Book 
 
 qass_ J V^-tSk 
 
 
/ 
 
 Dunglisori's American Medical Library. 
 
 ESSAYS 
 
 
 ON THE 
 
 SOURCES AND MODE OF ACTION 
 
 OF 
 
 FEVER. 
 
 BY WILLIAM DAVIDSON, M. D., 
 
 SENIOR PHYSICIAN TO THE GLASGOW ROYAL INFIRMARY, ETC. ETC. J 
 
 AND 
 
 ALFRED HUDSON, M. B., T. C. D., 
 
 i 
 
 PHYSICIAN TO THE NAVAN FEVER HOSPITAL. 
 
 PHILADELPHIA! 
 PUBLISHED BY A. WALDIE, 46 CARPENTER STREET. 
 
 1841. 
 
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I. 
 
 THACKERAY PRIZE ESSAY. 
 
 Essay on the Sources and Mode of Propagation of the Con- 
 tinued Fevers of Great Britain and Ireland. 
 
 BY WILLIAM DAVIDSON, M. D., 
 
 Senior Physician to the Glasgow Royal Infirmary, Lecturer on Materia Medica, Member of the 
 Faculty of Physicians and Surgeons of Glasgow, &c. 
 
 CHAPTER I. 
 
 On the Sources of Continued Fevers. 
 
 Numerous kinds of continued fevers have been described by 
 authors ; but many of these have been found, on investigation, 
 only particular varieties, in place of being distinct species. This 
 has been particularly the case with typhus, the most prevalent 
 kind of continued fever in this country; and it may be accounted 
 for, from its numerous and diversified complications giving rise to 
 various and multiform symptoms. The pathology of typhus, how- 
 ever, of late years has been considerably advanced ; and it is now 
 established, that this disease may be either simple or complicated, 
 with organic affections of one or all of the different cavities of the 
 body. 
 
 We shall not, at present, enter into any discussion respecting the 
 various kinds of continued fever that are to be met with in the 
 United Kingdom; but as perspicuity in arrangement requires some 
 classification, we shall adopt the following, reserving the illustra- 
 tions upon which this classification is founded for a future part of 
 the essay : — 
 
 1. Typhus. 
 
 2. Febricula or Simple Fever. 
 
 3. Gastric or Intestinal Fever. 
 
 These affections seem to be distinct species of disease, differing 
 
 in their symptoms, causes, and laws ; and are generally treated in 
 
 private practice and in hospitals as continued fevers. To this list 
 
 l* 
 
4 DAVIDSON ON THE CAUSES OP FEVER. 
 
 may, perhaps, be added bronchitis, which, although an inflamma- 
 tory affection, is more frequently confounded with them than any 
 other disease. 
 
 Sect. I. — Sources of Typhus. 
 
 It appears to us quite unnecessary here to describe what is un- 
 derstood by typhus fever ; as we assent to the general correctness 
 of our standard authors upon this subject, and as some of their 
 descriptions will be quoted in another part of this essay. At the 
 same time, it may be remarked that typhus possesses an advantage 
 over the other forms of continued fever, in having a distinctive 
 characteristic, viz. the eruption, which is present in none of the 
 others, and which is now almost universally acknowledged as de- 
 cisive of its existence. It must, however, be admitted that typhus 
 can and does occur, without its characteristic eruption ; but it is 
 equally certain that the large majority of patients who have deci- 
 dedly the general typhoid symptoms, are more* or less spotted with 
 this efflorescence. It is therefore the sources of typhus, as gene- 
 rally so characterised, which we mean to trace in this section. 
 
 There is considerable diversity of opinion amongst British phy- 
 sicians respecting the causes of continued fevers; but certainly the 
 majority of authors have adopted the belief that typhus is propa- 
 gated by contagion. The opinion of the majority appears to be 
 supported by the facts connected with the progression of the dis- 
 ease ; it shall therefore be our object to establish this point. It is 
 not intended, however, to enter into any speculations respecting the 
 primordial source of the contagion of typhus; for the sources from 
 which it, as well as that of other contagious fevers, originated, is 
 involved in absolute obscurity ; and though we could trace them 
 to the most remote era in antiquity, the same difficulty would be en-' 
 countered. Some authors, apparently to get rid of this difficulty, 
 and to account for the occurrences of typhus where no contagion 
 could be traced, have adopted the opinion that it may be generated 
 by common causes, such as impure air, filth, <fcc, and be after- 
 wards capable of propagation by contagion. 1 The- argument of 
 analogy is directly opposed to this belief; for if, in nature, there be 
 no exception to the law, that two causes are never required to pro- 
 duce precisely the same effect, it will follow that whatever cause 
 can be best reconciled with the phenomena of typhus, must be con- 
 sidered the true source of the disease. But, in order to apply this 
 principle more immediately to the subject, it may be necessary to 
 appeal to the various morbid poisons, the laws of which are known 
 and generally admitted. The first we shall notice, are those which 
 are admitted by all writers to be propagated by one cause only ; 
 
 1 The terms contagion and infection are used synonymously, as indicating 
 the ponderable or imponderable matter, which is generated in a diseased 
 living body, and which is capable of producing the same disease when 
 applied to another. 
 
DAVIDSON ON THE CAUSES OF FEVER. 5 
 
 viz. matter, whether ponderable, as the pus contained in a variolous 
 pustule, or imponderable, as the effluvia issuing from a patient 
 labouring under small-pox. Measles, scarlet fever, hooping-cough, 
 are propagated only by the effluvia which are generated by the 
 patient ; and though the material body by which it is effected can- 
 not be collected into vessels, like the various gases, still the proofs, 
 upon which their contagious qualities are based, are as unquestion- 
 able as those of small-pox. Almost all the contagious diseases of the 
 skin, such as syphilis, scabies, the yaws, si wens, &c, furnish ex- 
 amples of propagation by only one cause, viz. contagion. There 
 are no doubt authors who maintain that some cutaneous diseases 
 are generated by filth, &c, such as some of the infectious species 
 of porrigo; but of this there is no proof; and in all probability it is 
 equally unfounded, as was a similar hypothesis respecting the 
 origin of scabies. These diseases always retain the same charac- 
 teristics ; the one is not convertible into the other ; and no known 
 combination of them can generate a new contagion capable of per- 
 petuating a new disease. A specious objection might be brought 
 forward against the introduction of an analogy from chronic con- 
 tagious diseases, which are only propagated by contact, according 
 to the general belief; and besides are regulated in other respects by 
 different laws, whereas typhus is propagated only by effluvia. It 
 is quite evident that a class of diseases may be recognised by one 
 leading and undeviating law, while they differ in many of their 
 subordinate characters; and yet this peculiar law of similarity be- 
 tween them may be as certain and definite as if they had been 
 united into one family by all their habits. The effluvium which 
 issues from a small-pox patient must be as essentially matter, as is 
 the fluid of a variolous pustule ; for though the first cannot be col- 
 lected in a separate form, it must possess one or other of the pro- 
 perties of small-pox matter, else it could not induce the disease: 
 the only difference between them consisting in this, that the conta- 
 gious matter is fluid in the one case and effluvial in the other. It 
 is necessary that the foregoing observations respecting contagious 
 diseases be kept in view; for upon the analogy between them and 
 typhus we mean to establish an argument, that the latter disease 
 can only be propagated by one cause. If it be true, then, that all 
 the contagious fevers known can be propagated only by contagious 
 matter, and by no other cause, however much their contagious 
 qualities, their prevalence, and their fatality may be increased by 
 other causes, it must follow from the law of analogy that if typhus 
 can be proved to be contagious, it must also be propagated only by 
 one cause, viz. contagion. We shall, therefore, endeavour to prove 
 this point ; and, in the outset, it may be stated, that we do not mean 
 to fatigue the reader by stories about fomites and persons who have 
 carried the contagion about them for months or years, nor to hunt 
 out a particular individual who has conveyed it from one town to 
 another. In place of accumulating evidence of this kind, which 
 although sometimes very conclusive, is in other cases somewhat 
 
6 DAVIDSON ON THE CAUSES OF FEVER. 
 
 questionable, we shall select a few facts from the history of our 
 British and Irish hospitals, which, we trust, will be sufficient for 
 our purpose; for if it can be established from these documents that 
 the disease was contagious in all the large hospitals of Britain and 
 Ireland, then it must be more or less so in every other place. In 
 selecting the facts, we shall adduce the most conclusive instances, 
 such as where the whole, or almost the whole, of the attendants of 
 the patients affected with typhus were infected; for were the whole 
 body of evidence existing on this subject accumulated in this essay, 
 the argument would be encumbered, and the proofs perhaps ren- 
 dered less convincing. Those who deny the existence of typhous 
 contagion, may assert that this is unfair, and that those hospitals 
 also should be brought forward, where the medical and other 
 attendants were rarely affected. As we shall, however, notice this 
 and other objections elsewhere, it need not be farther alluded to 
 here. Drs. Barker and Cheyne, in their admirable report of the 
 fever which prevailed in Ireland during the years 1817-18-19, 
 state that "in the hospitals of the House of Industry of Dublin, no 
 clinical clerk or apothecary escaped an attack of the disease ; and 
 on the 20th of January, 1819, it was reported to government that 
 five of the medical attendants of the House of Industry were at that 
 time lying ill of the disease. In the city of Cork, nine physicians, 
 in attendance either on dispensaries or fever hospitals, were 
 attacked ; every medical attendant at the South Fever Asylum, in 
 that city, suffered. At the hospitals of the House of Industry, one 
 hundred and seventy persons were employed in different offices of 
 attendance on fever patients ; and from this part of the establish- 
 ment were recorded one hundred and ninety eight cases of fever." 
 In Dr. Crampton's medical report of the department of Steevens' 
 Hospital, it is observed, "that, with the exception of Dr. Harvey 
 and himself, all those concerned in attendance on the patients 
 caught the disease; none of the nurses, none of the porters, barbers, 
 or those occupied in handling, washing, or tending on the sick, 
 escaped, and many of them had relapses and recurrences of fever.'" 
 Dr. Bracken, in his report of the Fever Hospital of Waterford 
 for 1818, states that "there were twenty-seven attacks and relapses 
 of fever among the nurses, servants, and porters, whose number 
 fluctuated according to the demand for them, but who, on an ave- 
 rage, may have been about twenty-two during the year." He far- 
 ther states that "the present year, 1819, bears a close resemblance 
 to the last, in respect to the nurses and servants being attacked 
 with fever, eighteen of the former having suffered under the dis- 
 ease; seven of them once, three twice, and one three times. The 
 apothecary, who had not been long in the hospital, caught fever 
 and relapsed twice. During his illness, a young man, who per- 
 formed part of his duties, was attacked after a short attendance. A 
 temporary apothecary was then engaged for a few weeks ; but he 
 
 1 Barker and Cheyne's Report of the Fever in Ireland, vol. i. p. 135. 
 
DAVIDSON ON THE CAUSES OF FEVER. 7 
 
 had not been many days in his new employment when he also con- 
 tracted a fever." 1 
 
 Drs. Barker and Cheyne remark that clergymen, who visited 
 typhus patients in Ireland during the epidemic, were also observed 
 to suffer in a very remarkable degree ; and they quote the follow- 
 ing passage from Dr. Stokes's Essay on Contagion, which was 
 published at a time when the fever had made little progress in 
 Dublin : — " The deaths from fever recorded in Saunders's News- 
 Letter, from August 1st to December 12th following, are sixty- 
 four, and of these nineteen are of clergymen of some of the different 
 persuasions, or of medical men of different descriptions, which ap- 
 pear greater than the proportion which these two classes bear to 
 the whole of those whose deaths we may suppose were mentioned 
 in that manner." 2 Dr. Tweedie, in his Clinical Illustrations of 
 Fever for 1828-29, observes that " the London Fever Hospital is 
 placed in an open space, situated in the vicinity of the metropolis, 
 close to the Small-pox Hospital. Both these establishments stand 
 in the centre of a large field, where the production of malaria is ex- 
 tremely improbable. I can state from the most authentic sources, 
 that every physician who has been connected with it, with one ex- 
 ception (the late Dr. Bateman), has been attacked with fever during 
 his attendance, and that three out of eight physicians have died. 
 The resident medical officers, matrons, porters, laundresses, and 
 domestic servants, not connected with the wards, and every female 
 who has ever performed the duties of a nurse, have one and all in- 
 variably been the subjects of fever ; and to show that the disease 
 may be engendered by fomites in clothing, the laundresses, whose 
 duty it is to wash the patients' clothes, are so invariably and fre- 
 quently attacked with fever, that few women will undertake this 
 loathsome and frequently disgusting duty. Last summer, a most 
 convincing illustration of contagion occurred. The present resi- 
 dent medical officer was attacked with fever, and it was necessary, 
 in consequence, to appoint some one to perform his duties during 
 his illness. The first person who officiated for him resided con- 
 stantly in the house during the day, but took the precaution of 
 sleeping at home. He was, of course, very much exposed in the 
 wards in the performance of his duties. These, however, were 
 soon interrupted by an attack of fever, which confined him for a 
 considerable time. The duties were then undertaken by a medical 
 pupil, who had completed his education, and entered the hospital 
 in the most robust health. He had been taught, and did implicitly 
 believe, in the non-contagious nature of fever, and ridiculed the 
 idea of any personal danger from residing in the hospital. He per- 
 formed the duty of house-surgeon for ten days only, when symp- 
 toms of a severe fever appeared." 3 
 
 1 Barker and Cheyne's Report of the Fever in Ireland, vol. i. p. 276. 
 
 2 Ibid. vol. i. p. 138. 
 
 3 Tweedie's Clinical Illustrations of Fever, p. 87. 
 
8 DAVIDSON ON THE CAUSES OF FEVER. 
 
 Dr. Tweedie also adduces some important facts connected with 
 the fever which prevailed in Edinburgh during the year 1817, 
 which are the following: — Owing to the prevalence of fever at 
 Edinburgh in 1817, it was necessary to apply to government to 
 permit Q,ueensbury House to be employed as a fever hospital : " In 
 the immediate neighbourhood of this extensive building fever was 
 decidedly less prevalent than in any other quarter of the town. All 
 those, however, who resided in the hospital, including the resident 
 house-surgeon, clerks, apothecary, and nurses, were successively 
 attacked." The following is Professor Alison's report on this sub- 
 ject. u When dueensbiiry House was formerly occupied by fever 
 patients, every resident clerk and every nurse in the house were 
 successively affected with the disease; and since it was reopened in 
 December last (1826), the resident physician, two of the clerks 
 (who have not been resident, but have been several hours in the 
 day in the house), the apothecary, several servants, and all the 
 nurses except two, in all above forty individuals, who had neces- 
 sarily close intercourse with the sick there, have had fever. If this 
 be the effect of a malaria, it must be a very virulent and effective 
 one, and it is reasonable to expect that some record of similar 
 visitations in the former history of the building would be found. 
 But Q,ueensbury House has existed for about a century-; it was 
 long occupied as a private dwelling-house by the noble family of 
 that name ; afterwards it was occupied by a number of families, 
 and afterwards as a soldiers' barrack ; and yet no record can be 
 found of its having been, during these changes ; the seat of an epi- 
 demic fever. If a malaria has existed, therefore, in that house, it 
 must, on both occasions, have sprung up exclusively at the times 
 when fever patients were removed thither and lasted only during 
 their stay. During the present epidemic (1827-28, as well as that 
 of 1817-19), many of the clerks and nurses employed in the Royal 
 Infirmary have taken fever. Since November last, six of the clerks 
 employed in the clinical wards only, four of those employed in the 
 ordinary wards, and twenty-five nurses or servants have taken 
 fever. All these persons had necessarily frequent and close inter- 
 course with the fever patients in the house, having been employed 
 more or less constantly in the fever wards, excepting only four of 
 the servants. Of these four, two had been employed in the laundry, 
 where the linen from the fever wards was washed. One was a 
 porter employed at the gate, who would, of course, have communi- 
 cation with the fever patients at their entrance and dismissal, as 
 well as with their relations coming to visit them; and one was a 
 nurse employed in the servants' ward, but who was in the habit of 
 visiting the fever wards." He adds further: " No one of the nurses, 
 whose duty has confined them to the medical or surgical wards, 
 where no fever patients were admitted, has taken fever, with the 
 single exception of the woman in the servants' ward above men- 
 tioned ; and of the numerous patients in these ordinary wards, the 
 only one who ims taken fever, within my knowledge, during the 
 
DAVIDSON ON THE CAUSES OF FEVER. 9 
 
 present year, was a patient in the men's general clinical ward, who 
 lay in the bed next the door that communicates with the clinical 
 ward."' Dr. West, in his account of the cases of typhus exanthe- 
 maticus that occurred in St. Bartholomew's Hospital in 1837-38, 
 states that "since last summer, eleven gentlemen who were in the 
 habit of frequenting the hospital have been attacked by the fever, 
 to which three have fallen victims ; sixteen nurses and twenty-one 
 patients admitted for other affections, have likewise suffered from 
 the disease, which terminated fatally in ten instances, and I do not 
 doubt but that many similar cases occurred which did not come 
 under my notice." 2 Dr. Roupell, also, gives similar testimony in 
 reference to St. Bartholomew's Hospital, and states that " amongst 
 the nurses in attendance upon the sick, in that establishment, infec- 
 tion was almost universal." 3 In the Glasgow Fever Hospital, which 
 is capable of containing 220 patients, during the last six or seven 
 years almost every clerk and nurse of that establishment have 
 caught fever while acting in the wards, unless they had previously 
 laboured under the disease. On the other hand, the nurses con- 
 nected with the medical and surgical wards, in the adjoining build- 
 ing, have almost uniformly escaped. Occasionally a case has 
 appeared in the medical and surgical wards; but this fact ought to 
 be coupled with the statement, that now and then typhus cases are 
 sent, by mistake, into the medical wards, and cases of bed-sores, 
 gangrene of the feet, &c. are transmitted from the fever hospital to 
 the surgical wards. Dr. Cowan states that "All the gentlemen 
 who have acted as clerks in the fever hospital for many years past 
 have been attacked with fever, unless they had it previously to 
 their election. During last year, twenty-seven of the nurses of the 
 establishment were seized with fever, and five of them died: several 
 of the students have been affected. One gentleman who acted as 
 apothecary died in the house ; and if I have escaped, it must be 
 attributed either to being past the period of life at which fever 
 usually takes place, or to my being secured by having had two 
 dangerous attacks at an earlier period of my career, when acting as 
 physician's clerk in the infirmary, during the epidemic of 1816- 
 17-18." 4 
 
 Dr. Mateer gives a table of 9,588 cases, which were admitted into 
 the Belfast Fever Hospital, from 1818 to 1835, showing the number 
 of patients who had any communication with affected persons, 
 either by residence in the same house, or by belonging to the same 
 family. He draws the following conclusion from the table: "It 
 thus appears that the number of families where contagion is trace- 
 able is 1,856, that the total number of persons belonging to them is 
 7.246, making an average of nearly four individuals to each family; 
 
 1 Tweedie's Clinical Illustrations of Fever. Edinb. Med. and Surg. Jour- 
 nal, vol. xxviii. p. 238. 
 2 Ibid., July, 1838, p. 143. 
 3 Roupell on Typhus. 
 4 Cowan's Vital Statistics, p. 26- 
 
10 DAVIDSON ON THE CAUSES OP FEVER. 
 
 and that the single cases, where the disease seemed to have arisen 
 from other sources, amount only to 2342." 1 
 
 This assemblage of facts has been drawn from the large hospitals 
 in England Scotland, and Ireland, and the observations have been 
 made during various years and during different epidemics by gen- 
 tlemen of the highest talents and respectability ; their authenticity 
 cannot, therefore, for a moment be questioned. The simple relation 
 of these facts would, we think, with the majority of men, produce 
 conviction that fever was at least contagious in these hospitals, pro- 
 vided the mind was not preoccupied with an opposite theory; but a 
 few observations will tend to produce a proper estimation of this 
 testimony. It is quite obvious, that where a much larger proportion 
 of persons is affected with any particular disease, in any particular 
 place, than occurs amongst the general community, or in any par- 
 ticular grade of society, there must be some local cause for that 
 increased ratio. This has, manifestly, been the result in the fever 
 hospitals that have been enumerated ; for in all, a very large 
 majority of the attendants, and in some the whole of them, were 
 affected with fever. Now, no one will contend, that even amongst 
 the lower classes (who generally suffer from fever to the greatest 
 amount), such a proportion has ever been maintained, even in our 
 most severe typhoid epidemics ; but if the number of hospital clerks 
 be taken and compared with the unaffected number, in the particu- 
 lar grade of society to which they belong, such an attempt would 
 be ridiculous ; for the united testimony of the hospital physicians 
 of England, Scotland, and Ireland (whose statements we have 
 already quoted) amounts to this, that almost every clerk of a fever 
 hospital has laboured under fever during some period of his attend- 
 ance upon it. It may be contended, in answer to this argument, 
 that the atmosphere of the hospitals was contaminated by the 
 exhalations arising from the number of patients an»d -th^-want of 
 proper ventilation ; but the same process of -atmospheric deteriora- 
 tion ought to take place, in the medical and surgical wards, if they 
 be equally filled, which is generally the case; and in the latter 
 wards there are often, in addition to the ordinary exhalations, the 
 effluvia arising from wounds, ulcers, &c, yet typhus rarely, and 
 only in sporadic cases, springs up there. 
 
 The opponents of contagion, however, endeavour to explain the 
 prevalence of fever among hospital attendants by the hypothesis, that 
 the same cause that produced it in the filthy, ill-ventilated houses of 
 the lower classes is in existence in these institutions; viz., a peculiar 
 malaria, generated chiefly in large towns. If this hypothesis were 
 true, it would follow, as a necessary consequence, that the other 
 parts of the building, beingf similarly situated, would be subjected 
 to the same malarious effluvia, and hence its inmates would be 
 affected with the same kind of disease ; but this has never occurred 
 in any of the large hospitals already alluded to, nor in any other, 
 
 'Dublin Journal of Medical Science, vol. x. p. 35. 
 
