conditions which dispose to disease, there are likewise many which are preservative of health. Without mentioning in this connection that unknown power called vital force, which, as has been said, appears to struggle incessantly against the destructive agents which surround us, there are condi- * Ramazzini, 1690-93. f Sarcone, 1764. 6 62 ETIOLOGY. tions which exempt us from certain affections; habit, in particular, is one of these. By it the most indigestible articles of food are par- tially deprived of their injurious effects, and the pernicious energies of the most subtle poisons destroyed; the Turks use opium with impunity, and Mithridates, according to historians, became insen- sible to poisons. We must not suppose, however, that the daily use of deleterious substances has no injurious effect upon the econ- omy ; habit does not wholly free us from their action; it merely alters and strikingly enfeebles it. The power of certain contagious principles seems to be exhaust- ted in like manner by the force of habit. In places where yellow fever is endemic, the inhabitants are not attacked by it, as at Havana and Vera Cruz, for instance. The Turks resident at Con- stantinople seem to be as much habituated to the principle of the plague, which is in almost continual action in some parts of the city, as they are to opium by daily use. We may with as much propriety conclude that if the visiting physicians of hospitals are not more frequently than others the victims of typhus when widely epidemic, it is because they have become accustomed to the action of the contagious principle before it has acquired its full power. The force of habit goes yet farther, and deprives even chemical agents of a portion of their influence over living tissues. There are those who handle with impunity bodies at a very high temper- ature, as burning coals, or iron bars whose opposite extremity is incandescent; others have accustomed themselves to swallow boil- ing liquids without any sensible inconvenience. Tartra relates the curious fact, that a woman given to intemperance, had passed from the immoderate use of wine to that of brandy, then of alco- hol, and even of ether ; at last, unaffected by these liquids, she fin- ished by drinking nitric, acid, without experiencing from it any remarkable injury.* It is hardly necessary to add, that age, sex and temperament are all conditions which should be considered preservative against cer- tain affections. Primitive scirrhus or aneurism are never observed in infancy; one instance only of croup is recorded in old age. We have already seen that some contagious diseases attack the same person but once during life; those who have been affected, are consequently exempt. A very extraordinary, although very well known phenomenon, is the reciprocally preservative property of variola as regards vaccinia, and vice versa. This fact which is unique in the history of contagious disease, naturally leads us to suspect a similarity of origin in these affections. Finally, there exists a fortunate disposition, whose nature is un- known, but whose effects are appreciable, which protects from cer- tain maladies. There are some individuals who appear to be insusceptible of the contagion of variola, or vaccinia. Others ex- pose themselves daily to syphilis with impunity. In all the instances of epidemic typhus or yellow fever there are some who * Empoison, par V acide nilr., p. 124. ETIOLOGY. 63 brave the contagion and escape the disease. When the plague was at Marseilles, the venerable Belzunce, patriarch of the city, was not affected by it, although almost constantly among the sick, aiding them in every manner. In the black plague which deso- lated the south of France, in 1347, another fact, no less remarka- ble, was noticed; of thirty-five monks who dwelt in the monastery of Mont Rieux, one only escaped the contagion ; this was Gerard, brother of the celebrated Petrarch, who took care of all the breth- ren and also buried them. $ IV. We have considered the mode of action exhibited by spe- cific and predisposing causes in developing disease; it remains for us to notice that of the occasional causes. The influence of the latter is not by any means so great; they act only when there exists a predisposition. Thus, of ten persons who may commit an excess of the table, or who may be exposed to cold, etc., there will be, at farthest, but one or two whose health will be disturbed, and sometimes out of a larger number there will be none affected. Moreover, these causes have no influence upon the sort of affection which is developed; the same occasional cause may, as we have seen, excite any disease, and the same disease may result indiffer- ently from any occasional cause. Such a cause is, as it were, a shock given to the system; it does not affect those in firm health; in others it may develope any affection whatever. Such is the mode of action of each kind of morbific causes. There is a certain number of diseases in whose production some of these three classes of causes concur; there are others where the disease arises exclusively from a specific cause, or from one or more predisposing causes. Asphyxia always depends on a specific cause; typhus requires the influence of some predisposing cause in the majority of cases; and sometimes an occasional cause, as ter- ror, or too strict diet, may excite its attack ; plethora and inflam- matory fevers are almost always exclusively produced by predis- posing causes; no affection arises solely from an occasional cause. The knowledge of causes is not absolutely necessary in particu- lar cases. When the disease is due to specific causes, they are easily appreciated, but the predisposing causes, which are usually obscure, frequently escape the physician's sagacity. The kind of disease developed, may in some cases lead to the suspicion of the causes which have produced it, and serve as a guide in the search for them; but in many other instances these causes remain uncer- tain, or even unknown. In respect to occasional causes, as they are immediately antecedent to the disease, they attract more par- ticularly the patient's attention, which cannot fail to instruct the physician ; but a knowledge of them is generally of slight impor- tance, and many diseases make their appearance without their influence. I 64 ETIOLOGY. ARTICLE FIFTH. Division of Diseases relatively to the Causes which produce them. Diseases arising under similar conditions, or which offer cer- tain points of resemblance as respects their causes, have been grouped together and possess certain interesting relations. The principal groups to which this etiological division has given rise are those of innate and acquired, sporadic, endemic and epidemic dis- eases. By innate or congenital diseases {morbi cognati, congeniti) is understood those exhibited by the child at birth. They are not all hereditary, neither do all hereditary diseases appear at the time of birth. The latter have existed, or are still present in the parents, and this does not necessarily occur in regard to the former. An affection may be both hereditary and congenital. Under the title acquired diseases {morbi acquisitl, adventitii) are included those not commencing till after birth and independent of hereditary disposition. All diseases may come under this head except deformities. Sporadic diseases {morbi sporadici*) are those which attack a single individual, or a certain number of isolated persons. They depend especially upon the predisposing causes; for the epithet sporadic is not given to affections induced by specific causes. We do not say that wounds, fractures, and asphyxia are sporadic; this term is applicable only to those diseases whose development is apparently spontaneous. Sporadic diseases are, of all, the most common; they appear at all seasons, at every age, and in all climates, under the action of individual causes. Diseases which attack a mass of individuals at once, have been styled pandemic {morbi populares); these have been subdivided into several series, according to the circumstances which accom- pany their development. Those which appear every year at nearly the same time, are called annual {morbi annul, annlversarii); those which manifest themselves uninterruptedly for many seasons, or one or more years, are known as stationary {morbi stationarii) ; those occurring at various seasons, and modified only by prevalent affections, are termed intercurrent {morbi inter currentes). At the present time these names are generally abandoned, and two classes only of popular diseases are admitted, endemic and epidemic. Endemic \ diseases {morbi endemici) are those produced by the concurrence of causes constantly or periodically in operation in certain situations, so that the diseases resulting from them are con- stant, or at any rate, appear at fixed periods, affecting, in every * SnltQw, to scatter here and there. f Ev, in ;