DAVIDSON ON THE CAUSES OF FEVER. 11 
 
 so far as we are aware, where patients affected with typhus are 
 kept exclusively in one place. Again, it may be asserted by the 
 noncontagionist, when driven to the last extremity, that though 
 malarious effluvium be not generated in an hospital, it may be 
 carried there by the clothes of the patients, and the attendants may 
 be infected by coming into contact with them. The analogy of 
 malarious diseases is in opposition to this belief; for it is not found 
 that a patient labouring under ague infects any person who has 
 not been in the malarious district; neither, according to the general 
 belief, does a patient labouring under yellow fever, when removed 
 from the quarter where he caught the disease, excite contagion in 
 the vicinity of his new residence. But as this supposed typhoid 
 malaria may be assumed to possess something sui generis, an 
 argument stronger than analogy can be adduced, viz., the impossi- 
 bility of carrying any principle of that kind into the wards. It is 
 the practice, in many of the large fever hospitals, to remove the 
 clothes of the patients, to bathe them, shave their heads, and give 
 them clean linen, before they are sent into the wards. This plan is 
 adopted in the Glasgow Fever Hospital, and the following is one of 
 the regulations of the Waterford Hospital. 
 
 Dr. Bracken states, that " according to one of the regulations of 
 the hospital, every patient has his hair closely cut at the time of his 
 admission ; he is also well washed with warm water and soap, and 
 supplied with linen before he enters the sick ward." 1 
 
 Sect. II. — On the Analogy of Typhus to Exanthematous Fevers. 
 
 Having discussed the most important and specious hypotheses 
 which have been brought forward to explain the general and ultra- 
 proportionate prevalence of fever among the attendants of the sick 
 in large hospitals, independent of the operation of contagion, we 
 shall take notice of the general objections to the doctrine of conta- 
 gion in typhus fever; and these maybe comprehended in the state- 
 ment, that it is not characterised by the laws of other contagious 
 fevers. Before entering upon this part of the subject it may be 
 remarked, that more importance is generally attached to this argu- 
 ment than it merits; for though, in the absence of facts, analogy is 
 the most conclusive process of reasoning that can be employed, yet, 
 undoubtedly, when facts are opposed to the application of this 
 principle in any individual case, the facts have the preponderance 
 over the analogy. And, though we were unable to prove that 
 typhus was analogous, in its leading characteristics, to the conta- 
 gious exanthemata, yet if it be admitted that there is no theory 
 which can explain satisfactorily the facts regarding the prevalence 
 of the disease in hospital attendants, except that of contagion, the 
 case would be conclusively determined, even in opposition to the 
 analogy, and would be set down either as an exception, or as one 
 
 1 Barker and Cheyne on Fever, vol. i. p. 259. 
 
12 DAVIDSON ON THE CAUSES OF FEVER. 
 
 of a new series of contagious diseases. It fortunately happens, 
 however, that the law of analogy will be little violated by corn- 
 paring typhus with the contagious fevers, for in its leading charac- 
 teristics it resembles them pretty closely; at the same time it ought 
 to be observed, that typhus fever has only, of late years, been 
 examined with sufficient care, as to many points, connected with 
 its history, laws, and pathology, and that it labours under the dis- 
 advantage of being frequently confounded with other continued 
 fevers, to which, in its early features, it bears an intimate resem- 
 blance ; so that the same certainty of analogical conclusion cannot 
 be expected, as exists among the other exanthematous fevers. We 
 shall endeavour, however, to show, by the facts which shall be 
 quoted, that typhus comes distinctly within the range of their 
 analogy, and that though it is not so regular in its progress, nor so 
 certain in its eruption as smallpox or measles, yet that it differs as 
 little from scarlet fever, in these respects, as the latter differs from 
 smallpox. 
 
 The principal laws of the contagious exanthemata are the fol- 
 lowing : 
 
 1. The contagion can be traced in families, hospitals, schools, &c, 
 and those exposed to it are very generally infected. 
 
 2. They only affect persons once during their lives. 
 
 3. They are characterised by an eruption, which has a rise, pro- 
 gress, and decline, and the disease cannot be checked in limine. 
 
 1. The contagion of typhus is traceable in hospitals, schools, 
 families, fyc. In determining the contagious nature of any disease, 
 it is not necessary that we should be able to trace every case, or 
 even the majority of a particular amount of cases, to a communica- 
 tion with an infected person, or to exposure to a particular fomites; 
 for this would imply that we could, like an American Indian, dis- 
 cover the trail of a patient and trace him through all the windings 
 of a large city, and, besides, should investigate the history of every 
 individual whom he has passed or rubbed shoulders with in every 
 narrow and dirty alley. Even in smallpox, measles, and scarlet 
 fever, any attempt of this kind to trace the contagion regularly 
 would be fruitless, and for the very same reason. Smallpox was, 
 at one period, believed by some authors to originate in filth, because 
 it was found impossible, in numerous cases, to account for its ex- 
 istence in certain localities upon the principles of contagion. Dr. 
 Adams remarks, that " many children born in London live for seve- 
 ral years without receiving the smallpox. In the same neighbour- 
 hood a person arrives from the country, and without any apparent 
 intercourse with an infected person is attacked by the disease." 1 
 
 Independent of the many exposures to infection, which are per- 
 fectly unknown and undiscoverable by the patient, it is very diffi- 
 cult to ascertain the facts connected with the ordinary movements 
 of a patient, which, in many cases, can only be elicited by tedious 
 
 1 Adams on Morbid Poisons. 
 
DAVIDSON ON THE CAUSES OF FEVER. 
 
 13 
 
 cross-examinations; so that this method of determining the point is 
 liable to many objections, and greatly inferior in conclusiveness to 
 the evidence derived from the spread of a disease in any large 
 school or hospital ; but, certainly, it tends to prove the doctrine of con- 
 tagion in typhus as much, if not more, than it does in smallpox, &c, 
 as will appear from the following table. The whole of the eruptive 
 cases of typhus, in which this point was investigated, and that were 
 admitted into the Glasgow Fever Hospital from 1st May to 1st 
 November, 1839, are included only in this table, the males and 
 females being classed together. 
 
 
 Exposed to 
 Contagion. 
 
 Uncertain. 
 
 Cold. 
 
 Total 
 No. of Cases. 
 
 Eruptive typhus . . 
 Febricula .... 
 Smallpox .... 
 Scarlet fever . . . 
 
 Measles .... 
 
 i 
 
 201 
 
 10 
 
 7 
 
 169 
 
 28 
 
 19 
 
 4 
 
 2 
 
 53 
 
 22 
 
 1 
 
 1 
 
 423 
 
 60 
 
 27 
 
 4 
 
 3 
 
 The number of eruptive cases of typhus admitted into the fever 
 hospital, both in the period included in the above table and also 
 during the previous six months, who have been exposed to conta- 
 gion, we have always found greater than" in those affections not 
 characterised by the exanthema ; and it is remarkable that, not- 
 withstanding the most careful inquiries, only seven cases of small- 
 pox could be traced to contagion out of twenty-seven. 
 
 Dr. Cowan states, that "of the patients admitted into the fever 
 hospital last year, 472 males and 589 females, forming 47 per cent, 
 of the whole, either ascribed the origin of their disease to contagion, 
 or had been exposed to its influence." 1 
 
 The propagation of the typhoid contagion is also intimately con- 
 nected with filth and deficient ventilation; and there are few medi- 
 cal facts better ascertained than the close connection of pestilence 
 with these circumstances. Dr. Hancock remarks, that "the con- 
 nection of plague with filth and impure air, and crowded ill-con- 
 structed cities, and with certain seasons and climates and states of 
 the atmosphere, calculated to engender mischief though not accu- 
 rately defined, has been so repeatedly observed in different countries 
 as to stand on a far more solid foundation." 2 Dr. Bateman, in his 
 Historical Survey of the Diseases of London, states that " Dr. 
 Heberden has collected the most ample and satisfactory evidence of 
 the connection of the plague, and of the malignant contagious fever 
 which generally precedes and accompanies it (if, indeed, they be 
 not modifications of the same disease) with the filth of crowded, ill- 
 ventilated large cities, in all ages and countries." He then quotes 
 Dr. Heberden's remarks: " It has always originated and maintained 
 its head-quarters in the filthiest parts of those cities; as in St. Giles's, 
 
 1 Cowan's Vital Statistics of Glasgow, p. 26. 
 
 2 Hancock on Pestilence, p. 224. 
 
14 DAVIDSON ON THE CAUSES OP FEVER. 
 
 in London, in 1665, and in Whitechapel in 1626 and 1636; and in 
 those cities of Europe, which, from natural or political causes, have 
 been backward in adopting the improvements of modern times: the 
 picture of former manners is not exhibited in more lively colours 
 than that of former diseases. The plague visited Denmark in 1764, 
 it raged at Moscow in 1771, and at Cracow still later. The last- 
 mentioned town, Mr. Wraxall says, was not wholly paved till 
 within the last two years, and nothing can be so execrable as the 
 present paving, which scarcely deserves the name. There is not a 
 single lamp in the place ; no precautions are used to cleanse the 
 streets, which, of course, become infectious in summer and almost 
 impassable in winter." The following is Erasmus's description of 
 the habits of the English, about two centuries ago: " The floors are 
 commonly of clay, strewed with rushes, which are occasionally 
 renewed, but underneath lies unmolested an ancient collection of 
 beer, grease, fragments of fish, spittle, the excrement of dogs and 
 cats, and every thing that is nasty." 1 Dr. Hancock observes, that 
 most writers on the plague have remarked the exemption of Persia 
 from this disease, and he quotes the following passage from the City 
 Remembrancer : " The Persians, though their country is every 
 year surrounded by the plague, seldom suffer anything by it them- 
 selves; they are the most cleanly people in the world, many of 
 them making it a great part of their religion to remove filthiness 
 and nuisances of every kind from all places about their cities and 
 dwellings." 2 Drs. Barker and Cheyne, in their statement of the 
 circumstances which either preceded or attended the epidemic fever 
 in Ireland during the years 1816 and 1817, make the following 
 remarks, which may be assumed as conclusions drawn from the 
 reports of physicians practising in the various provinces, and from 
 the observation of more than 100,000 cases in general hospitals : 
 " When fever commenced in a poor family, or was introduced by a 
 stranger or lodger, it generally extended to all its members. The 
 poor were the chief sufferers, in consequence of their neglect of 
 cleanliness, particularly with respect to their clothing, and the 
 smallness and crowded state of their apartments; evils, at the time, 
 much increased by the extreme poverty which weighed them down. 
 On the other hand the superior classes, whose circumstances were 
 different, their clothing more frequently changed, their persons 
 more cleanly, their apartments less crowded and better ventilated, 
 and among whom seclusion from the sick was practised, in propor- 
 tion to their enjoyment of these advantages, generally escaped the 
 disease." 3 
 
 Dr. Bateman, after describing the methods to be adopted for pro- 
 moting cleanliness and sufficient ventilation, remarks: "If these 
 simple measures be steadily pursued, no confinement or accumula- 
 
 1 Bateman on the Diseases of London, p. 18. 
 
 2 Hancock on Pestilence, p. 287. 
 
 3 Barker and Cheyne on Fever, vol. i. p. 134. 
 
DAVIDSON ON THE CAUSES OF FEVER. 15 
 
 tion of morbid effluvia can take place under any state of fever; and 
 the air of the apartment may be breathed, and the bed and person 
 of the patient approached and touched with perfect impunity. If 
 this were not the case, indeed, physicians and nurses, especially 
 those employed in fever hospitals, would have little security for 
 their lives. During the fourteen years, in the course of which I 
 have almost daily been in contact with persons labouring under 
 contagious fever, not only myself but all the nurses have thus been 
 preserved from infection, with one exception, down to the period of 
 the present epidemic." He adds in a note : " It is no disparagement 
 to the system above described that some of the nurses and the 
 matron of the House of Recovery have been infected during the 
 present epidemic, which has kept the wards constantly full. The 
 impossibility of maintaining a free ventilation night and day, dur- 
 ing the cold weather, their perpetual exposure, in close contact, to 
 the breath and discharges of the patients, while feeding, moving, or 
 washing them, changing their beds and linen, and even stripping 
 off their infected clothes on admission, might be sufficient to coun- 
 teract the solitary operation of any general system, however effica- 
 cious. But the truth is, that the ventilation of the house has been 
 very imperfect, and even at the command of the nurses and patients ; 
 and the injurious consequences of this imperfection have become so 
 manifest, that the subject is now under the consideration of the 
 committee, while this work is in the press." 1 
 
 Dr. Hancock quotes the following facts, which illustrate very 
 powerfully the influence of ventilation : "In the year 1819, I had 
 occasion to see a very intelligent physician connected with one or 
 two fever hospitals in Dublin, during the epidemic, who assured 
 me he had seen no proof of the existence of contagion in the disease 
 (typhus) as it appeared in those institutions under his care, where 
 very great attention was paid to ventilation, and where the patients 
 were not inconveniently crowded. But soon after this, I saw 
 another physician no less intelligent, who informed me that in the 
 course of about four months, between 200 and 300 persons were 
 admitted into the Belfast Fever Hospital; and they were frequently 
 so crowded in the wards as nearly to cover the floor with their 
 beds ; in which case, although the building is new, airy, and well 
 regulated, the matron, twenty-two nurses, and the apothecary, took 
 the disease ; yet it was so mild, that scarcely more than one in fifty 
 died." 2 
 
 Dr. Prichard relates a striking example of the effects of a good as 
 well as of a deficient ventilation, which occurred in two of the 
 hospitals in Bristol, namely, St. Peter's and the Bristol Infirmary; 
 both of these institutions being under his medical superintendence. 
 " In the former, (St. Peter's,) the medical wards are very small, and 
 it was necessary to place the beds very near to each other, and to 
 
 ^ateman on Contagious Fever, p. 154. 
 2 Hancock on Pestilence, p. 339. 
 
16 DAVIDSON ON THE CAUSES OF FEVER. 
 
 put too great a number of patients in a given space. Offensive smells 
 were often perceptible ; and it was under these circumstances that 
 the disease was manifestly contagious." In the Bristol Infirmary the 
 wards are lofty and well ventilated. "Here, also, the fever patients 
 were dispersed among invalids of almost every other description. 
 But no instance occurred of the propagation of fever : none of the 
 nurses were attacked, nor were the patients lying in the adjacent 
 beds in any instance infected, though cases of the worst description 
 of typhus gravior were placed promiscuously among the other 
 patients, scarcely two feet of space intervening between the beds." 1 
 Drs. Barker and Cheyne state that "a remarkable proof was 
 afforded, in Sir Patrick Dunn's Hospital, of a ward, by the pecu- 
 liarity of its construction, protecting the attendants upon the sick 
 from the effects of contagion. The ward alluded to is the fever 
 ward for males, which extends the entire breadth of the left wing 
 of the hospital, being sixty-two feet by thirty-eight. It is twenty 
 feet high, and is subdivided by partitions, of the height of nine feet, 
 into six apartments, two of which are thirty-eight feet by sixteen, 
 and the rest are each nine feet square ; the latter contains, with 
 great convenience, four beds each, and the former ten ; but on 
 occasions of necessity, the square apartments have held five, and 
 the oblong twelve beds without inconvenience ; the partition walls 
 leave two passages, one leading from the door of the wards across 
 its breadth, and another passing in the middle of its length ; it is 
 furnished with three large fireplaces, two of which are in the ob- 
 long chambers, one on the north and the other on the south side of 
 the ward, and the third opposite the door, at the end of the passage 
 first described ; by this door, the fever-ward opens on the staircase, 
 which is walled and communicates with the corridors of the base- 
 ment and underground stories. The greater number of the win- 
 dows of the ward are sixteen feet from the floor, and in the ceiling 
 are placed two louvres, one toward either end, by means of which 
 and the fireplaces a brisk ventilation is kept up. During the late 
 epidemic, when Sir Patrick Dunn's Hospital, by agreement with 
 government, contained one hundred patients in fever, the male 
 ward was crowded, containing forty-four patients, yet only one 
 nurse was affected with fever: at the same period, the nurses in 
 attendance on the female patients, who were certainly not so much 
 crowded together, were continually taking the complaint, and gene- 
 rally had it with severity." 2 In addition to the facts which have 
 now been brought forward, it may be stated, without much chance 
 of contradiction, that, as there is in almost every large town defi- 
 cient accommodation for fever patients in an hospital during an 
 epidemic, overcrowding is an ordinary result, from the anxiety of 
 the directors to relieve the misery of the sick. The Glasgow 
 Fever Hospital is calculated to contain two hundred and twenty 
 
 1 Hancock on Pestilence. Prichard's History of the Fever in Bristol, p. 88. 
 2 Barker and Cheyne on Fever, vol. i. p. 488. 
 
DAVIDSON ON THE CAUSES OF FEVER. 17 
 
 patients ; and for nearly two years, namely, during 1836-7, it was 
 generally filled to its maximum, and frequently from ten to twenty 
 additional were accommodated. Now. it is quite obvious, that 
 such a large number of fever patients, all contained in one build- 
 ing, will exhale a prodigious quantity of typhoid effluvium, which 
 must be exceedingly concentrated; and that even the utmost clean- 
 liness, and the greatest degree of ventilation consistent with the 
 temperature that ought to be maintained, would scarcely be suffi- 
 cient for its proper dilution. 
 
 Drs. Barker and Cheyne remark, in that portion of their report 
 which has been already quoted, that typhus generally spreads in 
 the families of the lower classes, and very rarely in those of the 
 superior ranks. Dr. Cowan states that "the fever was chiefly, nay 
 almost wholly, confined to the labouring classes, and to the districts 
 which they inhabited, while among the wealthy and middle classes 
 of society it was comparatively seldom met with ; and when it did 
 occur, was not spread by contagion through all the inmates of the 
 family, as was usually the case among the families of the poor, but 
 was confined to a single individual." 1 These results, as stated by 
 the above-mentioned authors, agree, we are convinced, with those 
 which have been made in almost every other place. This remark- 
 able difference, in the two classes of persons referred to, must be 
 owing' chiefly to the wide diversity of circumstances in which they 
 are placed ; and approximates very closely to the difference which 
 exists between a crowded and consequently an ill-ventilated hos- 
 pital, and one which is limited to a small number of patients with 
 thorough ventilation. The lower classes in large cities generally 
 live in dirty, ill-ventilated houses, and are often filthy in their per- 
 sons ; while the better ranks live in more airy situations, have 
 larger houses, and are more attentive to cleanliness in their per- 
 sons and domestic habits; hence the effluvium which issues from a 
 typhus patient, in the first-mentioned situations, cannot be carried 
 off so readily, or diluted to the same extent with atmospheric air, 
 as in the second. But it may be said by the opponents of typhoid 
 contagion, that small-pox, measles, and scarlet fever, more fre- 
 quently spread in the families of the better ranks than typhus ; and 
 why is ventilation and dilution not effectual in these cases? In 
 answer to this objection, it may be stated, that these three last- 
 mentioned diseases are not equally contagious, and that scarlet 
 fever, particularly when it is not epidemic, is often confined to one 
 person in a family; whereas small-pox, in the majority of instances, 
 affects the greater number of unprotected persons, adults as well as 
 children. M. Rayer states that "scarlatina is contagious, but to a 
 less degree than measles. It affects chiefly children and young 
 persons, more rarely adults. Every individual is not, to the same 
 degree, apt to be affected with scarlatina, and every condition is 
 not equally proper for its development. It attacks females more 
 
 1 Cowan's Vital Statistics of Glasgow, p. 34. 
 3 — e 2 dav 
 
18 DAVIDSON ON THE CAUSES OF FEVER. 
 
 readily than males ; and some individuals, after having been exposed, 
 in vain, during many days to the contagion of this disease, have 
 been seized after the lapse of some time, in consequence of a simple 
 communication with persons who had visited patients affected with 
 this exanthema." 1 
 
 Dr. Bateman states that adults are not very susceptible of the 
 disease (scarlet fever), and that many medical practitioners who 
 have attended great number of patients affected with it, have never 
 experienced its effects. 2 
 
 Dr. Mason Good observes that "nothing is more common than 
 for a sporadic case of rosalia (scarlatina) to occur in a family with- 
 out communication of itself to the surrounding children, although 
 no pains may have been taken to keep them separate ; while a few 
 months afterwards it may possibly be received from a neighbour's 
 house, merely by an accidental visit for a few minutes. In the one 
 case, there was no predisposition in the habit to receive the com- 
 plaint; in the other, the altered state of the atmosphere has, per- 
 haps, produced such a predisposition in a very high degree, and 
 prepared the way for the disease to become a very general epidemic. 
 What this peculiar state of the atmosphere is, has not been very 
 accurately ascertained." 3 Now, although it be granted that clean- 
 liness and ventilation have somewhat less effect in preventing the 
 spread of small-pox, measles, and scarlet fever, than in checking 
 the progress of typhus ; it has been shown by the above quotations 
 that these diseases differ from one another in points equally mate- 
 rial. It follows, therefore, that scarlet fever is regulated by a law 
 similar to that of typhus, in being little contagious under certain 
 circumstances ; and that though cleanliness and ventilation may 
 not prove an antidote equally efficacious to the contagion of small- 
 pox, measles, and scarlet fever, as to that of typhus, yet to exclude 
 the latter from the class of contagious fevers from this circumstance, 
 would involve also the exclusion of scarlatina for an equally strong 
 reason. In reasoning upon this subject, it does not seem difficult 
 to conceive that one species of effluvium may be harmless, if 
 diluted with a certain proportion of atmospheric air, while another 
 may retain its virulency under similar circumstances; or that one 
 species of effluvium may adhere with tenacity to every kind of 
 clothing, while another is absorbed most readily by filthy gar- 
 ments, or by the deposits which are formed on the skin of an un- 
 cleanly person. We are in possession of no experiments which 
 tend to prove such an opinion ; but there is one analogy which 
 will occur to every medical practitioner in vaccination. It is well 
 known that if too much blood be drawn during the process of vac- 
 cination, the effect is very frequently prevented ; and this is always 
 explained on the principle, that the vaccine virus is diluted too 
 
 1 Rayer des Maladies de la Peau, torn. i. p. 63. 
 
 2 Bateman on Cutaneous Diseases, p. 70. 
 
 3 Good's Study of Medicine by Cooper, vol. iii. p. 19. 
 
DAVIDSON ON THE CAUSES OF FEVER. 19 
 
 much with the blood, as the same result follows when it is mixed 
 with water. We have many analogies among the gases, such as 
 carbonic acid, carburetted hydrogen, &c, to prove not only that 
 when diluted to a certain extent with atmospheric air they may be 
 respired with safety, but that each gas has its own peculiar law 
 respecting the requisite proportion of dilution that is required for 
 that purpose. 
 
 The majority of French physicians are of opinion that typhoid 
 fever is not contagious, and this belief was almost universal until 
 M. Bretonneau published a contrary opinion. The following quo- 
 tation from M. Chomel will perhaps account, to a certain extent, 
 for the opinions of the French physicians on this subject: — "An- 
 other circumstance contributes with us to render the transmission 
 of a contagious malady difficult, particularly the typhoid disease, 
 that in our hospitals every thing connected with cleanliness and 
 ventilation is in the most perfect condition, and that the typhoid 
 patients are never united, either in the same establishment or in 
 the same ward, while their number is always very small, when 
 compared with the number of those affected with other diseases; 
 so that none of the conditions are present which favour contagion. 
 It is the same wittrsmall-pox, and no one disputes its contagious 
 character. In the wards of our hospitals, there are persons fre- 
 quently affected with small-pox, and there are often individuals 
 who have not been vaccinated, or who, not having undergone 
 variola, are susceptible of contracting the disease ; yet few in- 
 stances of its transmission are evident. It is also very rare that the 
 transmission of measles or scarlet fever from one subject to another, 
 in the Hopital des Enfans de Paris, can be verified, which even 
 presents in some circumstances the most favourable conditions for 
 the transmission of these diseases." 1 At page 98, some tables are 
 given which tend to show the connection of filthy habits with 
 typhus contagion. 
 
 2. Typhus generally attacks individuals only once during their 
 lives. — The second law of contagious fevers is that they only affect 
 persons once during their lives. 
 
 We believe this law to be completely established, and though 
 there are instances of small-pox, measles, and scarlet fever affecting 
 individuals more than once in their lives, yet these may fairly be 
 considered only as exceptions to the general rule. 
 
 Before bringing forward the facts upon which the claims of 
 typhus to be comprehended under this law may be founded, it is 
 necessary to state that the evidence is by no means so clear and 
 satisfactory as it is in small-pox, measles, and scarlet fever. These 
 three last-mentioned diseases cannot, in the present day, be readily 
 confounded with any other ; for their diagnostic marks are very 
 precise and definite ; while the several kinds of continued fever 
 have hitherto not been accurately ascertained, and have sometimes 
 
 1 Chomelj Legons de Clinique Medicale, torn. i. p. 321. 
 
 2* 
 
20 DAVIDSON ON THE CAUSES OF FEVER. 
 
 been considered merely as varieties of typhus ; hence the difficulty 
 of establishing- the application of this law to any one of them. We 
 hope, however, it will appear from the quotations which shall pre- 
 sently be adduced, that the approximation of typhus to this law is 
 so near as to preclude, in all fairness, its exclusion. M. Chomel, 
 after remarking upon the number of persons that are seized more 
 than once with pneumonia, states that "In the typhoid fever, on 
 the contrary, notwithstanding the care with which the patients had 
 always been interrogated on this point, no one, among one hundred 
 and thirty persons who had been received at the Clinique affected 
 with the disease, gave such a statement as could lead to the pre- 
 sumption that he had ever before laboured under it; on the con- 
 trary, most of them asserted that it was the first time they had 
 been ill." 1 He elsewhere adds: : 'We have already stated that the 
 typhoid fever, in ordinary circumstances, affects the same indivi- 
 dual only once. This is the result of all the facts hitherto col- 
 lected. Since we began to make special researches and conclu- 
 sions respecting this disease, no authentic example to the contrary 
 has been observed, although the number of cases which are observed 
 be very considerable, and examples of its return ought to be met 
 with, if the malady were susceptible of being reproduced many times 
 in the same person." 
 
 In interrogating our patients, we have always taken care to turn 
 their attention from this quarter, but they have never answered in 
 such a manner as to induce us to believe that they had laboured 
 under the same disease ; and after all, though some contrary facts 
 should be met with in so frequent a malady, these exceptions, 
 which are little numerous, are nothing extraordinary, and do not 
 overthrow the species of law which has been announced. Small- 
 pox, scarlet fever, measles, which most generally attack the same 
 individual only once, sometimes return, especially during epidemics 
 of these diseases ; it will not be more astonishing if some examples 
 of a return of the typhoid affection be met with. This circum- 
 stance is, then, a very important fact, for there are only a small 
 number of diseases that attack the same individual only once, and 
 amongst these maladies, there is none which is not evidently con- 
 tagious ; the typhoid fever will, then, be the only exception to this 
 kind of law, if it be not contagious like the diseases with which it 
 has this important point of agreement. In the mean time we ought 
 to observe that, though all the diseases which attack the same per- 
 son only once are contagious, it does not follow that all those that 
 are transmitted from one individual to another attack only once, 
 many among them, as syphilis and the itch, are reproduced indefi- 
 nitely." 2 
 
 Dr. Lombard, of Geneva, when describing the difference between 
 the continental and British typhus, states that "in one remarkable 
 
 1 Chomel, Lefjons de Clinique Medicale, torn. i. p. 309. 
 8 Ibid, p. 333. 
 
DAVIDSON ON THE CAUSES OF FEVER. 21 
 
 point, however, I believe they agree, I mean the fact that no one 
 is known, or at least is very rarely known, to have the eruptive 
 typhus twice. With us such instances are scarcely if ever met 
 with, and I am informed that with you a person once attacked with 
 typhus, attended with the measles like eruption, may safely calcu- 
 late upon immunity from the disease for the future." 1 
 
 Dr. Perry, of Glasgow, states as one of his conclusions respect- 
 ing typhus fever, that " contagious typhus is an exanthematous 
 disease, and, like smallpox, measles, and scarlet fever, during its 
 course produces some change on the system, by which the indi- 
 vidual having once undergone the disease is (as a general rule) 
 secured against a second attack, and may with impunity expose 
 himself to the contagion of typhus, if he continues to reside in the 
 same country in which he previously had the disease. In those 
 cases which are exceptions to the general rule, the disease appears 
 in a mild and modified form, the crisis taking place on the seventh, 
 ninth, or eleventh day." The same author states that this conclu- 
 sion as well as the others in his paper are " the result of careful 
 observation in upwards of 4000 cases." 2 Drs. Barker and Cheyne, 
 who had the most extensive opportunities of ascertaining the his- 
 tory of typhus, seem to entertain opinions similar to those already 
 quoted. They state that "at the hospital in Cork street, only one 
 physician and the apothecary had an attack of fever ; but then most 
 of the physicians of the establishment had laboured under that dis- 
 ease on some former occasion previous to the appearance of the 
 epidemic." 3 Dr. Cowan, as already quoted, states that all the gen- 
 tlemen who have acted as clerks in the Fever Hospital for many 
 years past have been attacked with fever unless they had it previ- 
 ously to their election. 
 
 Hildenbrand's opinion on this subject is of a more modified kind. 
 He states that "the miasma of typhus, after having produced the 
 fever, destroys almost always for a certain time the susceptibility 
 to a similar contagion ; nevertheless, it destroys it rarely for the 
 whole of life, as does smallpox, measles, (fee. It has, however, 
 under this resemblance some analogy with the virus of these dis- 
 eases, whilst on the contrary it totally differs from the syphilitic 
 virus, which when once introduced into the human body, always 
 favours more and more a similar contagion." 4 
 
 The following table shows the answers, to questions which were 
 carefully put to patients who were admitted into the Glasgow 
 Fever Hospital from November 1st, 1838, to November 1st, 1839. 
 It includes the whole of the patients affected with eruptive typhus, 
 from whom answers were obtained relative to any former affection 
 with fever, as evidence from decided cases only could be made 
 available in the elucidation of this point: 
 
 1 Dublin Journal of Medical Science, vol. x. p. 22. 
 
 2 Edinb. Med. and Surgical Journal, vol. xlv. p. 67. 
 
 3 Barker and Cheyne on Fever, vol. i. p. 135. 
 
 4 Hildenbrand, de Typhus contagiera^par J. C. Gasc, p. 118. 
 
22 DAVIDSON ON THE CAUSES OF FEVER. 
 
 Not previously affected . . . 
 Previously affected .... 
 
 Males. 
 
 Females. 
 
 Total. 
 
 284 
 33 
 
 251 
 41 
 
 535 
 
 74 
 
 609 
 
 This table shows that out of 609 eruptive or decided cases of 
 typhus there were only 74 persons who stated that they had pre- 
 viously laboured under fever. This part of the evidence may be 
 reckoned positive ; for individuals of all intellectual capacities re- 
 member a remarkable circumstance of this kind. On the other 
 hand, the evidence respecting the nature of the former fever or 
 affection is the converse of this ; for only in a very few cases can it 
 be correctly ascertained ; and when we take into account the vari- 
 ous diseases which are confounded with typhus (as shall be after- 
 wards shown,) such as bronchitis, pneumonia, pleurisy, intestinal 
 affections, febriculous or short fevers, and the numerous ailments 
 of childhood, this small number can be satisfactorily accounted for. 
 
 It appears, therefore, that the evidence which can be produced to 
 bear on this point, although not very extensive, decidedly supports 
 the opinion that eruptive typhus fever affects individuals as a gene- 
 ral rule only once in their lives ; and it is to a considerable extent 
 corroborative of this opinion, that almost all the clerks and nurses 
 of the Glasgow Fever Hospital for the last six or seven years have 
 had typhus characterised by the eruption, and not one of them, as 
 far as we have been able to learn, have ever had it since ; while 
 almost all of them consider themselves now perfectly secure against 
 a second attack, although constantly exposed to the effluvia arising 
 from fever patients. 
 
 3. Typhus is characterised by an exanthematous eruption. 
 The third characteristic of the contagious exanthemata is an erup- 
 tion which has a regular rise, progress, and decline. The exan- 
 thematous eruption or rash which is peculiar to typhus fever has 
 only been accurately attended to within these few years as a diag- 
 nostic symptom. It was, however, noticed by Rogers, in the fever 
 which prevailed in Ireland during the year 1731, and one of the 
 characteristic symptoms is described as "a universal efflorescence 
 of petechia? ;' n also by Huxham in 1734-5, Sir John Pringle in 
 1750, &c. 
 
 No particular conclusion can be drawn from these authors' ac- 
 count of it ; but when taken along with their general description 
 of the disease, the opinion is corroborated that it was the very same 
 affection that is so characterised at the present day. Hildenbrand 
 described it in 1806 more particularly than any previous author. 
 He states that it makes its appearance about the fourth day of the 
 disease on the breast, loins, back, thighs, and arms, as being more 
 warm, but sometimes on the face; that it is so much more abun- 
 
 1 Barker and Cheyne on Fever, vol. i. p. 4. 
 
DAVIDSON ON THE CAUSES OF FEVER. 23 
 
 dant as the eyes are red. He also remarks that petechia? may exist 
 with or without the eruption, are not indispensable phenomena, 
 and are only developed in certain conditions. He farther observes 
 that the exantheme is sometimes not present in those cases of 
 typhus which are irregular in their progress. 1 The typhoid erup- 
 tion was also a very general characteristic of the epidemic fever 
 which prevailed in Ireland during the years 1817-18-19. Dr. 
 Bracken makes the following statement : " Of about 250 cases 
 which fell under my care in November and December of that year, 
 the majority had eruptions of spots of various appearance as to size, 
 shape, and colour. They were generally of a diffused appearance, 
 gradually shading off, and insensibly disappearing, and of the size 
 of a grain of hemp-seed, but sometimes much larger or much 
 smaller. The distinct, well-defined petechia? were frequently seen 
 of a bright brown or purple colour. The shoulders seemed to be 
 more frequently affected by these eruptions, but the whole surface 
 of the body was often covered by them." 2 Drs. Barker and Cheyne 
 give the following account of the eruption, as deduced from reports 
 received from several parts of Munster : "As the disease advanced 
 it was observed in most or all parts of the province that eruptions 
 of different kinds, either closely allied to or varieties of those termed 
 petechial, very generally accompanied it. In some instances the 
 eruption was papular, or a motley appearance of the skin, or a rash 
 somewhat resembling measles showed itself. At Cork, Dr. M. 
 Barry remarked that in the species of fever which he terms syno- 
 chus, petechia? seldom occurred earlier than the fourth or fifth day ; 
 but his observation, if it does not express it directly, at least im- 
 plies that their occurrence was frequent. They were generally of 
 a bright red colour, sometimes small, at other times large. He did 
 not consider them dangerous, nor find it necessary to abstain from 
 those measures of depletion which were useful when high excite- 
 ment prevailed. In a communication from Clonmell, Dr. Fitz- 
 gerald states that petechias occurred in four cases out of five. At 
 Listowel, petechia? was so common that Dr. O'Connell did not see 
 six cases of fever unattended by a petechial eruption, which often 
 appeared early in the disease." In the account of Connaught, the 
 same authors state that "an early eruption of petechia?, which 
 were often to be observed on the third or fourth day or even earlier, 
 and were visible for four or five days, was a general symptom of 
 the disease ; when petechia? appeared thus early, they were not 
 indicative of any malignancy." In the report for Ulster, it is stated 
 that petechial eruptions were very common and that they occurred 
 early. For Leinster, the same reporters state that one physician 
 observed the petechia? in seven cases out often, some thought them 
 more general than they had been on any former occasion, and 
 others represented them as universal. They appeared on the third, 
 
 1 Hildenbrand, de Typhus contagieux, par J. C. Gasc, p. 53-4. 
 
 2 Barker and Cheyne on Fever, vol. ii. p. 231. 
 
24 DAVIDSON ON THE CAUSES OF FEVER. 
 
 fourth, or fifth days, continued visible for four or five days, and 
 were often remarked in the mildest cases. 1 
 
 The typhoid eruption, however, excited very little attention 
 among the authors who wrote upon the epidemic that prevailed in 
 Britain about the same period as in Ireland; and even up to a much 
 later period it is only noticed in a cursory manner in our treatises 
 on fever, and not as a diagnostic mark of great value. Dr. Alison 
 in 1827 described it as a very frequent symptom of the epidemic 
 which prevailed in Edinburgh about that period, occurring in a 
 majority of the cases, and remarked that these eruptive fevers 
 formed the connecting link between continued fever and the con- 
 tagious exanthemata. 2 
 
 M. Louis, who published his admirable work on gastro-enteritis 
 or typhoid fever in 1829, states that " he has observed this eruption 
 in twenty-six out of thirty-five cases, where it has been searched 
 after, without saying that' it was not present in some others ; many 
 of the persons in whom it was present had come to the hospital 
 after the twenty-fourth day of the disease, at a period when the 
 spots had perhaps disappeared." 3 M. Chomel gives the following 
 excellent description of the typhoid eruption : "Usually from the 
 seventh to the ninth day the eruption peculiar to typhoid fever 
 makes its appearance, which consists in minute rose-red spots, dis- 
 appearing on pressure from half a line to two lines in diameter, of 
 a circular form, without elevation or scarcely raised above the 
 level of the skin, dispersed over the abdomen, sometimes on the 
 chest, less frequently on the thighs, the arms, and forearms. These 
 little spots are so much the more distinct as the skin is white; in 
 persons who have brown skins they are sometimes distinguished 
 with difficulty. Their number cannot be determined because they 
 are not all equally apparent ; but in order to furnish a character- 
 istic of the typhoid affection they ought at least to be from fifteen 
 to twenty. When there are only two or three, no value can be 
 attached to their presence. The eruption does not make its ap- 
 pearance on all points at once ; often, after having noticed for three 
 or four days some rose-coloured spots upon the abdomen, but in too 
 small number to be considered as important, they are found all at 
 once very numerous upon the chest and belly, sometimes upon the 
 thighs, the arms, the back, and even the face, though very rarely. 
 Its duration is not always the same ; in some cases, after two or 
 three days, there is no vestige of it ; at other times it persists during 
 twelve or fifteen : but in the latter case it consists of many succes- 
 sive eruptions ; for each rose-coloured spot is usually visible for 
 three or four days only, and sometimes less; and at the end of this 
 time it disappears altogether, after having attained a colour less 
 vivid. These spots present, at most, a slight elevation on the sur- 
 
 1 Barker and Cheyne on Fever, vol. i. pp. 426, 454, 465, and 483. 
 
 2 Edinb. Med. and Surgical Journal, vol. xxviii. 
 
 3 Louis, de Gastro-Enterite, torn. ii. p. 231. 
 
ing 
 
 DAVIDSON ON THE CAUSES OF FEVER. 25 
 
 face of the skin, but they never have a conical form or vesicles at 
 their apex. They rarely appear before the eighth day after the 
 invasion of the disease. The following are the results of observa- 
 tions collected in our wards during the years 1830-1-2. Among 
 seventy cases of typhoid fever, where the presence or absence of 
 rose-coloured lenticular spots was carefully established, in sixteen 
 cases, at no period of the disease could traces of this eruption be 
 found ; from which it may be inferred that in about one fourth of 
 the persons seized with the typhoid affection this eruption is want- 
 
 Chomel found that among fifty-four cases none presented the 
 eruption before the sixth day, and in two it appeared after the 
 thirty-sixth. This, he states, is confirmed by the observation of 
 M. Louis, which were made on a much larger number of patients. 
 He attaches great value to the eruption, as a diagnostic mark of 
 typhoid fever, as it is as rare in other acute diseases as it is com- 
 mou in this. 
 
 Dr. Roupell states that in St. Bartholomew's Hospital, London, 
 the eruption in typhus occurs in seventy out of every 100 cases. 2 
 Dr. West, in his account of the typhus exantbematicus as observed 
 in St. Bartholomew's Hospital, states that " forty-two cases pre- 
 sented the peculiar measle-like eruption described by so many 
 authors, which in all those cases in which I have been able accu- 
 rately to note the date of its appearance, first showed itself from the 
 sixth to the eighth day, generally on the former. It appeared in 
 one instance on the fourth and another time on the fifth day; but 
 I never saw it make its first appearance after the eighth day, though 
 it was still visible on several patients admitted on the fourteenth, 
 and on three who came to the hospital on the twenty-first day of 
 the affection. Of the eighteen cases in which no eruption was 
 observed, five only were admitted before the eighth day of the dis- 
 ease ; it is, therefore, very probable that the eruption had existed 
 in some of these patients but had disappeared before their admis- 
 sion." 3 Dr. Cowan has investigated the frequency of the eruption 
 in the Glasgow Fever Hospital on upwards of 2000 cases, during 
 the year 1835-6 ; and his results are the following: (: At the close 
 of the year, in 76-16 per cent, of the males, and 71-77 of the females, 
 the typhoid eruption had occurred, giving as an average of the 
 whole cases 7399 out of every 100 admitted." 4 
 
 Dr. Craigie found the typhoid eruption only in seventy-nine 
 among 3 69 cases in the Edinburgh Royal Infirmary; 5 while Dr. 
 Henderson discovered it in 108 cases out of 130 in the same insti- 
 tution at a subsequent period. 6 
 
 1 Chomel, Lecons de Clinique Medicale, torn. i. p. 18. 
 
 2 Roupell on Typhus, p. 35, 1838. 
 
 3 Edinburgh Medical and Surgical Journal, July, 1838, p. 140. 
 
 4 Cowan's Vital Statistics of Glasgow, p. 26. 
 
 6 Edinburgh Medical and Surgical Journal, vol. xxvii. p. 301. 
 
 6 Ibid. October, 1839, p. 437. 
 
26 
 
 DAVIDSON ON THE CAUSES OP FEVER. 
 
 In the Glasgow Fever Hospital, from May 1st to Nov. 1st, 1839, 
 during- which time the presence or absence of eruption was care- 
 fully noted, the proportion was as follows : 
 
 Cases without Eruption or doubtful 
 
 Males. 
 
 Females- 
 
 Total. 
 
 224 
 130 
 
 217 
 120 
 
 441 
 250 
 
 691 
 
 This table includes every case, with the exception of smallpox, 
 measles, hooping-cough, and scarlet fever. 
 
 Dr. Peebles, in 1835, gave a very minute and excellent account 
 of exanthematous typhus, and states, as the result of a minute 
 inquiry into the subject in Great Britain and on the continent, that 
 " he has found the eruption as constant as any exanthema of other 
 eruptive diseases." 1 
 
 It appears, therefore, that the eruption is present generally in 
 from 70 to 75 out of every 100 patients that are admitted into fever 
 hospitals in this country as well as in France. It must be well 
 known, however, to every hospital physician, that cases are fre- 
 quently admitted as continued fever, that are found, on examina- 
 tion, to be other diseases, and which are usually included in the 
 total enumeration ; but this point shall be further illustrated in 
 another part of the essay. 
 
 It is also well known that many cases of fever are admitted at a 
 very late stage of the disease, as may be proved by statistical tables 
 and also from the great number of deaths that occur on the first, 
 seeond, and third days after admission ; hence it is extremely 
 probable that the eruption has disappeared in a certain proportion 
 of those who have the other decided symptoms of typhus. There 
 is one fact, however, which powerfully supports the opinion that 
 contagious typhus, in the great majority of cases, particularly in 
 adults, is attended with the eruption, namely, that almost all the 
 instances of fever which have occurred during the last six or seven 
 years among the physicians, clerks, nurses, &c. of the Glasgow 
 Fever Hospital, have been accompanied with this exanthema. We 
 have made careful inquiries respecting this point, and have only 
 heard of one or two exceptions amongst at least 100 cases. We do 
 not, however, mean to maintain that typhus fever cannot exist with- 
 out the presence of this eruption ; on the contrary, we have repeat- 
 edly attended families where the majority only of those affected 
 were so characterised, and we have remarked this two or three 
 times, when several of a family were sent into the hospital. 
 
 The want of regularity in the appearance of the eruption, and 
 its persistency in regard to time, has been considered opposed in 
 analogy to that of smallpox, measles, and scarlet fever; and cer- 
 
 1 Edinburgh Medical and Surgical Journal, vol. xliv. p. 373. 
 
DAVIDSON ON THE CAUSES OF FEVER. 27 
 
 tainly, though these three diseases are more regular in their charac- 
 teristic eruption than typhus, yet in scarlatina anginosa the eruption 
 is frequently irregular or altogether absent. Dr. Tweedie, who 
 must have treated scarlet fever extensively in the London Fever 
 Hospital, makes the following statement : " Indeed, we are inclined, 
 from our own experience, to affirm that the scarlatina simplex, 
 scarlatina anginosa, and the scarlatina or angina maligna, and the 
 sore throat without efflorescence on the skin, are merely varieties of 
 one and the same disease." 1 He also quotes the results of Dr. 
 Willan's experience during an epidemic scarlatina in the year 
 1786. " Of 251 cases, there were 152 of scarlatina anginosa, forty- 
 two of sore throats without eruption on the skin, and thirty-nine of 
 scarlatina maligna." 2 Rayer states that u often it does not appear 
 until the third day, and is not dispersed so constantly upon the 
 
 whole surface of the body It is sometimes entirely effaced 
 
 on the day of its appearance, and is developed anew at a period 
 
 more or less near The appearance of the exanthema is 
 
 tardy; its tint is feeble and livid; it is interspersed with petechiae, 
 and its duration is uncertain. It appears and disappears many 
 times." 3 It appears, therefore, that scarlet fever often differs from 
 smallpox very materially in the regularity of its eruption ; for that 
 of the latter disease is extremely regular and almost unvarying in 
 its rise, progress, and decline; while in the former it is frequently 
 absent, and in other cases so evanescent as not to be distinctly 
 recognised. The eruption characteristic of typhus again differs 
 from that of scarlet fever, in being still less regular than it; but 
 there is not a greater difference, if there be not less, in this respect, 
 between scarlet fever and typhus than there is between scarlet fever 
 and smallpox. 
 
 4. Typhus cannot be checked in limine. It has also been stated 
 by authors, and it is a prevalent opinion among medical prac- 
 titioners, that typhus can be checked in its early stages, and that in 
 this respect its law is totally different from the exanthematous 
 fevers. If this opinion were correct, the analogy between these 
 affections and typhus would be greatly diminished, though not 
 completely undermined; for it is not contrary to experience to sup- 
 pose that some agent may be discovered that might be capable of 
 modifying or destroying the poisonous principle that is lodged in 
 the body. Those, however, who believe in the possibility of check- 
 ing typhus in limine, have assumed a false premise, at least one 
 which is not admitted, from which they draw their conclusions, 
 namely, that every febrile affection which resembles this disease in 
 its early symptoms is identical with it. Now it is well known to 
 every medical practitioner that many of those febrile attacks which 
 arise from disturbance of the digestive functions and from vicissi- 
 tudes of temperature are attended with the same symptoms as 
 
 1 Cyclopaedia of Practical Medicine, vol. iii. p. 647. 2 Ibid., p. 653. 
 3 Rayer, Traite de Maladies de la Peau, torn. i. pp. 59, 60. 
 
28 DAVIDSON ON THE CAUSES OF FEVER. 
 
 typhus in its early stages ; and yet they will subside in a few days 
 under every variety of treatment, and frequently without any treat- 
 ment at all, at least such as could produce any effect on the system. 
 If typhus fever, which is frequently so prevalent, could be checked 
 in its progress by the means which are generally employed for that 
 purpose, namely, bleeding, purging, sweating, &c, this doctrine 
 would long ere now have been established with the same certainty 
 as that peritonitis or pneumonia can be checked by a similar sys- 
 tem of treatment; and yet the disease proceeds onwards in its 
 course, unrestrained by the heroic but occasionally injudicious 
 attempts to arrest it. If, then, there be febrile affections which sub- 
 side in a few days under every variety of treatment, and often with- 
 out any possessing a curative operation, it follows that those who 
 make the assertion that they can check typhus in limine, should 
 prove that their cases did not belong to the febriculse we have 
 referred to; or what would amount to the same thing, make their 
 experiments upon an unequivocal example of the disease, namely, 
 one characterised by the eruption, and demonstrate that they can 
 stop its career. 
 
 Crisis of typhus is pretty regular in cases not complicated. A 
 second objection has been brought forward against the inclusion of 
 typhus among exanthematous fevers, namely, that it has no regular 
 crisis like these last-mentioned diseases. This objection does not 
 seem to have much weight attached to it; and to give it any degree 
 of importance, it would be necessary to prove that all the other 
 fevers of this order are uniformly characterised by a crisis on a 
 particular day. Now, what are the facts connected with the history 
 of this point in scarlet fever. Dr. Bateman states that the rash in 
 scarlatina anginosa does not always appear on the second day, as 
 in scarlatina simplex, but not unfrequently on the third; nor does 
 it so constantly extend over the whole surface, but comes out in 
 scattered patches, which seldom fail to appear about the elbows. 
 Sometimes, too, it vanishes the day after its appearance, and reap- 
 pears partially at uncertain times, but without any corresponding 
 changes in the general disorder; the whole duration of the com- 
 plaint is thus lengthened and the desquamation is less regular 
 
 The same author, after describing the dangers which result from 
 hemorrhage, diarrhoea, &c, in malignant scarlatina, states that 
 " even those who escape through these dangers have often to 
 struggle against many distressing symptoms for a considerable 
 length of time, such as ulcerations spreading from the throat to the 
 contiguous parts, suppuration of the glands, tedious cough and 
 dyspnoea, excoriations about the nates, (fee, with hectic fever." 1 
 When treating of measles, Rayer remarks that "it is never the 
 exantheme which compromises life. The gravity of the evil de- 
 pends upon the internal inflammation which accompany or succeed 
 it. — The appearance of the measles before the third day, the sudden 
 
 1 Bateman on Cutaneous Diseases, pp. 73 and 85. 
 
DAVIDSON ON THE CAUSES OP FEVER. 29 
 
 disappearance or the leaden redness of the spots, the appearance ot 
 petechias, much difficulty of breathing, are severe symptoms. They 
 are often characteristics of bronchitis and pneumonia, the existence 
 of which is easily ascertained by auscultation and percussion of the 
 chest When the symptoms of gastro-pulmonary inflamma- 
 tions, which accompany the exantheme of measles, are little intense, 
 and when it travels over its periods easily and regularly^ the treat- 
 ment of the disease is very simple." 1 It is obvious from these quota- 
 tions, and it is well known to every experienced practitioner, that 
 the crisis of measles and scarlet fever varies considerably in different 
 individuals, being pretty regular and early in the simple cases, and 
 more or less protracted and irregular in those that are complicated 
 with any organic affection. In typhus fever, uncomplicated with 
 any serious organic disease of the head, chest, or abdomen, the 
 crisis occurs very frequently about the same period in persons of a 
 similar age; for young persons, as a general rule, pass through the 
 disease more quickly than those more advanced in life. 
 
 Chomel states that the crisis or amelioration of the symptoms in 
 sixty-eight cases, occurred in fifty, or in about three out of four, 
 from the fifteenth to the thirtieth day. 2 Dr. Arthur Thomson states 
 that the average duration of 2630 cases was twenty-seven days; 
 and this calculation was made from cases described and enumerated 
 in the works and papers of Drs. Bateman, Welsh, S. Smith, Latham, 
 and Craigie. 3 There is certainly considerable irregularity as to the 
 period when the crisis takes place in typhus in different individuals ; 
 at the same time, it may be remarked that a majority of patients 
 begin to ameliorate within a certain period, and the reports from 
 the various authors already quoted in regard to this point do not 
 differ very materially as to the mean duration of fever, showing, 
 even with imperfect statistics, a near approximation to some law by 
 which it is regulated. It ought to be observed, however, that the 
 evidence obtained from public hospitals is still very uncertain; for 
 unless very careful and repeated inquiries be made to the patient, 
 no satisfactory or accurate answer can be obtained, as to the period 
 when the disease commenced; for he is often partially incoherent, 
 and, in almost all cases, more or less confused in his ideas; and 
 even though there be. an opportunity of questioning his friends, 
 more or less of cross-examination is generally required to elicit a 
 correct answer. 
 
 A degree of uncertainty also arises from not calculating the crisis 
 always at the same period. Some, as Chomel, Mills, Stoker, &c., 
 calculating the termination of the disease from the commencement 
 of the convalescent stage ; while others have included the whole 
 period of the patient's residence in the hospital in its duration. It 
 is obvious that great discrepancy must arise from such a different 
 
 1 Rayer, Traite des Maladies de la Peau, p. 24. 
 
 "Chomel, Legons de Clinique Medicale, vol. i. p. 44. 
 
 3 Edinburgh Medical and Surgical Journal, July, 1838, p. 109. 
 
30 DAVIDSON ON THE CAUSES OP FEVER. 
 
 method of calculation ; for a patient is often a week and sometimes 
 two weeks in an hospital after the period of convalescence com- 
 mences. Another uncertainty on this point has arisen from not 
 classifying patients according to their different ages, such as is 
 employed in calculating the mortality of typhus at the different 
 periods of life ; for if the disease be shorter in its duration, as it 
 certainly is, in young persons than in those more advanced in life, 
 it is impossible to expect uniformity by arranging the whole to- 
 gether. It would also contribute to elucidate this point, were the 
 duration of the undoubted cases, namely, those characterised by the 
 eruption, classified separately; as by this means, the duration of 
 typhus would not be confounded with that of other continued 
 fevers, and this method might also be made available as one of the 
 means of diagnosis. 
 
 The very frequent complications of typhus with organic affec- 
 tions in the different cavities of the body is another reason amply 
 sufficient to account for a considerable portion of its irregularity as 
 to termination ; and as these complications occur more frequently 
 in this disease than in smallpox, measles, and scarlet fever, it follows 
 that allowance should be made for its greater irregularity on these 
 accounts; as it has already been shown by quotations from authors 
 that some of the exanthematous fevers are also rendered irregular 
 and protracted by organic complications. 
 
 Dr. Arthur Thomson gives the following table of the complica- 
 tions of fever compiled from cases related by Drs. Smith, Tweedie, 
 Alison, and Craigie, and it shows that the complicated varieties are 
 much more numerous than the simple or uncomplicated. 
 
 Simple fever .... 
 
 374 
 
 Fever with cerebral complications 
 
 375 
 
 thoracic do. . 
 
 264 
 
 abdominal do. . 
 
 180 
 
 mixed do. . 
 
 308 
 
 1501 
 
 5. Relapses in typhus do not occur after complete convalescence, 
 unless some local disease be present. The occurrence of relapses 
 in fever is also brought forward as an important difference between 
 it and the contagious exanthemata ; and almost every author who 
 has written on this subject mentions them as more or less frequent 
 at different periods and during different epidemics. They do not 
 seem to occur frequently in the typhoid fever, for Chomel does not 
 make any particular reference to this point ; and he merely states 
 that the convalescence is sometimes prolonged, and that trouble- 
 some results are sometimes the consequence of satisfying hunger. 
 
 In considering this subject it is necessary, however, to observe 
 that relapses, according to most authors, do not mean a return of 
 the fever after complete convalescence, but a return of the symp- 
 toms with their former intensity, after a partial recovery, or what 
 in the majority of cases might more properly be called a remission 
 of the disease ; for it is perfectly obvious that if the febrile symp- 
 
DAVIDSON ON THE CAUSES OP FEVER. 
 
 31 
 
 toms had only been meliorated, but not removed, that the disease 
 was still present in the system. 
 
 That relapses do occur, in a small proportion of the continued 
 fevers of this country, after complete convalescence, we have no 
 manner of doubt; but certainly this occurrence is rare in typhus, 
 without the co-existence of some organic lesion sufficient to account 
 for the return of the febrile symptoms. A considerable number of 
 what are generally called relapses, particularly during the preva- 
 lence of an epidemic, consist of cases which have been admitted 
 with fevers not of a typhoid kind, such as febricula, bronchitis, and 
 those arising from gastric or intestinal derangement ; and have 
 caught the contagion of typhus during their residence in the hos- 
 pital. That, this occurs, as a general rule, in the fever hospitals of 
 this country we are not in possession of facts to prove ; but that it 
 has very frequently occurred in the Glasgow Fever Hospital there 
 can be no doubt ; and during the late epidemic it was considered 
 very dangerous to retain a patient long in the house after his con- 
 valescence from a febricnlous affection. 
 
 The following table shows the number of relapses or secondary 
 affections that occurred after complete convalescence among 686 
 cases, admitted into the Glasgow Fever Hospital from May 1st to 
 November 1st, 1839, erysipelas being excepted: 
 
 
 (Males.) 
 
 Secondary Affections. 
 
 
 
 
 
 
 03 tn 
 
 
 S . 
 
 CS GO 
 
 
 
 
 
 
 Typhus . . 
 
 to 
 
 
 >> 
 
 X 
 
 <a 
 
 "a, 
 o 
 a. 
 
 < 
 
 .2 © 
 
 MP. 
 
 "u, "£ 
 
 <D — 
 
 H 
 
 a 
 c C 
 
 to > 
 
 .2J> 
 
 « "3 
 «- > 
 
 o *-> 
 
 C to 
 
 S c 
 .2 » 
 
 .S s 
 
 "3 
 O 
 
 • •• 
 
 i 
 
 ... 
 
 2 
 
 ... 
 
 ... 
 
 1 
 
 ... 
 
 4 
 
 Febricula . . 
 
 2 
 
 ... 
 
 ... 
 
 ... 
 
 ... 
 
 ... 
 
 ... 
 
 1 
 
 3 
 
 Intestinal Fever 
 
 1 
 
 ... 
 
 ... 
 
 ... 
 
 ••• 
 
 2 
 
 ... 
 
 
 3 
 
 Pneumonia . 
 
 
 
 1 
 
 
 1 
 
 
 
 • •• 
 
 2 
 12 
 
 
 (Females.) 
 
 Secondary Affections. 
 
 
 
 Typhus . . 
 Febricula . . 
 
 09 
 
 "So 
 s 
 
 fa 
 
 a 
 
 Pneumonia &, 
 Int. Ulcers. 
 
 Synovitis. 
 
 .5 fa 
 
 m > 
 
 3 <5 
 
 o 
 
 « 
 
 S 
 w 
 
 "o 
 
 0) 
 CO 
 
 O 
 
 .2 
 
 "S 
 
 o 
 g 
 
 3 
 O 
 
 c 
 Ph 
 
 "3 
 
 o 
 
 1 
 
 1 
 
 2 
 
 ... 
 
 1 
 
 ... 
 
 ... 
 
 5 
 
 Intestinal Fever 
 
 ... 
 
 ... 
 
 ... 
 
 1 
 
 ... 
 
 • • • 
 
 ... 
 
 1 
 
 Pneumonia . 
 
 
 
 
 
 
 
 
 
 Roseola . . 
 
 ... 
 
 .. • 
 
 ... 
 
 
 
 1 
 
 
 1 
 
 Bronchitis 
 
 ... 
 
 ... 
 
 ... 
 
 ... 
 
 ... 
 
 
 1 
 
 1 
 
 8 
 
 
 
 r 
 
 folal o 
 
 ? Males and Females : 
 
 = 20. 
 
 
32 DAVIDSON ON THE CAUSES OF FEVER. 
 
 It appears from these tables that among the cases of typhus there 
 was not a single relapse into the same febrile state, characterised by 
 a new eruption and the other distinctive marks of this disease ; but 
 on the contrary that all the secondary affections were well marked 
 local diseases. It is also shown that two cases of febricula and one 
 of intestinal fever were affected with typhus during their residence 
 in the hospital ; and it is probable that more of such cases would 
 have been infected had not the precaution been adopted of dismiss- 
 ing them as early as possible. 
 
 In concluding our remarks upon relapses, we shall make the fol- 
 lowing quotation from Drs. Barker and Cheyne's work, in order to 
 show that one of the most powerful facts in favour of the doctrine 
 of relapses may be explained by the theory we have adopted. 
 These authors state that " as the epidemic advanced and particu- 
 larly in its latter stages, relapses became very common, insomuch 
 that a very large proportion of those who had been attacked suffered 
 a relapse, and with many this happened several times. ... It 
 was remarked at Roscrea that the more early the crises occurred 
 the greater was the probability of relapse. This observation will 
 apply to every part of this province, for as the epidemic fever 
 approached to a close, a fever of short duration, continuing for 
 about five days, extremely mild ancF rarely proving mortal, became 
 very frequent, and at this time the tendency to relapse was most 
 observable. On the contrary, after fever of long continuance, it 
 rarely happened that relapse took place." 1 .... The same 
 authors in their medical account of fever in Connaught, state that 
 " relapses were so rare at the commencement of the epidemic that 
 Dr. Veitch, Physician to the County Infirmary in Galway, in his 
 letter of the 6th September, 1817, says that he had not observed 
 one case of relapse out of some hundred cases of fever." In de- 
 scribing the disease as it occurred among the upper ranks in Gal- 
 way, they state that " petechia? were universal, insomuch that 
 scarcely a case occurred without them." 2 
 
 The inferences which may be deduced from these quotations are, 
 1st. That these short or five-day fevers were either not typhus or 
 their convalescence was only a remission of the disease; for we are 
 not aware of any writer on this subject who describes it as ter- 
 minating so early. 2d. Very few of those which were protracted, 
 or which continued to the end of the second or third week, relapsed, 
 which is about the average period for the duration of typhus. 3d. 
 That in Galway, where petechias or the typhoid eruption were 
 almost universal, showing the disease to be typhus, not a single 
 case of relapse occurred out of some hundred cases. 
 
 1 Barker and Cheyne on Fever, vol. i. p. 438. a Ibid. p. 455. 
 
DAVIDSON ON THE CAUSES OF FEVER. 33 
 
 Sect. III. — Sources of Continued Fevers, not Typhoid. 
 
 Pneumonia, pleuritis, peritonis, bronchitis, and modifications of 
 these affections are not unfrequently confounded with continued 
 fever, being admitted to fever hospitals as such; and thus the 
 numerical amount of non-eruptive cases of typhus is often con- 
 siderably increased by the inclusion of these diseases in the list; 
 independent altogether of the two other affections which we are 
 about to describe, and which are generally considered continued 
 fevers, although different from typhus in their prominent features 
 and laws. The first and most prevalent of these two affections has 
 been called febricula, on account of its mildness and short duration, 
 when compared with typhus. The second is prominently accom- 
 panied with derangement of the digestive organs, either in the form 
 of constipation or diarrhoea. Chomel makes the following observa- 
 tions, when treating of the diagnosis of typhoid fever: " In effect, 
 various diseases may present, during the first three or four days, a 
 great resemblance to the typhoid affection. Among the diverse 
 morbid states which may at this period present analogous pheno- 
 mena, we shall find the early symptoms of many eruptive diseases, 
 as smallpox, scarlet fever, and measles; also some catarrhal affec- 
 tions of little intensity : protracted ephemeral fever may be taken 
 for the typhoid inflammatory fever, bilious derangement for bilious 
 fever, exhaustion for the commencement of an adynamic fever, 
 and especially a latent phlegmasia either visceral or venous. . . 
 One of the most important characters of the typhoid affection is the 
 duration of the febrile state. As often as the febrile phenomena 
 which can be attached to any appreciable lesion are prolonged 
 beyond a certain limit, eight or ten days for example, there will be 
 already serious grounds for presuming an alteration of the glands 
 of Peyer ; and when a disease terminates at the end of some days, 
 we can always be assured, whatever doubts may have existed as to 
 its nature, that it was different from the typhoid affection; and 
 thus all the morbid states, the duration of which does not extend 
 to the tenth or twelfth day, are distinguished." 1 
 
 1. Sources of Febricula. This affection generally commences, 
 like typhus and several other febrile affections, with a rigor, at- 
 tended by headach, frequency of pulse^ heat of skin, flushed face, 
 thirst, moist tongue, generally more or less coated with a whitish 
 fur, and red at point and edges, more or less constipation of bowels, 
 and in the great majority of cases nncombined with any deter- 
 minate local affection. It is difficult to distinguish this fever from 
 typhus for the first four or five days; but after that the diagnosis 
 may in most cases be made with tolerable accuracy. 
 
 If the typhoid eruption be present, there can be no doubt what- 
 ever of the nature of the disease ; for in Britain this peculiar 
 
 1 Chomel, Leijons de Cliaique Medicale, torn. i. p. 400. 
 3 — f 3 dav 
 
34 DAVIDSON ON THE CAUSES OF FEVER. 
 
 efflorescence occurs in no other febrile affection that could be con- 
 founded with typhus ; but in a certain proportion of cases it is not 
 present in the latter disease. In cases of typhus destitute of the 
 eruption, there are frequently, however, other symptoms present, 
 even by the sixth day, which are rarely if at all observed in febri- 
 cula ; such as suffused eyes, delirium, or partial stupor, a dry and 
 brown tongue, a dark or dusky hue of the skin. The frequency of 
 the pulse is also a very important symptom in the diagnosis ; for in 
 febricula it is rarely above 100, and it generally continues full or of 
 moderate strength throughout the whole course of the disease; 
 whereas in many cases of typhus, the pulse becomes weak, soft, 
 small, or very compressible, at an early period of the disease, and 
 in most cases is more or less above 100 about the sixth or seventh 
 day. Sometimes this fever terminates in one or-two days, being 
 described by some authors under the name of ephemera; but more 
 generally symptoms of amendment appear about the sixth or 
 seventh day, and complete convalescence is established, in the 
 large majority of cases, from the sixth to the tenth day. Deafness 
 and desquamation of the cuticle, both of which are frequent cha- 
 racteristics of typhus, are generally absent in this affection. Again, 
 complete convalescence from typhus rarely occurs in adults before 
 the fifteenth day, and is in a majority of cases much- later. In 
 children, however, the crisis of typhus generally appears earlier 
 than in adults; but the febriculous affections to which they are 
 liable are proportionally short, often only one or two days in dura- 
 tion. The statistical facts connected with the minimum and 
 maximum duration of typhus have not been very conclusively 
 determined; for, as we formerly remarked, one class of authors 
 terminate the disease when the stage of convalescence begins, 
 while another class do not consider it terminated until the patient 
 is discharged from the hospital; and this discrepancy is still further 
 increased by not carefully classifying the different febrile affections 
 that are admitted into fever institutions and their corresponding 
 duration. 
 
 M. Chomel, who seems to have been exceedingly careful in 
 drawing his conclusions only from decided cases of typhoid fever, 
 gives the following statistical account of the duration of the disease, 
 from its commencement to the beginning of convalescence : 
 
 In 1 patient on the 8th day after attack. 
 
 1 « « 9th " 
 
 4 " " 12th " 
 
 3 " between 12th and 14th day inclusive. 
 
 10 " " 15th and 16th " 
 15 " " 17th and 20th " 
 14 " " 21st and 25th " 
 
 11 " « 26th and 30th « 
 8 " " 31st and 40th " 
 1 " on the 45th, 
 
DAVIDSON ON THE CAUSES OF FEVER. 35 
 
 "If, however/' he adds, " we throw aside the eases in which im- 
 provement has appeared before the fifteenth day, and those in which 
 it has appeared after the thirtieth, which constitute a small number 
 of exceptions, there remains fifty cases out of sixty-eight, that is 
 nearly three fourths, in which this improvement took place, from 
 the fifteenth to the thirtieth day." 1 It appears from this table that 
 there were only two out of sixty-eight cases that presented symp- 
 toms of convalescence at the eighth and ninth day, and if we add 
 five or six days for its complete establishment, the disease, even in 
 this fractional proportion of cases, could not be considered as ter- 
 minated before the thirteenth or fourteenth day. 
 
 This method of calculating the duration of fever, adopted by 
 Chomel and many other authors, is greatly inferior in accuracy to 
 that of marking the patient convalescent when he is actually free 
 of the febrile symptoms, namely, when his pulse is natural, his 
 tongue pretty clean, his sleep tolerably sound, and his appetite 
 moderately good, but still weak, and consequently unable to leave 
 the hospital for some days at least. It is quite obvious that the 
 positive character of these four symptoms renders them more fixed, 
 more easily ascertained, and not so likely to be misapprehended as 
 their relative improvement during the first stage of convalescence; 
 and therefore that it is preferable in the determination of this ques- 
 tion. 
 
 It appears necessary, before presenting our table constructed on 
 this principle, to give one which will show the whole diseases that 
 have been admitted within a certain period into the Glasgow Fever 
 Hospital, namely, from May 1st to November 1st, 1839; as some 
 of our deductions depend upon a fair and impartial consideration 
 of these cases, and as the various statistical points referred to in 
 this section were noted with care. 
 
 1 Chomel, Lecjons de Clinique Medicale, torn. i. p. 44. 
 
 3* 
 
36 
 
 DAVIDSON ON THE CAUSES OF FEVER. 
 
 
 C Typhus, 
 
 \ Febricula, .... 
 
 Males. 
 
 Females. 
 
 Total. 
 
 270 
 32 
 
 276 
 31 
 
 546 
 63 
 
 
 ' Gastric or Intestinal Fever, . 
 
 8 
 
 7 
 
 15 
 
 O 
 
 Bronchitis, .... 
 
 14 
 
 8 
 
 22 
 
 
 Pneumonia, . . 
 
 15 
 
 7 
 
 22 
 
 
 Smallpox, .... 
 Measles, 
 
 16 
 3 
 
 11 
 1 
 
 27 
 4 
 
 
 Scarlet Fever, 
 
 Hooping-cough, 
 
 Hydrocephalus, 
 
 Erysipelas, .... 
 
 Roseola, .... 
 
 1 
 1 
 
 4 
 1 
 
 3 
 2 
 
 4 
 2 
 1 
 3 
 
 2 
 
 
 Erythema, .... 
 Hepatitis, .... 
 Apoplexy, .... 
 Determination of blood to head, 
 
 1 
 ] 
 1 
 1 
 
 1 
 
 1 
 1 
 2 
 1 
 
 
 Intermittent Fever, 
 
 1 
 
 
 1 
 
 
 Cynanche Tonsillaris, . 
 
 1 
 
 1 
 
 2 
 
 
 Syphilis, .... 
 Delirium Tremens, 
 
 1 
 
 ] 
 
 1 
 
 2 
 1 
 
 
 Suppuration of Kidneys, 
 Phthisis, .... 
 
 
 1 
 
 2 
 
 1 
 2 
 
 
 Dysentery, .... 
 Mania, 
 
 
 2 
 1 
 
 2 
 
 1 
 
 368 
 
 360 
 
 728 
 
 As a considerable number of the cases in the above table were 
 not continued fevers, it may be necessary to explain one or two 
 points respecting the admissions into the Glasgow Fever Hospital. 
 The facilities of admission have of late been very great, in conse- 
 quence of there being much more accommodation than was re- 
 quired ; and every case, where there was the slightest suspicion of 
 fever, seems to have been sent to this institution, not only from the 
 city, but from its vicinity to the extent of many miles. 
 
 It may be supposed that there is a large number classified as 
 bronchitis and pneumonia ; but it requires to be stated that in all 
 the cases of the first mentioned disease, there were no typhoid 
 symptoms present, and that only two or three were arranged under 
 this division, whose convalescence extended beyond the tenth day, 
 while the greater number of the pneumonic patients were bled from 
 the arm, and the blood found decidedly buffy. 
 
 The case marked suppuration of the kidneys was one of peculiar 
 interest. The patient had been delivered of a child about a fort- 
 night before her admission, and was at this latter period found 
 quite comatose, but there were none of the peculiar symptoms of 
 typhus present. The inspection, however, cleared up any doubt 
 that existed as to the nature of the affection, for both kidneys con- 
 tained numerous small abscesses throughout their whole texture, 
 
DAVIDSON ON THE CAUSES OF FEVER. 
 
 37 
 
 there was pas in both pelves, in the ureters, and bladders, but no 
 urine in the latter organ. 
 
 We shall next present a table, showing the maximum of the 
 pulse and the period of complete convalescence in 181 cases of 
 eruptive typhus, and in thirty cases of febricula, that were admitted 
 into the Glasgow Fever Hospital from May 1st to November 1st, 
 1839, and it includes the whole that were admitted within that 
 period, except two or three, whose convalescence and pulse were 
 not noted, and those that were omitted for reasons to be presently 
 stated. 
 
 Table of the Maximum Frequency of the Pulse in 181 Cases of 
 
 Eruptive Typhus. 
 
 Males. 
 
 Females. 
 
 Maximum fre- 
 quency of pulse. 
 
 No. 
 
 of Cases. 
 
 Maximum fre- 
 quency of pulse. 
 
 No. 
 
 of Cases. 
 
 
 
 
 
 86 
 
 
 5 
 
 90 
 
 
 12 
 
 96 
 
 
 20 
 
 98 
 
 
 1 
 
 100 
 
 
 8 
 
 100 
 
 
 3 
 
 104 
 
 
 4 
 
 104 
 
 
 5 
 
 106 
 
 
 3 
 
 108 
 
 
 23 
 
 108 
 
 
 15 
 
 110 
 
 
 1 
 
 110 
 
 
 1 
 
 112 
 
 
 3 
 
 112 
 
 
 4 
 
 116 
 
 
 3 
 
 116 
 
 
 4 
 
 120 
 
 
 17 
 
 118 
 
 
 1 
 
 124 
 
 
 7 
 
 120 
 
 
 18 
 
 130 
 
 
 10 
 
 124 
 
 
 5 
 
 134 
 
 
 2 
 
 128 
 
 
 1 
 
 140 
 
 
 4 
 
 130 
 
 
 1 
 
 90 
 
 
 
 
 91=181 
 
 Average maximum 
 
 of puJse ir 
 
 i Males = 107.5. 
 
 
 a 
 
 " ] 
 
 Females = 114.1. 
 
 
 u 
 
 " I 
 
 /Tales and Females = 
 
 : 110.8. 
 
 The five cases in which the pulse is marked 86 were admitted 
 on the seventh, ninth, eleventh, fourteenth, and twenty-first days of 
 the disease, so that it is probable that partial convalescence had 
 commenced at the time the pulse was noted. 
 
38 
 
 DAVIDSON ON THE CAUSES OF FEVER. 
 
 Table showing the Day of the Disease on which complete Convalescence 
 was established in 181 cases of Eruptive Typhus. 
 
 MALES. 
 
 Females. 
 
 Day of disease. | No. of Cases. 
 
 Day of disease. 
 
 No. 
 
 of Cases. 
 
 12th 
 
 1 
 
 13th 
 
 
 2 
 
 13 
 
 4 
 
 14 
 
 
 7 
 
 14 
 
 2 
 
 15 
 
 
 11 
 
 15 
 
 9 
 
 16 
 
 
 3 
 
 16 
 
 9 
 
 17 
 
 
 9 
 
 17 
 
 9 
 
 18 
 
 
 10 
 
 18 
 
 6 
 
 19 
 
 
 6 
 
 19 
 
 7 
 
 20 
 
 
 10 
 
 20 
 
 3 
 
 21 
 
 
 3 
 
 21 
 
 10 
 
 22 
 
 
 5 
 
 22 
 
 8 
 
 23 
 
 
 2 
 
 23 
 
 2 
 
 24 
 
 
 3 
 
 24 
 
 6 
 
 25 
 
 
 1 
 
 25 
 
 2 
 
 27 
 
 
 4 
 
 26 
 
 4 
 
 28 
 
 
 1 
 
 27 
 
 4 
 
 29 
 
 
 3 
 
 28 
 
 1 
 
 30 
 
 
 2 
 
 29 
 
 3 
 
 32 
 34 
 36 
 44 
 
 
 1 
 4 
 1 
 1 
 
 
 90 
 
 54 
 
 
 2 
 
 91=181 tot. 
 
 Average convalescence in Males = 19.7 davs. 1 
 
 
 " " Females = 21.3 days. 
 
 
 " " days in Males and Females = 20.5. 
 
 Every case below twenty years of age has been excluded, be- 
 cause the maximum of the pulse varies more from childhood to 
 adolescence than during any other similar period of life ; and those 
 who died have also been excluded, as the comparison between the 
 pulse and the recovery would not be uniform in the two diseases, 
 and as the average maximum of the pulse of those cases which ter- 
 minated fatally was greater than that of those who recovered. 
 
 We have taken the eruptive cases of typhus only by which to 
 illustrate the law of convalescence and frequency of the pulse ; in 
 order to prevent any doubt as to the nature of the fever from which 
 the conclusion is drawn, and because they constitute the large ma- 
 jority of fever patients. But it may be said that though the non- 
 
 1 Dr. Henderson states that he has seen instances of convalescence on the 
 seventh and eighth days, in which the eruption had existed ; but it is not 
 mentioned at what stage of convalescence the calculation was made, and 
 what were the ages of the patients. Edinburgh Med. and Surg. Journal, 
 Oct. 1839, p. 4307 
 
DAVIDSON ON THE CAUSES OF FEVER. 
 
 39 
 
 eruptive cases constitute a small or perhaps only an exceptional 
 proportion of the whole number, they may not follow the same law 
 as the majority, but may be milder, and that the severity of the 
 cases is in proportion to the amount of eruption. Dr. Henderson 
 supports this opinion, which is founded on the examination of about 
 200 cases in the Edinburgh Infirmary. We can so far support the 
 author of this paper in regard to the general severity of the cases 
 attended with a copious eruption; but certainly there is no uniform 
 proportion between the two, for we have frequently met with mild 
 cases of typhus in which there existed a copious eruption, and oc- 
 casionally with some which terminated fatally when there were 
 only a small number of spots. Indeed, reasoning by analogy from 
 scarlet fever, to which typhus has most resemblance in the irregu- 
 larity of its eruption, we should be led to infer that the intensity of 
 the symptoms would not probably correspond uniformly with the 
 copiousness of the eruption ; for cases of scarlet fever have often 
 been found very malignant during some epidemics, although not 
 characterised by any exanthematous eruption, or by one which was 
 only extremely indistinct or evanescent. 
 
 There seems to be, therefore, no valid reason why the law of 
 typhus respecting complete convalescence and the frequency of the 
 pulse should not be deduced from the eruptive cases, as they con- 
 stitute, at least, about three fourths of the whole number, and as 
 there is no uniform proportion between the amount of the eruption 
 and the severity of the symptoms. 
 
 Table of the Maximum Frequency of the Pulse in 30 cases of Febricula. 
 
 Males. 
 
 Females. 
 
 Maximum fre- 
 quency of pulse. 
 
 No. of Cases. 
 
 Maximum fre- 
 quency of pulse. 
 72 
 
 No. of Cases. 
 
 68 
 
 2 
 
 1 
 
 72 
 
 7 
 
 74 
 
 1 
 
 76 
 
 1 
 
 76 
 
 i 
 
 82 
 
 1 
 
 84 
 
 3 
 
 84 
 
 1 
 
 88 
 
 1 
 
 86 
 
 1 
 
 90 
 
 2 
 
 92 
 
 1 
 
 92 
 
 2 
 
 
 
 96 
 
 1 
 
 
 
 100 
 
 3 
 
 
 
 104 
 
 1 
 
 
 14 
 
 
 16=30 tot. 
 
 Average maximum of pulse - 
 
 = 82.8 in Males 
 
 and Females. 
 
40 
 
 DAVIDSON ON THE CAUSES OF FEVER. 
 
 Table, showing the Day of Disease on which complete convalescence was 
 established in 30 Cases of Febricula. 
 
 Males. 
 
 Females. 
 
 Day of disease. 
 
 No. of Cases. 
 
 Day of disease. 
 
 No. of Cases. 
 
 4th 
 
 1 
 
 3d 
 
 1 
 
 7 
 
 3 
 
 4 
 
 1 
 
 8 
 
 3 
 
 5 
 
 1 
 
 9 
 
 2 
 
 6 
 
 1 
 
 10 
 
 5 
 
 7 
 
 2 
 
 
 
 8 
 
 3 
 
 
 
 9 
 
 3 
 
 
 
 10 
 
 4 
 
 
 14 
 
 
 16=30 tot. 
 
 Average convalescence = 
 
 : 8 days in Males and Females. 
 
 These tables show that, in 181 cases of eruptive typhus occurring 
 in adults, the maximum frequency of the pulse was not below 96, 
 except in five cases; that in about three fourths it was 108 and 
 upwards, and that the average maximum of the whole was 110.8. 
 They also show that only one case of typhus was convalescent on 
 the twelfth, and six on the thirteenth day of the disease out of this 
 number ; and that the average convalescence of the whole was 20.5 
 days. Contrast this with febricula, in which out of thirty cases 
 the pulse did not exceed 100, except in one patient, in whom it was 
 104; and the average maximum of the pulse for the whole was 
 only 82.8. The convalescence in any of these cases of febricula 
 did not exceed the tenth day, and their average convalescence was 
 eight days. Are there, then, reasons for maintaining the opinion 
 that these short and mild fevers are specifically different from 
 typhus, in opposition to that of Bateman and many eminent au- 
 thors? We think there are ; for if diseases are to be discriminated 
 by a difference of laws and phenomena, there is certainly in these 
 two affections a wide distinction in their symptoms, and also a dis- 
 tinct line of separation between them as regards the period of their 
 duration and the frequency of the pulse. 
 
 This view is supported by the fact that febriculous patients have 
 been frequently affected with typhus during their convalescence in 
 the Glasgow Fever Hospital, which cannot be satisfactorily ex- 
 plained on any other principle than that these two affections are 
 different in their nature. The causes which are generally assigned 
 for febricula also tend to support its disjunction from typhus; for 
 although they have not been sufficiently investigated, yet there is 
 an approximation to something like a proof, that exposure to cold 
 is more frequently an antecedent to this affection than it is to 
 typhus. The following table shows the causes that were assigned 
 
 for the following cases of febricula : 
 
 Cold. 
 
 22 
 
 Uncertain. 
 
 28 
 
 Contagion. 
 10 
 
 Total. 
 60 
 
DAVIDSON ON THE CAUSES OP FEVER. 41 
 
 This result tends to support the popular belief and that of many- 
 medical practitioners, that there is a short fever which has some- 
 times been called "a cold fever," although not necessarily attended 
 by a cough or other pectoral complaint. 
 
 It is not probable that this affection is contagious, for though 
 more than one in a family sometimes become affected, this is not 
 generally the case, as in typhus among the lower classes ; and it is 
 rare that more than one person from the same house has been ad- 
 mitted for this disease into the Fever Hospital. Besides, the fact 
 formerly stated respecting the almost uniformly typhoid and exan- 
 thematous character of the disease in the Glasgow Fever Hospital, 
 when nurses and hospital attendants became affected, has a ten- 
 dency to support this belief; for cases of febricula are always found 
 associated with typhus in every institution of this kind, when there 
 is no particular restriction respecting admission ; and if it were 
 contagious, it is probable that some of the attendants would have 
 been affected with it. And though these short and mild fevers are 
 not generally described and classified separately as to their pheno- 
 mena and laws, there is abundant evidence existing in the writings 
 of our British and Irish authors to prove that they constitute a 
 greater or less proportion of the fever cases of Great Britain and 
 Ireland. It does not appear to be confined, like typhus when not 
 epidemic, to particular localities, such as large towns, &c, and in 
 all probability it is the most common sporadic fever met with in 
 many country districts. It seems also to be capable of attacking 
 the same individual more than once during his life ; and we have 
 in a number of instances attended the same individual within a 
 few years under two different attacks, both having the same cha- 
 racteristics of mildness and shortness. If this view be adopted, it 
 may account to a certain extent for the statements that typhus fever 
 has often been known to affect a person more than once during his 
 life ; the one fever being confounded with the other. 
 
 We have no facts sufficiently conclusive to bring forward re- 
 specting its mortality ; but undoubtedly it is very small, unless 
 complicated with a particular local affection : and when a disease 
 which originally has all the characters of febricula becomes pro- 
 tracted, the diagnosis becomes so obscure that any deductions drawn 
 from it are very questionable. 
 
 If the analysis of the cases admitted into the Glasgow Fever 
 Hospital during the six months already specified be granted, it will 
 tend to reduce the number of those without eruption very consider- 
 ably. It is stated at page 26 that there were 250 cases without 
 eruption, and 441 in whom this exantheme was observed. Now 
 among these 250 cases there were 145 other affections than typhus, 
 which, being deducted from 250, leave as those really non-eruptive 
 105, being above 80 per cent, of eruptive cases. But the number 
 of those cases without eruption might be still farther reduced ; for 
 a portion of them were admitted after the tenth day of the disease, 
 when it is presumable that the exantheme might have disappeared, 
 
42 DAVIDSON ON THE CAUSES OF FEVER. 
 
 and some of them were verging on convalescence ; so that even 
 during the non-epidemic prevalence of typhus, when other febrile 
 affections bear to it a larger proportion than when it is extensively 
 diffused, the number without eruption is not very great ; and this 
 fact may account for the opinion which is held by some authors 
 and by many medical practitioners that the exanfheme is chiefly 
 characteristic of typhus during the prevalence of an epidemic. 
 
 2. Sources of Gastric or Intestinal Fever. — This febrile affec- 
 tion is very often of an ephemeral kind, lasting only two or three 
 days, and hence it is not frequently met with in hospital practice. 
 Sometimes it results from excesses in eating and drinking, which 
 have been repeated in rapid succession ; occasionally it is caused 
 by a single indulgence in some aliment difficult of digestion. Per- 
 sons who have feeble or dyspeptic digestive organs, particularly if 
 the bowels be constipated, are very liable to this affection if their 
 habits be irregular. The person attacked generally feels a kind of 
 malaise for some days previous to the rigour which often ushers in 
 the febrile symptoms ; the pulse is sometimes extremely rapid, the 
 skin hot, the tongue is coated with a thick white fur, and there is 
 frequently nausea and an uneasy feeling in the abdomen, which is 
 more or less tumid. The bowels are always either constipated or 
 there is diarrhoea, and when the latter symptom is present, even 
 when the stools are feculent, there is very generally reason to sus- 
 pect, at least at the commencement of the disease, the existence of 
 solid excrementitious matter in the cells of the colon. This affec- 
 tion is sometimes suddenly terminated by a copious perspiration ; 
 but more generally, not until the bowels have been freely unloaded 
 of their feculent contents ; and we have repeatedly met with cases 
 of obstinate constipation, in which the febrile symptoms did not 
 completely subside for six or eight days. 
 
 In many cases it may be distinguished from typhus at the com- 
 mencement by ascertaining the antecedent circumstances of the 
 patient, and by the state of his bowels and abdomen. When the 
 diagnosis is doubtful during the progress of the affection, its short 
 duration in the great majority of cases must necessarily distinguish 
 it from typhus. In some instances, however, particularly when 
 diarrhoea is present, the attack is prolonged for a week or two, and 
 sometimes for two or three weeks. In some of these cases there is 
 a tendency to peritonitis, while in others there is reason to suspect 
 some enlargement or ulceration of the glands of the intestines. We 
 are quite aware that such cases, which are not of frequent occur- 
 rence, might be called typhus fever without eruption; and in the 
 present state of our diagnostic means this question cannot be solved 
 in a satisfactory manner ; but we hope that future investigators 
 will be able to define a line by which they may be distinguished. 
 That intestinal fevers, even those of a protracted nature, are spe- 
 cifically different from typhus may be deduced from the fact that 
 repeated instances have occurred of such patients being affected 
 with eruptive typhus during their convalescence in the fever hos- 
 
DAVIDSON ON THE CAUSES OF FEVER. 43 
 
 pital, and a case of this kind is mentioned in the table of secondary- 
 diseases at page 31. Dr. Lombard, of Geneva, in a recent pub- 
 lication, maintains the opinion that there is a bilious fever which is 
 quite distinct from the typhoid fever ; but at the same time ac- 
 knowledges the extreme difficulty of the diagnosis. He states that 
 •'the facts collected justify the inference that there are insensible 
 degrees between a simple 'embarras gastrique' and the most severe 
 typhoid fever ; but it does not thence follow that there are no true 
 bilious diseases and no true gastric derangements, because we have 
 cited cases of this kind which have terminated by death without 
 presenting any of the lesions characteristic of typhoid fever ; only 
 it appears very difficult to distinguish if a mild case of gastric de- 
 rangement arises from a simple derangement of the alimentary 
 canal, or if, as in a case related of a suicide, it is accompanied by a 
 developement of the glands of Peyer. Perhaps in the lenticular 
 eruption may be found the distinctive sign of the intestinal eruption 
 and of the bilious disease. But farther observations are necessary 
 to determine this in at all a satisfactory manner." 1 
 
 Various other forms of fever than those we have described have 
 been mentioned by authors ; but we have seen no reason to be- 
 lieve, either from the account given of them or from our own ex- 
 perience, that there are any other species. 
 
 The typhoid eruption has been found in almost the whole of 
 those that were formerly considered distinct fevers ; and has iden- 
 tified into the same species, synochus, typhus mitior and gravior, 
 adynamic, ataxic, putrid, spotted, and jail fevers ; while synocha or 
 inflammatory fever is admitted to have scarcely an existence in this 
 country, and it is not very easy to conceive how inflammation 
 could exist without the presence of some local inflammatory action. 
 
 3. Bronchitis. — Bronchitis is a frequent complication of typhus 
 fever; but this inflammatory affection is also confounded with it 
 and other continued fevers when there is the strongest evidence for 
 believing that the febrile symptoms are solely dependent upon the 
 bronchial inflammation. It may be distinguished from typhus by 
 the affection of the bronchi being almost uniformly the first symp- 
 toms of the disease, as indicated by hoarseness, cough, dyspnoea ; 
 whereas the bronchitic symptoms in fever are rarely present to any 
 extent at the very commencement. The febrile symptoms in bron- 
 chitis are almost always proportionate to the greater or less severity 
 of the bronchitic inflammation, increase as it increases, and decline 
 when it is diminishing, which latter result is often well indicated 
 by the expectoration of yellowish opaque mucus. The duration of 
 bronchitis is also generally shorter than that of typhus, unless it be 
 complicated with some pneumonic inflammation ; and when this 
 occurs there may be some difficulty in determining the case. If, 
 however, there be the distinct stethoscopic signs of pneumonia, if 
 the blood be decidedly buffy, and not simply coated with a whitish 
 
 1 Clinical Remarks on Bilious and Typhoid Fevers, p. 16, 
 
44 DAVIDSON ON THE CAUSES OF FEVER. 
 
 or greenish-white pellicle, if the skin be of its natural whiteness, if 
 the febrile symptoms be proportionate to the local affection, if there 
 be no stupor, delirium, or suffusion of the eyes; even although the 
 typhoid eruption be not present, there will be a tolerable certainty 
 that the disease is not typhus fever. The effects of a full bleeding 
 are not to be overlooked ; for in pure pneumonia, its influence in 
 reducing the frequency of the pulse and the urgency of the other 
 symptoms is generally very decided, which is by no means the 
 result when typhus is associated with this disease. 
 
 I. Alleged sources of continued fevers from putrid effluvia. It 
 is a well-established fact that the accidental inoculation of the body 
 with decayed or putrid animal matter has produced morbid symp- 
 toms, resembling in some respects those of typhus fever, and many 
 medical men have been so affected, after making necroscopic in- 
 spections. There is always, however, in such cases extensive 
 local disease of the member inoculated, or a diffused cellular 
 inflammation. According to the researches and experiments of 
 MM. Gaspard, Magendie and Leuret, and Hamont, putrid animal 
 matter, when injected into the veins of healthy animals, proves 
 speedily fatal, 1 and putrid vegetable matter acts similarly, though 
 to a less degree ; while the symptoms induced have some resem- 
 blance to those in typhus fever. 
 
 The following were the symptoms which were produced in a 
 dog, into the jugular vein of which M. Gaspard injected a putrid 
 solution of fermented cabbage, on the 14th July, 1821. Some hours 
 after the injection of the liquid, there was great malaise, difficult 
 respiration, vomiting, and great weakness. At the end of nine 
 hours a very copious black and liquid stool. On the 15th, the 
 weakness was more considerable; there was lateral decubitus, small 
 and feeble pulse, ardent thirst, natural and abundant urine, free 
 respiration, strong pulsations of the heart, as in aneurism with 
 hypertrophy of that organ. On the 16th, some improvement, less 
 weakness, no pulsations of the heart, great thirst, disinclination to 
 food, fever, and occasionally vomiting of drinks; 17th, the same 
 symptoms ; 18th, symptoms aggravated, extreme feebleness, stag- 
 gering locomotion, excessive thirst, red inflamed eyes and filled 
 with mucus, tumefied nostrils obstructed with mucus, mucous 
 membrane of mouth red and phlogosed, a liquid grayish- white 
 stool with some clots of putrid blood, and death at the end of the 
 fifth day of the experiment. On dissection, the lungs were found 
 black and slightly inflamed, but still sufficiently crepitant. The 
 right ventricle of the heart contained an albumino-fibrous concre- 
 tion, which extended into the superior cava and pulmonary artery. 
 The mucous membrane of the intestines, especially that of the 
 duodenum and rectum, and a portion of the small intestines was 
 violet-red, as if ecchymosed, inflamed chiefly in the form of longi- 
 tudinal wrinkles and by irregular plates, which variegated the 
 
 1 Christison on Poisons, p: 583. 
 
DAVIDSON ON THE CAUSES OF FEVER. 45 
 
 exterior of the intestines before their incision. The mucous glands 
 of the rectum were swollen and very distinct. The mesenteric 
 glands appeared to be engorged with blood and were completely 
 inflamed, the gall-bladder was filled with black, thick, and ropy 
 bile. 1 
 
 In several particulars the symptoms of a malignant case of 
 typhus were exemplified in this experiment upon the dog; the 
 small quick pulse, the peculiar decubitus indicating great weak- 
 ness, the black stools, the red colour of the mucous membrane of 
 the mouth and fauces, the injected eyes, and finally the staggering 
 as indicative of delirium. The necroscopic inspection also furnishes 
 some points of resemblance, namely, the inflammatory patches in 
 the mucous membrane of the intestines, the enlarged glands in the 
 rectum, the swollen and engorged mesenteric glands, the black 
 ropy bile; all of which are pathological appearances more or less 
 frequently met with in typhus. M. Magendie found that fatal effects 
 were produced by confining dogs over vessels in which animal 
 matters were undergoing the process of putrefaction ; but pigeons, 
 rabbits, and Indian hogs were not in the least injured by a resi- 
 dence in the same cage for nearly a month. He repeated many 
 times this experiment with dogs, and always obtained the same 
 result with one exception ; but he states that in this case the dog 
 was acclimated, for the injection of a putrid liquid into his veins 
 had little effect upon him. The symptoms, however, are different 
 from those produced by the injection of a putrid fluid into the 
 veins; for the animals seem to die only from extenuation at the end 
 of about ten days ; and the post-mortem appearances are a total 
 absence of fat, of aliments in the stomach, and of chyle in the lac- 
 teals; while the mucous membrane of the intestines is inflamed, 
 but less so than when putrid matter is injected into the veins. 2 It 
 appears, however, well authenticated that workmen employed in 
 peculiar manufactories, and who are constantly exposed to the 
 effluvia arising from animal substances in a state of putrefaction, 
 are not subject to any of those morbid effects which result from the 
 injection of putrid matter into the veins, or, according to M. Ma- 
 gendie, to those which result from exposure to putrid effluvia; there 
 must, therefore, be some other explanation given of the last-men- 
 tioned author's experiments, or some unknown concurring circum- 
 stances must be required to bring the poison into operation. One 
 of the most remarkable and repulsive manufactories or rather 
 nuisances of this kind is the Chantiers d'Ecarrissage de la Ville de 
 Paris. It is an inclosure of many acres of ground, situated close to 
 the walls of Paris, and has existed for several centuries. Into this 
 receptacle are carried the contents of the necessaries of the city; 
 and the carcasses of 40,000 or 50,000 horses, dogs and cats are 
 flayed and cut up there annually. Various parts of these animals 
 are separated and manufactured for sale: the intestines into gut for 
 
 1 Journal de Physiologie, torn. ii. p. 16. 2 Ibid., loni. iii. p. 85, 
 
46 DAVIDSON ON THE CAUSES OF FEVER. 
 
 machinery; the fat is melted for blow-pipe lamps; the flesh, blood, 
 <fcc. are collected for manure ; a compost is made to breed maggots 
 for feeding poultry, and the bones are chiefly used as fuel. Hordes 
 of rats live in this bed of filth and extend their ravages extensively 
 in the neighbourhood. The fetor which arises from it is overpower- 
 ing, and often spreads to a great distance. It is remarkable, how- 
 ever, and contrary to every preconceived notion that could be 
 formed respecting its salubrity, that the workmen of this establish- 
 ment and their families are healthy, the most of them being stout 
 and long-lived. This fact has been established satisfactorily by 
 Parent-Duchatelet. This author states that they have all the cha- 
 racteristics of the most blooming health, that in this respect they 
 resemble butchers, and that they seem to attain longevity more fre- 
 quently than other artisans. Even new workmen employed upon 
 extra occasions, although not acclimated, do not appear to be more 
 susceptible, nor do they become affected with any disease. During 
 the time that cholera prevailed in France, not an ecarrisseur was 
 affected with the disease, and not one was sick ; and the mortality 
 of the village which is in the vicinity of Montfaucon was very 
 small when compared with that of Paris. He also quotes the 
 innocuous influence of the human bodies which are exhumed to 
 the extent of 200 annually from Pere la Chaise, and the exhuma- 
 tions from the Cemetery des Innocents, amounting to about 20,000 
 bodies annually, which occupied three years in the execution, and 
 which was also carried on during the greatest heats of summer. 1 
 Dissecting rooms are also situations where putrid effluvia are con- 
 stantly present; and it has been affirmed that those who are much 
 confined to these places do not enjoy good health, and are subject 
 to fevers. MM. D'Arcet and Parent-Duchatelet state that the most 
 frequent indisposition among those who are engaged in dissections 
 is dyspepsia and diarrhoea, but that this latter affection is frequent 
 among the strangers who arrive at Paris. These authors cite an 
 immense number of authorities of the highest respectability, namely, 
 Boyer, Dupuytren, Lallemand, Roux, Jadelot, Breschet, &c. to 
 prove that dissecting rooms are not insalubrious and are not pro- 
 ductive of fevers. M. Andral states that gastro-enterite, meningitis, 
 and typhoid fever are common among the young eleves of medi- 
 cine during the first year of their residence at Paris; but so little 
 does this depend upon their sojourn in the dissecting amphitheatre, 
 that among those who are affected, there is at least as many seized 
 before they commence their dissections as after this period. He 
 adds that the health of the men employed in handling the debris of 
 dead bodies is similar to that of other individuals. 3 The workmen 
 employed in the manufacture of strings for musical instruments are 
 exposed constantly to the putrid effluvia of animal substances, 
 arising from their long maceration, and they are not more subject 
 to fevers than other tradesmen. 
 
 ' Annales d'Hygiene Publique, torn. viii. p. 139. a Ibid., torn. v. p. 301. 
 
DAVIDSON ON THE CAUSES OF FEVER. 47 
 
 Butchers, who are believed by some authors to be almost exempt 
 from fevers, are exposed in the slaughter-house to the emanations 
 arising from the putrid blood and other animal fluids, which are 
 frequently allowed to stagnate, and which are sufficiently indicated 
 by the fetid and insupportable odour which issues from these 
 places during hot weather. The atmosphere of whale vessels must 
 be constantly impregnated or rather saturated with the effluvium 
 that issues from large and numerous fishes; yet fevers are not 
 prevalent among the seamen. Magendie slates that the most dele- 
 terious animal poison is the putrid water of fishes: when some 
 drops of this water are injected into the veins, in less than half an 
 hour symptoms very similar to thoso existing in typhus and yellow 
 fever are produced, and the animal dies in about twenty-four 
 hours. 1 It appears from these facts that persons may live con- 
 stantly amidst the most concentrated putrid animal emanations 
 and yet not contract fever of any type ; may enjoy health of the 
 most perfect kind ; attain longevity in many instances, and be less 
 subject to some epidemic diseases than the inhabitants in their 
 neighbourhood. It may be asked how are the experiments of M. 
 Magendie and others to be explained upon this view? It does not 
 appear from M. Magendie's experiments that the same symptoms or 
 pathological appearances were produced by exposing dogs to putrid 
 animal emanations, as by injection of a putrid fluid into the veins ; 
 indeed, he admits this himself; but adheres to the belief that the 
 effluvium was the cause of death in the dogs subjected to experi- 
 ment, although no injurious effects were produced on several other 
 animals. Many animal poisons, however, operate differently on 
 different organs and tissues ; and this is well exemplified in an 
 experiment mentioned by Dr. Christison, namely, that " a pupil of 
 Professor Mangili swallowed at once the whole poison of four 
 vipers without suffering inconvenience ;" 2 but if a small a^uantity of 
 this be inserted into a wound, poisonous effects are always pro- 
 duced. From a consideration of the whole evidence that might be 
 adduced respecting this point, it may be drawn as a conclusion that 
 although putrid matters, when injected into the veins of animals, 
 cause death under symptoms similar to those of typhus fever, yet 
 that the effluvia arising from similar matters do not under ordinary 
 circumstances produce any deleterious effects on man. That there 
 are exceptions to this general law we doubt not, such as Olivier 
 being affected with diarrhoea after visiting a cellar filled with old 
 bones, and Chevallier being seized with the same disease after ex- 
 posure to the emanations from dead bodies ; but that the effluvia 
 arising from animal substances in a state of putrefaction constitute 
 any regular source of continued fevers, we think there are no 
 grounds for believing. 
 
 II. Alleged sozirces of continued fevers from the exhalations of 
 
 1 Journal de Physiologie, torn. iii. p. 83. 
 
 2 Christison on Poisons. 3d Ed, p. 577, 
 
48 DAVIDSON ON THE CAUSES OF FEVER. 
 
 the human body. Another modification of putrid miasmata has 
 been noticed by almost all authors as a cause of fever, namely, the 
 concentrated exhalations from the human body. Sir John Pringie 
 and other army as well as navy physicians have remarked that 
 fever was often produced in crowded hospitals, especially during 
 hot weather, and also in crowded barracks and in transport ships, 
 when filled beyond a due number. Dr. Tweedie makes the follow- 
 ing- statement : " The late Mr. John Pearson told me that when he 
 was surgeon of the Lock Hospital, he uniformly observed when 
 more than a certain number of patients were placed in any of the 
 wards, fever became prevalent in the establishment ; and that from 
 repeated observation of this fact, he was induced to restrict the 
 number of beds in each ward, and never afterwards witnessed the 
 recurrence of fever in the house." 1 Dr. Bateman remarks that " if 
 it had not been already demonstrated, on the most copious evidence, 
 that the mere accumulation of animal matter in a putrescent state 
 is incapable of generating fever ; yet the fact that the closeness of 
 the habitations of the poor, the uncleanliness of their persons, furni- 
 ture, and apparel, and the accumulating filth in the lanes and 
 alleys which they occupy remain unchanged in all seasons, while 
 epidemic fever appears but rarely and with long intervals of ab- 
 sence, is decisive against the supposition that the latter is engen- 
 dered from such sources." 2 It is singular that a writer of such 
 distinguished accuracy, after having drawn so fair a conclusion 
 from the facts connected with the prevalence of fever, should appa- 
 rently contradict this ; for he states in a note that " the morbid and 
 even natural effluvia of the living body, when allowed to accumu- 
 late by want of cleanliness and air, are unquestionably common 
 sources of fever, and contribute mainly to its propagations as has 
 been intimated in the preceding note." 2 The inhabitants of some 
 countries, such as the natives of Kamstchatka, are remarkable for 
 their filth and for living amidst the most foul and putrid effluvia; 
 and yet fever is not known among them. The places they live in 
 are called yourts, which "are sunk seven or eight feet below the 
 surface of the ground, and are covered with a thatched roof in the 
 form of a truncated cone, open at the top; they consist of one small 
 apartment, which usually contains six families, with their utensils 
 and stock of provisions for the winter, the chief part of which is 
 
 dried fish almost putrefied Here they eat, drink, and 
 
 sleep, crowded promiscuously together, and satisfy all the calls of 
 nature without modesty or restraint, and never complain of the 
 noxious odour that prevails in these habitations." 3 
 
 The same mode of living is practised by the inhabitants of the 
 Island of Oonalaska, by the Samoiedes, by the Greenlanders and 
 Esquimaux ; and there are no continued fevers among them, 
 
 1 Tweedie's Clinical Illustrations of Fever, p. 83. 
 
 2 Bateman on Fever, pp. 5, 6, and 7. 
 
 3 Bancroft on Yellow Fever, &c. p. 121. 
 
DAVIDSON ON THE CAUSES OF FEVER. 49 
 
 although scurvy prevails to a considerable extent. In many parts 
 of Russia the same system of living in filthy and unventilated 
 houses, and in an atmosphere saturated with human effluvia, is 
 practised ; yet no febrile disease is the result. Dr. Bancroft quotes 
 the slave-ships as examples, where an atmosphere is more offen- 
 sively impregnated with human exhalations, excretions, &c. than 
 could probably be found in any other place of confinement, and 
 makes the following statement: "I am fully convinced that fever 
 of any kind rarely occurs on board these vessels, and contagious 
 fever never ; though great mortality has frequently happened from 
 
 other diseases, and more especially from dysentery 
 
 There certainly is nothing in the constitutions of the negroes which 
 exempts them from typhus or contagious fever; on the contrary 
 they have been found as susceptible of it as whites, and consider- 
 able numbers of them who were sent from this country and from 
 Nova Scotia to the new colony of Sierra Leone died of it on their 
 passage thither, as will be more fully related in another place." 1 
 
 Dr. Bancroft quotes a very remarkable instance of crowding in 
 the Decade frigate during the revolution in France; where 193 
 persons were crowded to as great a degree as tne negroes are in 
 slave-ships, yet not one of them died during a period of ninety-six 
 days. 
 
 IIT. Alleged sources of jail fever from filth and an impure air. 
 The breaking out of fever in jails has often been brought forward 
 as a proof of the origin of the disease from filth and impure atmo- 
 sphere, being afterwards propagated by contagion ; and Sir John 
 Pringle's aphorism is frequently quoted or alluded to by writers on 
 fever, namely, that "the cause seems plainly to arise from a cor- 
 ruption of the air pent up and deprived of its elastic parts by the 
 respiration of a multitude, or more particularly vitiated with the 
 perspirable matter, which, as it is the most volatile part of the 
 humours, is also the most putrescent." 
 
 Dr. Bancroft makes the following very pertinent remarks upon 
 this point: " That this fever often exists in them (jails) cannot be 
 denied; but this circumstance can afford no evidence of its having 
 been generated therein any more than the multiplication of vermin 
 in such places could demonstrate the spontaneous generation of 
 these and other insects by the nastiness which favours the deposi- 
 tion and hatching of their eggs. 3 .... Indeed, if it were true 
 that the vegetable or animal matters while decomposing or putrefy- 
 ing could, de novo, generate contagion properly so called, the spe- 
 cies or varieties of contagion ought necessarily to have become as 
 numerous and various as the matters so decomposing, and also as 
 various as their relative proportions; every dunghill, every collec- 
 tion of rubbish and filth, ought to be capable of generating the 
 cause of a new disease, and that disease ought to be capable of 
 reproducing itself in other persons." 3 In estimating the value of 
 
 1 Bancroft on Yellow Fever. &c. p. 129. 2 Ibid. p. 149. 3 Ibid. p. 105. 
 3 — g 4 dav 
 
50 DAVIDSON ON THE CAUSES OF FEVER. 
 
 the testimony that is generally brought forward to prove the spon- 
 taneous origin of fever in jails, and the great improbability of the 
 first person attacked, who may have been resident there for several 
 months, being infected previously to his imprisonment, the remarks 
 which we formerly made respecting the impossibility of tracing the 
 contagion in similar situations, even of diseases universally admit- 
 ted to arise from that cause alone, will also apply here. And 
 although jails may apparently be the most secure places against 
 the inroads of contagion, from the number of their bars and gates ; 
 yet their inmates, from the nature of their offences and their depen- 
 dent situation, must have a more frequent communication with 
 their friends, either personally or through the medium of clothes, 
 than is generally supposed, and that too frequently with the most 
 filthy and debased of the human race. The question relative to the 
 spontaneous origin of fever in jails seems to be almost solved by 
 the fact that the same cause existing in a variety of other situations 
 produce no disease like continued fever; and it can be proved from 
 the history of other prisons, namely, those in Switzerland, Italy, 
 Russia, &c, and similarly circumstanced as to filth, want of venti- 
 lation, <fec, that no such diseases were known there. Mr. Howard, 
 who has investigated this subject in his work on prisons, slates: 
 " If it were asked what is the cause of the jail fever, it would, in 
 general, be readily replied, the want of fresh air and cleanliness; 
 but as I have found in some prisons abroad, cells and dungeons as 
 offensive and dirty as any I have observed in this country, where, 
 however, this distemper was unknown, I am obliged to look out for 
 some additional cause for its production." 1 
 
 The following fact is worthy of being quoted, as illustrative of 
 the efficacy of cleanliness and disinfection of suspected clothes, &c. 
 in preventing the introduction of fever into jails, which were for- 
 merly so much infected by this disease: " In the jail at Cork, the 
 prisoners remained free from fever when it had spread in every 
 direction among the inhabitants of the city. To prevent its intro- 
 duction, means were employed which deserve record: jail dresses 
 were provided for the prisoners, whose clothes on their admission 
 were removed and heated in a stove, and their persons washed and 
 cleaned; the bedding was occasionally steeped in oxymuriatic acid 
 water and then stoved; patients in whom fever showed itself were 
 immediately removed to an hospital; this system was continued 
 during a year and a half, in the course of which time two prisoners 
 died of dysentery but none of fever; when the medical inspector for 
 Minister made his visit to the jail, the system had for some time 
 been discontinued in consequence of the expense attending the jail 
 dresses, and then fever began to show itself among the prisoners, 
 and a few cases were found in the jail at that time." 2 
 
 From a review of the whole facts connected with filth and 
 
 1 Bancroft on Yellow Fever, &c. p. 149. 
 1 Barker and Cheyne od Fever, vol. i, p. 97. 
 
DAVIDSON ON THE CAUSES OF FEVER. 51 
 
 deficient ventilation, it appears that both in the countries where 
 continued fevers prevail and in those where they do not exist, the 
 inhabitants may live constantly amidst this impurity and yet be 
 entirely exempt from any febrile disease of this kind; and that if 
 filth and an impure air were a common source of fever in jails, hos- 
 pitals, &c, without the influence of contagion, they would produce 
 the same effects in all other countries and localities similarly situa- 
 ted and circumstanced. The opinion, therefore, which is so gene- 
 rally admitted and propagated by many of our first authorities, that 
 fever may arise from common causes, such as putrid miasmata, 
 contaminated air, &c, and yet afterwards be propagated by conta- 
 gion, receives no support from this presumed source; for though 
 we are not prepared to assert that febrile affections may not, under 
 peculiar circumstances, arise from these causes; yet it is undoubt- 
 edly deducible from the evidence that they are not ordinary or even 
 limited though regular sources of the disease in any form. 
 
 IV. Alleged sources of continued fevers from river malaria. 
 Before concluding this part of the essay, we shall notice an hypo- 
 thesis which has lately been somewhat confidently brought for- 
 ward to account for the prevalence of typhus in some large cities, 
 namely, that a peculiar malaria is generated by the animal and 
 vegetable filth which accumulates along the sides of rivers running 
 through large towns, and that the inhabitants who live in their 
 immediate vicinity become thereby subject to fever. We are quite 
 aware that very disagreeable and sometimes fetid effluvia occa- 
 sionally arise from such situations, particularly during hot wea- 
 ther; but that it is capable of causing continued fever has not even 
 been rendered probable by any satisfactory evidence. 
 
 We presume that this point may be determined by the locality 
 of Glasgow; for the Clyde runs through the town, and has a 
 numerous population inhabiting houses close to its banks. This 
 river is also of considerable magnitude ; and certainly there is 
 abundance of filth deposited in its bed by the numerous common 
 sewers and public works in Glasgow. We have kept a record of 
 the places of habitation of 934 persons who were admitted into the 
 Glasgow Fever Hospital from January 1st to November 1st, 1839, 
 and have classified the cases in the manner shown in the following 
 table. The town has been divided into seven districts: 1, includes 
 all the streets parallel to the river and close to its banks on both 
 sides ; 2, all the streets on both sides of the river, which run at 
 right angles to it and which open into it — these first two divisions 
 are of course excluded from the others; 3, east district of the town, 
 from the cross eastward; 4, west district, from Buchanan street 
 westward, and bounded on the north by Sauchie-hall road; 5, north 
 side, northward of Sauchie-hall road and Rotten row; 6, south side 
 of the river, with the exception of those streets close to its banks or 
 which open into it; 7, centre of the town, from the Cross to 
 Buchanan street, and bounded on the north by Rotten row. 
 
 4* 
 
52 
 
 DAVIDSON ON THE CAUSES OF FEVER. 
 
 Streets close and parallel to river . 
 
 Males. 
 
 Females. 
 
 Total. 
 
 14 
 
 10 
 
 24 
 
 Streets at right angles to and opening 
 
 
 
 
 into river ..... 
 
 56 
 
 51 
 
 107 
 
 East district of town 
 
 140 
 
 136 
 
 276 
 
 West district of town 
 
 44 
 
 54 
 
 98 
 
 North side of town .... 
 
 44 
 
 41 
 
 85 
 
 South side of town .... 
 
 41 
 
 22 
 
 63 
 
 Centre of town .... 
 
 92 
 
 106 
 
 198 
 
 From the country, 2 to 14 miles 
 
 46 
 
 37 
 
 83 
 934 
 
 It is shown by this table that among 934 cases admitted as 
 labouring under continued fever, there were only twenty-four who 
 inhabited houses close to the river ; and when we lake into calcu- 
 lation the large population that live upon its banks, this proportion 
 is very small. Again, in those streets which run at right angles to 
 the river, and which open into it, the number is greater ; but it 
 must be remembered that most of these streets are long, and that it 
 is only those inhabitants who live at their river termination that are 
 at all exposed to the effluvia. If this be taken into the account, a 
 fractional proportion only of these 107 cases ought to be calculated. 
 The east district of the town, a situation very remote from the 
 river, furnished nearly one third of the whole cases, and it and the 
 centre of the town together more than the half. These facts clearly 
 show that river malaria has no influence in the production of con- 
 tinued fevers in Glasgow, and that it is proportionally as prevalent 
 if not more so, in other and more central parts of the town, 
 
 CHAPTER II. 
 
 Circumstances favouring the Diffusion of Continued Fevers. 
 
 Epidemic diseases have prevailed from the most remote era of 
 the world, and have, with one exception, hitherto bid comparative 
 defiance to the philosophy of medicine, in its attempts to check 
 their progress or diminish their mortality. Almost every country 
 has its own peculiar pestilence, that sweeps rapidly away its redun- 
 dant population at periodical seasons ; and then its fatal operation 
 ceases, partly from the subjects it can attack being reduced in num- 
 ber, and partly because its laws rendered it progressive from one 
 city or country to another, or because the element that favoured its 
 operation had been changed or modified in its constitution, Many 
 
DAVIDSON ON THE CAUSES OF FEVER. 53 
 
 diseases, the contagious as well as the non-contagious, possess the 
 property of becoming epidemic; and smallpox, which is perhaps 
 the most infectious of all febrile affections, is subject to the same 
 law, being rapidly diffusible during some particular seasons, while 
 in others it remains comparatively inactive. The same periodical 
 prevalence of scarlet fever and measles is observed during parti- 
 cular seasons, as of yellow fever, which is generally believed to be 
 a non-contagious disease, and to derive its origin from vegetable 
 malaria generated in a hot climate. 
 
 There are four prominent circumstances which favour the diffu- 
 sion of contagious continued fever : 
 
 1st. A humid state of the atmosphere. 
 
 2d. Poverty, famine, or food of bad quality. 
 
 3d. An accumulation of persons not previously affected. 
 
 4th. Filth and deficient ventilation. 
 
 We do not mean, however, to assert that these are the only cir- 
 cumstances that operate in the diffusion of contagious fever ; for 
 certainly our knowledge of the constitution of the atmosphere, par- 
 ticularly its meteorological and miasmatic qualities, warrants no 
 such conclusion. But if it can be shown that these circumstances 
 generally precede or accompany an epidemic of typhus fever ; 
 although they may not account for all the phenomena connected 
 with its extension, yet may so far elucidate the subject as to facili- 
 tate the progress of future observations or experiments. 
 
 1. Humidity of the atmosphere, scarcity of provisions, filth : 
 and deficient ventilation, tend to diffuse continued fevers. Almost 
 all authors who have written on epidemic diseases have noticed 
 what is called an epidemic constitution of the atmosphere ; but this 
 has in general been so indefinitely stated, far less defined, that no 
 conclusion can be drawn from their descriptions as to the peculiar 
 alterations of which it consists. We shall, therefore, confine our 
 evidence solely to that state of the atmosphere which is either cog- 
 nisable by our senses or by instruments, as it is impossible in the 
 present state of our knowledge to advance any thing but vague 
 hypothesis, upon what authors designate by the term referred to. 
 Typhus fever is a disease peculiar to cold or temperate regions, and 
 it does not appear that it is capable of propagation to any extent in 
 a hot climate ; the powerful heat of the sun in such regions ap- 
 pearing to dissipate or destroy its contagious properties. Dr. Ban- 
 croft observes that "in voyages to the East Indies, ships remain 
 for a much longer space of time between the tropics, and being 
 also exposed to a higher temperature, the power of heat in destroy- 
 ing typhus fever is in them more decisively manifested, an entire 
 cessation of the disease (however prevalent) commonly taking place 
 before they can reach the Cape of Good Hope. It has indeed never 
 been known, as I am informed, that a single case of this fever had 
 occurred on either side of the Indian peninsula. 551 The existence 
 
 1 Bancroft en Yellow Fever, &c. p. 510. 
 
54 ' DAVIDSON ON THE CAUSES OF FEVER. 
 
 of typhus fever, at least its diffusion, seems therefore incompatible 
 with a powerful or tropical heat of the sun, and in that respect it 
 differs very essentially from yellow fever ; but the ordinary heat of 
 a temperate climate does not extinguish it or even materially check 
 its progress ; for it has often prevailed epidemically during summer 
 as well as winter ; though it has been generally observed that the 
 seasons during its prevalence were attended with more than the 
 average quantity of rain. In adducing evidence to prove this point, 
 we shall also include that which establishes the coexistence of 
 scarcity of provisions with its consequences, namely, filth and defi- 
 cient ventilation, as the descriptions of authors generally compre- 
 hend these concomitant circumstances. Drs. Barker and Cheyne 
 state on the authority of Rogers, that "after the year 1721, there 
 was again an interval of good health in Ireland so complete, that 
 scarcely a case of fever was to be met with ; this continued till the 
 year 1728, when, as we learn from Boulter's Letters, there had 
 been three bad harvests in succession. Oatmeal, the chief food of 
 the poor in the north, rose to an extravagant price ; in the south, 
 the scarcity was so severely felt, that on the 26th of February there 
 was a great rising of the populace of Cork, who threatened to pull 
 down the Mayor's house. . . . From 1728 fever gained ground, 
 and continued to be epidemical until 1732. ... In the winter 
 of 1739-40 an intense frost attended with a high wind at S. E. and 
 E., intolerably piercing, set in on the 27th of December, and con- 
 tinued with little interruption till the middle of February." The 
 following season was one of great scarcity, and in " the autumn of 
 1740, which was unusually frosty, with a continued prevalence of 
 N. and E. winds, fever which had been frequent became epide- 
 mical ; it did not cease in the winter, and increased most alarm- 
 ingly in the spring and summer of 1741." O'Connell estimated 
 the mortality of that epidemic at 80,000 persons. " The year 1S00 
 was nearly as unfavourable to the fruits of the earth as 1799. The 
 summer of that year was unusually dry ; then followed a short 
 period of uncommon heat; for three weeks or a month the ther- 
 mometer, when at its greatest height during the day, seldom fell 
 below 70 degrees ; cold and wet weather set in about the end of 
 August or beginning of September. Thus a short period of un- 
 common heat degenerated into an ungenial autumn, yielding in 
 some soils an imperfect produce, whilst in others, the failure of the 
 crops was little less complete than in the preceding season; so that, 
 notwithstanding bounties were granted on the importation of for- 
 eign corn, and the distillation of spirits from grain prohibited, yet 
 the price of bread and potatoes, both of bad quality, together with 
 that of every other necessary of life, was raised beyond all prece- 
 dent. In the autumn and winter of 1800, the inhabitants of this 
 kingdom universally suffered from a contagions fever, in which 
 
 the troops stiil continue to participate In August, 
 
 1801, the garrison of Dublin suffered greatly from petechial fever, 
 which very generally prevailed among all ranks in the metropolis 
 
DAVIDSON ON THE CAUSES OF FEVER. 55 
 
 and its vicinity. The epidemic which had now reached its height 
 shortly after began to decline, but not before the good effects of an 
 unusually abundant harvest, in again furnishing provisions of all 
 kinds to the poor at a moderate rate, had been felt. The winter of 
 1813-14 had been uncommonly severe, that of 1815-16 did not 
 foil short in severity ; but particularly so in the early part of 1816, 
 when the cold was very great in these countries. In the month of 
 February, 1816, the quicksilver in the thermometer in many parts 
 of England fell below 0°. Thus at Northampton, on the 9th of 
 February, 1816, it fell to 4°, and on the 10th to 2.75°. In the 
 neighbourhood of London it fell to 5° below 0°, and during four 
 
 days of that month it never rose to the freezing point 
 
 From a registry of the weather kept in Dublin, it appears that the 
 mean temperature of the months of spring, summer, and autumn, 
 commencing with February and ending with October of that year, 
 was nearly three degrees and a half below that of the similar pre- 
 ceding period; thus the medium temperature in 1815 was 54.32°, 
 and during the same time in 1816 it was only 50.9°, the difference 
 amounting to 3.42°. In neighbouring countries similar observa- 
 tions were made. According to those of Mr. Howard, in the neigh- 
 bourhood of London, the mean temperature of the same months in 
 1815 was 53.9°, and in 1816 only 49.9°, the difference amounting 
 
 to fourdegrees The quantity of rain which fell during 
 
 the summer and autumn of 1816 was also very great. During the 
 months commencing with July and ending with October in that 
 year, being the season of harvest, the humidity of the atmosphere 
 was almost incessant: rain falling during the greater part of the 
 time in these months. . . . The effects occasioned by unusual 
 cold and humidity, and absence of sunshine on the productions of 
 the soil were peculiarly injurious. The harvest of grain was un- 
 commonly late both in this country and in England. Corn re- 
 mained uncut during the latter parts of October and November, 
 and much of it was altogether lost. The same injurious effects on 
 the quality of the potatoes were produced as upon the grain, and 
 these roots constitute "the principal or only food of the poor" in 
 most parts of Ireland. " The sufferings of the poor at this period 
 did not depend on diminution of vegetable food only; in many or 
 most parts of Ireland, the straw used for bedding was often half 
 decayed, and more than usually disposed to imbibe and retain 
 
 humidity; perhaps from deficiency of the woody fibres 
 
 Turf or peat is the chief fuel of the poor in this country, and during 
 such wet seasons it could not be cut and dried for use. So great 
 was the scarcity of fuel, that the hedges, which in ordinary times 
 are respected as the boundaries of property, were destroyed, and 
 the trees in many places were denuded of their branches to supply 
 the necessaries of life ; a practice at which landed proprietors often 
 connived, sensible that it had arisen from necessity the most urgent. 
 Hence dampness of clothes and bedding, imperfect cooking of food 
 and ventilation of apartments ? deficient cleanliness in persons and 
 
56 DAVIDSON ON THE CAUSES OF FEVER. 
 
 dwellings, all depending on the want of fuel, contributed to heighten 
 and extend the calamities of the poor of Ireland at this eventful 
 period. The preceding statement refers to the effects of the cold 
 and wet of 1816 chiefly, but the following year was little inferior 
 in severity. The summer and autumn were humid, cold, and un- 
 genial, and agricultural produce, with the exception of potatoes, 
 which were more abundant than in the former year, was almost as 
 scarce as in 1816. . . . The year 1818 was remarkable for a 
 state of weather the reverse of that in the years immediately pre- 
 ceding. The spring was moist, but the summer set in with unu- 
 sual warmth, and proved the hottest which has occurred in this 
 country during many years past." To these causes of distress were 
 added a very low price for labour, and extensive failures in trade 
 and manufactures. Drs. Barker and Cheyne also mention the pre- 
 valence of fever on the continent of Europe during a series of pre- 
 vious years, and remark very justly that " the circumstances ©f the 
 inhabitants of a great portion of the continent at this time, arising 
 from the distress occasioned by its being the seat of war, must have 
 strongly resembled those of the people of Ireland during 1 the late 
 scarcity of provisions. At a later period, in 1817, after a failure of 
 the crops, epidemic fever existed in the southern parts of Italy. . 
 . . . Prom the same authority (Dr. Pockles) we learned that in 
 the early part of 1817, scarcity of food was so great in Germany, 
 that many died of hunger ; but no epidemic fever existed there at 
 that time. It had prevailed in that country three years previously, 
 and did not then originate in scarcity of provisions, but was traced 
 to the miserable remnant of the French army which entered that 
 country after its overthrow in Russia. From the facts here ad- 
 duced, it follows incontrovertibly, that during the times of its in- 
 crease in Ireland, fever was very prevalent in most parts of the 
 continent, and that the circumstances which caused it to spread 
 
 epidemically were not peculiar to this island But 
 
 whatever may have been the causes which have rendered the dis- 
 ease more than usually frequent during the last nine or ten years, 
 no distinct evidence has been obtained of its introduction from the 
 continent ; and an inspection of the preceding table (vol. i. p. 49) 
 points out that the rapid increase of the disease depended on general 
 causes, operating on most parts of the country at the same time. 
 For we find that it commenced in places situated most distant from 
 each other in different parts of Munster and Ulster, at the end of 
 1816 or beginning of 1817; and making the proper allowance for 
 the difficulty of determining when fever became epidemical in 
 places which are always infested by the disease, we must admit 
 that the periods of its manifest increase were nearly coincident. In 
 fact, the scarcity of provisions combined with want of employment, t 
 whatsoever their mode of operating may have been, appears as the' 
 main cause of the spreading of fever epidemically through this 
 country; although it must also be acknowledged that the simulta- 
 neous increase of this disease in Ireland and on the continent, leads 
 
DAVIDSON ON THE CAUSES OF FEVER. 57 
 
 to the inference that whatever may have been its origin an epidemic 
 constitution prevailed over a great part of Europe during a series 
 
 of past years With respect to the time of its greatest 
 
 prevalence in each of the four provinces it is not easy to decide. 
 In Munster, it appears to have been most prevalent in the summer 
 of 1818, and in Connaught about the same time, whilst the other 
 provinces, where its commencement was latest, the time of its 
 greatest prevalence was referred in Leinster generally to the au- 
 tumn of 1817, and in Ulster to the winter of that year, In the 
 principal cities, Dublin, Cork, and Limerick, it was most prevalent 
 in the summer and autumn of 1818. m 
 
 We have thus made very copious extracts from Drs. Barker and 
 Cheyne's valuable record of the epidemic fever in Ireland ; as it 
 contains a greater amount of facts and observations respecting this 
 disease than any work that we have consulted. Indeed, when we 
 consider that about one fourth, or a million and a half, of the popu- 
 lation of Ireland were affected with fever, during the two years that 
 it prevailed, and that accurate communications were received from 
 respectable physicians residing in all the provinces, and that these 
 have been admirably concentrated and illustrated by the authors, it 
 must be considered one of the most important as well as interesting 
 descriptions of the rise, progress, and decline of this disease. 
 
 Dr. Adams states that "during the winter of scarcity in 1799 
 and 1800, fever from infectious atmosphere was so general as to 
 excite us to imitate the example of those manufacturing towns 
 which are never free from the disease, and a fever-house was esta- 
 blished in London." 2 Dr. Bateman remarks that "deficiency of 
 nutriment is the principal source of epidemic fever, and that the 
 circumstances just alluded to (improvement in all the arts of life,) 
 operate only as accessories in fostering and multiplying it will 
 
 scarcely admit of dispute The last epidemic which 
 
 occurred in London followed a scarcity of two successive years 
 (1799 and 1800): and it was during the prevalence of this fever 
 that the necessity for establishing a House of Recovery became 
 manifest. . . . Whether the epidemic of 1817 has been really 
 much more extensive than the former, I am unable to determine. 
 . . . . It might have been expected, indeed, that the present 
 epidemic would exceed the last in the extent of its course, since it 
 occurred at a period of unparalleled distress among the labouring 
 poor; when the loss of employment, occasioned by the termination 
 of the war and the general suspension of the manufactures, con- 
 curred with the failing harvest of 1816 to increase the difficulties 
 of procuring subsistence." 3 Dr. Tweedie observes that "it is an 
 undeniable fact, founded on the experience of many epidemics, that 
 there are certain circumstances which render the system peculiarly 
 
 1 Barker and Cheyne on Fever, pp. 25-107. 
 
 2 Adam's Inquiry into the Laws of Epidemics, p. 30, 
 1 Bateman on Contagious Ifevetj pp, 4 to 11. 
 
58 DAVIDSON ON THE CAUSES OF FEVER. 
 
 predisposed to the action of febrile causes ; and the connection of 
 scarcity and privation with the occurrence of fever among the 
 lower classes of the community, has been so often verified by the 
 experience of epidemics, as now to be received as a general axiom." 1 
 The same author also makes the following observations on the 
 influence of the temperature and moisture of the atmosphere: 
 " Though fever can scarcely be said to have prevailed extensively, 
 or to adopt the common phrase, to have been epidemic in London 
 since 1820, yet the diminution of autumnal fevers, for the last two 
 seasons, proves decidedly how much some unknown condition of 
 the atmosphere influences its prevalence. This condition is inti- 
 mately connected with the combined effects of heat and moisture ; 
 hence cold and wet summers are always remarked to be compara- 
 tively healthy, while disorders of the bowels in such seasons are 
 seldom observed. The number of patients admitted into the Fever 
 Hospital in the autumn months of the last three years establish this 
 principle. In August. September, and October, 1827, there were 
 admitted 205 : in the same months of 1828, the numbers were 170; 
 in the autumn of 1829, only 94 were received. The cause of this 
 progressive diminution is undoubtedly to be traced to the cold wet 
 summers of the last two seasons." 2 An opinion, exactly opposed to 
 that of Dr. Tweedie, is given by Dr. Armstrong. He states that 
 "in England typhus is evidently favoured by a low temperature, 
 being most prevalent in the cold seasons of winter and spring, 
 generally abating or disappearing as the heat of summer advances, 
 and often prevailing to a considerable degree in cold wet autumns." 3 
 Dr. Alison makes the following statement respecting the cause of 
 the epidemic fever which prevailed in Edinburgh during the years 
 1826-7: "The chief cause of the unusually great and rapid exten- 
 sion of fever during last winter was no doubt the very distressed 
 condition of a great part of the lower order of inhabitants, in conse- 
 quence of the diminished expenditure of the higher ranks, and par- 
 ticularly of the failure of many speculations in building, which had 
 given employment to great numbers of masons, joiners, plasterers, 
 
 and labourers A very great number of the patients 
 
 received into the hospitals in fever belonged to families of which 
 the working members had been out of employment for periods 
 varying from six weeks to six months; and Edinburgh has fur- 
 nished but too many opportunities, both recently and formerly, for 
 observing that it is among such distressed families that fever spreads 
 most rapidly and extensively." 4 
 
 Dr. Cowan attributes the increase of fever in Glasgow, which 
 has steadily been going on since 1816, principally "to the total 
 want of cleanliness among the lower orders of the community, to 
 the absence of Ventilation in the more densely peopled districts, and 
 
 1 Tweedie's Clinical Illustrations of Fever, p. 78. 2 lb. p. 80. 
 
 3 Armstrong on Typhus Fever, p. 8. 
 
 4 Edinburgh Medical and Surgical Journal, vol. xxviii, p. 236 
 
DAVIDSON ON THE CAUSES OP FEVER. 59 
 
 to the accumulation for weeks or months together of filth of every 
 description in our public and private dunghills ; to the over- 
 crowded state of the lodging-houses resorted to by the lowest 
 classes; and to many other circumstances unnecessary to men- 
 tion." 1 The same author, in another part of his statistics, illustrates 
 the causes which tend to render fever epidemic ; and he makes the 
 following observations: "From the close of 1836, one of those 
 periodical depressions in trade, arising from the state of our mone- 
 tary system, has visited this city, and deprived a large proportion 
 of the population of the means of subsistence. From the existence 
 of secret combinations among the working classes in various de- 
 partments of trade, but especially amonsf the cotton spinners, and 
 the 'strikes' which resulted from these combinations, a very large 
 proportion of the inhabitants, in addition to those already suffering" 
 from the state of the money market, were suddenly deprived of em- 
 ployment, and consequently of the means of procuring food. The 
 high price of coal was the means of diminishing the hours of 
 labour, and consequently the amount of wages, in numerous facto- 
 ries, and placed fuel beyond the reach of the lower classes for do- 
 mestic purposes. And in addition to these sources of misery, the 
 average prices of grain were much higher during 1837 than they 
 had been for some years previously. 3 ... A reference to the 
 tables of the state of the weather given in the preceding part of this 
 paper, will show the quantity of rain which fell, monthly, during 
 the period of my attendance on the Fever Hospital, and the average 
 temperature indicated by Fahrenheit's thermometer. From these 
 it appears that the quantity of rain was much above the average, 
 while the temperature of almost every month was lower than that 
 of the previous year; and while the mean heat of Glasgow is 4,7° 
 75, the mean heat of 1835 was 46° 58, and that of 1836 only 
 44° 52. 3 
 
 li The number of fever patients treated in Hospital in 1837, was . 53S7 
 " " 1836 " . 3125 
 
 Being an increase in 1S37 of . . . . 2262 
 The number of fever patients treated by the district surgeons in 
 
 their own houses in 1837, was 2320 
 
 Ditto 1836, was 716 
 
 Being an increase of 1604" 
 
 The above table gives a very inadequate idea of the comparative 
 frequency of fever in 1836 and 1837. During 1836, till the month 
 of December, every applicant for admission was received into the 
 hospital : while in 1837, seldom a day passed without numerous 
 applicants being refused admission for want of room ; and many 
 were deterred from applying for admission from a knowledge, of the 
 over-crowded state of the wards. 4 Dr. Cowan calculates the num- 
 
 1 Cowan's Vital Statistics of Glasgow, p. 13. 
 ? Ibid. p. 33. * lb. p. 16. 
 
 * IK P . 37. 
 
60 DAVIDSON ON THE CAUSES OF FEVER. 
 
 ber of fever cases in Glasgow, during the years referred to, as fol- 
 lows : 
 
 "In 1835 6.180 
 
 1836 10.092 
 
 1837 21.800 
 
 38.072" 1 
 
 After having given a table of the deaths from fever during each 
 month of the years 1836 and 1837, the same author makes the fol- 
 lowing deductions from it. " Many interesting observations may 
 be drawn from this table. It shows the slow progress of an epi- 
 demic disease when trade is prosperous, compared with what occurs 
 in seasons of distress. Up to November, 1836, the period at which 
 the commercial embarrassments were felt, the mortality from fever 
 had not been rapidly increasing. In November it was just about 
 double what it had been in January preceding, the number of 
 deaths being forty-five in January, and eighty-nine in November. 
 The moment, however, the effects of the stagnation in trade ex- 
 tended to the working classes, the mortality increased with fearful 
 rapidity, aided, no doubt, by the season of the year, the high price 
 
 of grain, and the scarcity or high price of fuel The 
 
 table also marks the period at which the epidemic reached its maxi- 
 mum amount of mortality, namely, in the second quarter of 1837, 
 and in the month of May in that quarter, being the month succeed- 
 ing that in which the strike of the cotton spinners took place, by 
 which 8000 individuals were thrown out of employment." 2 The 
 total quantity of rain, according to Dr. Cowan, which fell during 
 1837, as ascertained at the University of Glasgow, was 26.629 in- 
 ches ; and the mean temperature for that year was 46° 31. 3 
 
 We have constructed the following tables from the registers of 
 the weather and the table of deaths from fever in Glasgow, as given 
 in Dr. Cowan's work, in order to show, that though the increased 
 quantity of rain during the years 1836 and 1837 was influential in 
 the diffusion of fever, yet that it had less effect in spreading the 
 epidemic than other causes; for during the year 1837, at which 
 time it had reached its maximum, the total quantity of rain that fell 
 was less than during 1836, while the average temperature of these 
 two years did not materially differ from each other. 
 
 1 Cowan's Vital Statistics of Glasgow, p. 38. * lb. p. 39. 3 lb. p. 35. 
 
DAVIDSON ON THE CAUSES OF FEVER. 
 
 61 
 
 1836. 
 
 Deaths from fever 
 
 Mean temperature 
 
 Quantity of Rain. 
 
 January . . . 
 
 45 
 
 37°84 
 
 3.868 
 
 February 
 
 
 
 27 
 
 35 39 
 
 0.732 
 
 March 
 
 
 
 57 
 
 38 60 
 
 2.375 
 
 April . . . 
 
 
 
 64 
 
 42 05 
 
 L.098 
 
 May . . 
 
 
 
 67 
 
 51 04 
 
 0.173 
 
 June . . . 
 
 
 
 71 
 
 55 19 
 
 1.812 
 
 July . . 
 
 
 
 61 
 
 54 38 
 
 4.536 
 
 August . 
 
 
 
 82 
 
 53 17 
 
 5.317 
 
 September 
 
 
 
 56 
 
 47 37 
 
 2.134 
 
 October . 
 
 
 
 89 
 
 42 89 
 
 4.988 
 
 November 
 
 
 
 89 
 
 38 11 
 
 2.004 
 
 December 
 
 
 
 133 
 ! 841 Total. 
 
 38 27 
 
 2.673 
 
 1837. 
 
 2 44.52 Aver. 
 
 8 31.710 Total. 
 
 
 
 January . . . 
 
 201 
 
 36° 13 
 
 1.956 
 
 February 
 
 
 
 138 
 
 40 55 
 
 2.674 
 
 March 
 
 
 
 224 
 
 34 39 
 
 1.500 
 
 April . . 
 
 
 
 202 
 
 38 28 
 
 1.646 
 
 May . . 
 
 
 
 233 
 
 48 21 
 
 1.857 
 
 June . . 
 
 
 
 199 
 
 56 89 
 
 2.241 
 
 July . . 
 
 
 
 194 
 
 60 80 
 
 3.322 
 
 August . 
 
 
 
 172 
 
 56 90 
 
 2.610 
 
 September 
 
 
 
 126 
 
 52 99 
 
 1.570 
 
 October . 
 
 
 
 149 
 
 48 92 
 
 2.997 
 
 November 
 
 
 
 147 
 
 39 68 
 
 2.293 
 
 December 
 
 
 
 195 
 4 2180 Total. 
 
 41 95 
 
 1.963 
 
 
 
 
 5 46.31 Aver. 
 
 6 26.629 Total. 
 
 The number of deaths from fever in a given period is not an 
 exact criterion of the number of persons affected ; for the intensity 
 of this disease varies considerably at different seasons of the year; 
 but as the number of deaths which occurred in each month of 1836 
 and 1837 respectively, are given, the relative mortality will give a 
 pretty near approximation to the relative number affected. 
 
 Dr. Arthur Thomson, in his Statistics of Fever, has given two 
 tables, which show the influence of the seasons on the prevalence 
 of fever; and as his conclusions are drawn from a large number 
 of cases, they are well adapted for illustrating this part of the sub- 
 ject. 
 
 1 Cowan's Statistics of Glasgow, p. 38. 
 3 lb. p. 4. * lb. p. 38. 
 
 * lb. p. 5. 
 6 lb. p. 35. 
 
62 
 
 DAVIDSON ON THE CAUSES OP FEVER, 
 
 " Table XII. Showing the maximum, minimum, and m,ean temperature 
 in Great Britain during each month, from the observations of about 
 thirty years together with the average monthly quantity of rain in 
 inches from thirty -four years'' observations (from 1797 to ]830.) 1 
 
 Months. 
 
 January . 
 February 
 March . 
 April 
 May . . 
 June . . 
 July . . 
 August . 
 September 
 October . 
 November 
 December 
 
 Mean 
 
 Average 
 
 temperature. 
 
 quantity of rain 
 in inches. 
 
 36° 
 
 1.90 
 
 38 
 
 1.49 
 
 43 9 
 
 1.39 
 
 49 9 
 
 1.84 
 
 54 
 
 2.00 
 
 58 7 
 
 1.94 
 
 61 
 
 2.55 
 
 61 
 
 2.15 
 
 57 
 
 2.29 
 
 48 
 
 2.41 
 
 42 
 
 2.79 
 
 39 
 
 2.58 " 2 
 
 From the above it appears that July and August are the months 
 during which the average temperature is greatest, and that the 
 quantity of rain falling during the last six months of the year is 
 considerably more abundant than during the first six. The follow- 
 ing table this author has "compiled from materials selected indis- 
 criminately from all the reports which he could obtain, showing 
 the number of fever cases admitted into the various hospitals in 
 Great Britain and Ireland; but he is chiefly indebted to Drs. Barker 
 and Cheyne's account of the epidemic fever which prevailed in 
 Ireland in 1817-18-19." 
 
 " Table XIII. Showing that of 51,944 cases of fever admitted into dif- 
 ferent hospitals in Great Britain and Ireland, the number and relative 
 ratio of admissions in each month were as follow : 
 
 Months. 
 
 No. of Cases 
 
 Relative ratio of ad- 
 
 
 admitted. 
 
 missions per cent. 
 
 January .... 
 
 2895 
 
 5.6 
 
 February 
 
 
 
 
 2825 
 
 5.4 
 
 March 
 
 
 
 
 3152 
 
 6.1 
 
 April . . 
 
 
 
 
 3374 
 
 6.5 
 
 May . . 
 
 
 
 
 3990 
 
 7.6 
 
 June . . 
 
 
 
 
 4365 
 
 8.3 
 
 July . . 
 
 
 
 
 4999 
 
 9.6 
 
 August . 
 
 
 
 
 5261 
 
 10.1 
 
 September 
 
 
 
 
 5046 
 
 9.7 
 
 October . 
 
 
 
 
 5624 
 
 10.8 
 
 November 
 
 
 
 
 5054 
 
 9.7 
 
 December 
 
 
 
 
 5359 
 
 10.6 
 100.0 
 
 
 
 
 
 Total 51,944 
 
 1 The maximum and minimum temperature is omitted. 
 
 2 Howard on Climate of London, 2d Edit. Vol. i. p. 136. 
 
DAVIDSON ON THE CAUSES OF FEVER. 
 
 63 
 
 "It appears from this table that the greatest number of fever 
 cases were admitted into the different hospitals, during the last six 
 months of the year, or from July to December. And the number 
 of cases admitted from January to June are few, compared with 
 the admissions from July to December." 1 
 
 In order to compare the number of admissions in each month, 
 with its mean temperature and average quantity of rain, we shall 
 construct a table out of the two that have just now been quoted ; 
 which will show the number of admissions, the mean temperature, 
 and the average quantity of rain for each month. 
 
 Months. 
 
 No. of Cases 
 admitted. 
 
 Mean 
 Temperature. 
 
 Average 
 
 quantity of rain 
 
 in inches. 
 
 January . . 
 February . . 
 March . . . 
 
 2895 
 2825 
 3152 
 
 36° 
 38 
 43 9 
 
 1-90 
 1-49 
 1-39 
 
 April . . . 
 May . . . 
 June . . . 
 
 3374 
 3990 
 4365 
 
 49 9 
 54 
 
 58 7 
 
 1-84 
 2-00 
 1-94 
 
 July . . . 
 August . . 
 September 
 October . . 
 
 4999 
 5261 
 5046 
 5624 
 
 61 
 61 , 
 
 57 
 48 
 
 2-55 
 2-15 
 229 
 2-41 
 
 November 
 
 5054 
 
 42 
 
 2-79 
 
 December 
 
 5359 
 
 39 
 
 2-58 
 
 51,944 
 
 This table shows that the greatest number of fever cases were 
 admitted into the various hospitals from July to December, or dur- 
 ing the last six months of the year; and that during this period the 
 average quantity of rain which falls is much greater than during 
 the first six months of the year. If we compare any one month of 
 the last six with any one month of the first, there will be found a 
 similar difference. The same table also shows that the temperature 
 may vary considerably during a similar prevalence of fever, and 
 that nearly the same temperature may prevail with a great varia- 
 tion in the number of cases. Thus, in August the number of cases 
 is 5261, and in December the number of cases is 5359, being a 
 difference only of 98; but the mean temperature of the first-men- 
 tioned month is 61°; while that of December is only 39°; the 
 quantity of rain, however, in both of these months is above the 
 average. In March the mean temperature is 43° 9, and the number 
 of cases 3152; while in November the mean temperature is 42°, 
 and the number of cases 5054; but the quantity of rain in March is 
 1° 39, while in November it is 2° 79, being double the amount of 
 that which falls in the first-mentioned month. In February the 
 mean temperature is 38°, and the number of cases 2825 ; while in 
 
 1 Edinburgh Medical and Surgical Journal. July, 1838. p. 100, 
 
64 DAVIDSON ON THE CAUSES OF FEVER. 
 
 December the mean temperature is 39°, and the number of cases 
 5359; but the quantity of rain in the first of these months is 1*49 
 inches, while in December it is 2-58 inches. 
 
 The conclusions which may be drawn from this table, are, that 
 in all the months in which the quantity of rain is above the 
 average, fever prevails to a greater extent than in those months in 
 which it is below this point. It does not appear, however, from it 
 that the average range of temperature of this climate has much 
 influence on the prevalence of fever; for if moisture be present, it 
 may prevail to about the same extent, when the average tempera- 
 ture is 61°, as in August, or when it is 39°, as in December. 
 
 The diffusion of fever is thus generally connected with humidity 
 of the atmosphere; yet certainly there are other causes of a more 
 influential kind that are also in operation. This is well exemplified 
 by the two tables (page 52), which show the prevalance of fever 
 and the corresponding weather in Glasgow during the years 1836 
 and 1837. Thus, although in both of these years the quantity of 
 rain was greater than the average, and in the first of them greater 
 than in the second, yet the number affected with fever during 1836 
 amounted only to about the half of those that were seized during 
 1837. The increased prevalence of the epidemic during 1837, 
 must, to a very considerable extent, have depended upon the 
 scarcity of provisions, want of fuel, &c, and their concomitants, 
 filth, &c, which followed the commercial embarrassments of that 
 year. 
 
 An accumulation of persons not previously affected tends to 
 diffuse typhus. There is also another important point connected 
 with the history of eruptive typhus, which has seldom been taken 
 into calculation in attempting to account for its diffusion, namely, 
 that it does not often attack the same person more than once dur- 
 ing his life. Now if this be admitted, — and we have endeavoured 
 to show at page 19, the analogy between typhus and other exan- 
 thematous fevers in this particular, but even though M. Hilden- 
 brand's modified view only be granted, namely, that it secures the 
 person who has been affected only for some years — it follows: 
 
 1st. That after an epidemic fever has prevailed for some time, it 
 must cease after the lapse of a particular period, from deficiency of 
 material to act upon ; and the history of almost every pestilence of 
 this kind, shows that it rarely exceeds two years in duration, even 
 in a large city. 
 
 2d. That, "though fever may constantly exist in a large town, in 
 a minimum proportion, varying in numbers according to the habits 
 of the people, those who have never laboured under the disease are 
 gradually accumulating; and that when the state of the atmo- 
 sphere, as to humidity, and the scarcity of provisions, with their 
 consequents, filth and deficient ventilation, are concurrent with 
 this accumulation of susceptible individuals, that fever has rarely 
 failed to spread among the community. And if the population of 
 any large city be increasing very rapidly, such as that of Glasgow, 
 
DAVIDSON ON THE CAUSES OF FEVER. 65 
 
 at the rate of ten thousand persons annually, the number of sus- 
 ceptible individuals will be accumulated in a few years to an 
 amount, sufficient for the existence of an extensive epidemic. 
 
 3d. That a severe epidemic fever of one or two years' duration 
 is never succeeded by another until several years have elapsed. 
 
 A very important inquiry may be deduced from the foregoing 
 statements. Can the very rapid increase of the population of Glas- 
 gow account, to a greater or less extent, for its being visited for a 
 series of past years with more frequently recurring epidemics of 
 fever than any other city of Great Britain, similar in size and popu- 
 lation ? Can the influx of several thousands of unprotected indivi- 
 duals from the country every year afford any explanation of the 
 occurrence; jnst as there is always a great mortality from smallpox 
 in Glasgow, from the influx of unvaccinated Highlanders, while in 
 many other cities of the kingdom this disease is comparatively 
 rare? There can be no doubt that the influx of so many strangers 
 to this city must have a powerful effect in increasing the number 
 of fever patients ; but certainly the filthy and irregular habits of its 
 working population are equally operative as predisponents to con- 
 tagion. Is there then any prophylactic measure which may either 
 ward off or diminish the extent of an epidemic diffusion of fever in 
 a large city ; or is this beyond the control of human means and 
 calculations? We think not; although we do not entertain the 
 notion that fever will ever be completely extinguished in any large 
 manufacturing town ; or that the spread of it, epidemically, can be 
 checked in limine, when the concurrent circumstances are favour- 
 able for its propagation ; but certainly much might be done to 
 lessen the intensity of the evil. It has already been shown that 
 filth and deficient ventilation tend much to spread the contagion of 
 typhus, being almost constant concomitants ; and that while it 
 generally affects the whole members, or the large proportion of a 
 family, among the lower orders, it rarely spreads in this manner 
 among the better classes of society, who attend more to cleanliness 
 and ventilation. It is quite obvious that an amelioration of the 
 physical condition of the lower orders, in these particulars, would, 
 in proportion as this was effected, diminish their chances of catch- 
 ing the contagion ; which would not only operate in lessening 
 directly its diffusion, but, by reducing the number of its sources, 
 must tend to lessen the actual quantity of this principle that might 
 be generated in a given time. 
 
 But can this amelioration be effected to any appreciable extent ; 
 or if effected, could it be maintained for any length of time ? We 
 fear that little permanent amelioration could be effected without a 
 legislative enactment; for though our philanthropists are very 
 active in their charities during the prevalence of an epidemic, it no 
 sooner, subsides than they relapse into a comparative quiescence, 
 and our working population into their former habits of filth and 
 intemperance. And the evil will continue to assail us so long as 
 our cities contain so many narrow and filthy lanes, so long as the 
 4 — a 5 dav 
 
66 DAVIDSON ON THE CAUSES OF FEVER. 
 
 houses situated there are little better than dens or hovels, so long 
 as dunghills and other nuisances are allowed to accumulate in 
 their vicinity, so long as these hovels are crowded with inmates, 
 and so long as there is so much poverty and destitution. Why, then, 
 should we not have a legislative enactment that would level these 
 hovels to the ground, that would regulate the width of every street, 
 that would regulate the ventilation of every dwelling-house, that 
 would prevent the lodging-houses of the poor from being crowded 
 with human beings, and that would provide for their destitution? 
 It may be said, that this would interfere too much with the liberty 
 of the subject, and no doubt it would be vehemently opposed by 
 many interested persons. In place, however, of being an infringe- 
 ment on the liberty of the subject, it might rather be designated an 
 attempt to prevent the improper liberties of the subject ; for what 
 right, moral or constitutional, has any man to form streets, con- 
 struct houses, and crowd them with human beings, so as to dete- 
 riorate health and shorten life because he finds it profitable to do 
 so? As well ought the law to tolerate the sale of unwholesome 
 food, because it might be profitable to the retailer of it. 
 
 CHAPTER III. 
 
 Circumstances which tend to render fevers communicable from one person to another. 
 
 It is quite obvious, if the doctrine of contagion be admitted, that 
 all those circumstances which favour the diffusion of fevers tend 
 also to render them communicable from one person to another ; it 
 is therefore necessary to include them in the following arrange- 
 ment, although it seems only necessary to illustrate one of them a 
 little farther, namely, the influence of filth and deficient ventilation. 
 
 Circumstances which tend to render fevers communicable : 
 
 1. Humidity of the atmosphere. 
 
 2. Scarcity of provisions, &c. 
 
 3. No previous affection with typhus. 
 
 4. Filth and deficient ventilation. 
 
 5. Age. 
 
 6. Acclimatization. 
 
 7. Idiosyncrasy of constitution. 
 
 Alleged circumstances which tend to render fevers communicable: 
 
 1. Weakness of constitution. 
 
 2. Greater susceptibility of females. 
 
 3. Depressing passions. 
 
 4. Intemperance. 
 Alleged exemptions from fever : 
 
 1. Prom trade or occupation. 
 
 2. From chronic diseases. 
 
DAVIDSON ON THE CAUSES OF FEVER. 67 
 
 These different points shall be considered in the following part 
 of the essay, though not exactly in the order enumerated, as this 
 might derange the general connection of the observations. 
 
 Influence of filth and deficient ventilation. In a previous part 
 of the essay we entered into the consideration of filth and deficient 
 ventilation as tending very powerfully to spread the contagion of 
 typhus; and showed that, where it was concentrated, as in crowded 
 hospitals, or in the small and ill-ventilated houses of the lower 
 classes, it rarely failed to be communicated to the unprotected 
 attendants or inmates of a family. Filthiness of personal habits, 
 however, although it tends to render it more communicable, as we 
 shall endeavour to show from the statistics of the Glasgow Fever 
 Hospital, does not seem to act so powerfully in this respect as defi- 
 cient ventilation, which by concentrating the contagion may render 
 its operation on the system more certain. In proof of which we 
 may quote the various attendants of our fever hospitals, who are 
 generally very attentive to cleanliness in their persons, and yet, if 
 unprotected, are almost uniformly affected with fever during some 
 period of their attendance, if the wards be in a crowded state. This 
 fact, and the more frequent exemption of the attendants when the 
 wards are moderately filled and well ventilated, seem to prove that 
 contact with the patient is not so essential for the communication 
 of the disease, as being surrounded by an atmosphere highly im- 
 pregnated with the contagious miasmata. And there are many 
 instances where students have been affected with fever after visit- 
 ing the wards of an hospital, without having come into contact 
 with the patients or their bed-clothes. There can be no doubt, 
 however, that simple contact of a typhus patient, or of clothes that 
 have been attached to him in any shape, may communicate the 
 disease without the aid of even a partial impregnation of the atmo- 
 sphere with contagious effluvia, and where the most perfect venti- 
 lation has been maintained. 
 
 ' We are at present unacquainted with the channel by which the 
 contagion of typhus most generally enters the body; and though 
 the opinion be generally entertained that the lungs are the organs 
 through which it passes into the system, yet it is equally probable 
 and consistent with analogy and facts to believe, that the skin is, at 
 least, as important as a medium of communication. There are 
 many animal poisons that operate on the system through the skin 
 very powerfully, and yet have little effect when applied to the 
 mucous membrane of the stomach or intestines; now though, in 
 the one case, the poison operated with be ponderable and be applied 
 to the mucous surface of the stomach and bowels, while, in the 
 other case, the contagion of typhus is imponderable, and is applied 
 to the mucous surface of the bronchial tubes, yet, in the absence of 
 direct experiment, this analogy is entitled to some consideration. 
 
 The following tables will tend to show that filthiness in personal 
 habits is very frequently connected with the production of typhus, 
 and it includes all the cases of fever that were admitted into the 
 
 5* 
 
68 
 
 DAVIDSON ON THE CAUSES OF FEVER. 
 
 Glasgow Fever Hospital from May 1st to November 1st, 1839, in 
 whom their state as to cleanliness or filthiness was ascertained : l 
 
 Scotch 
 
 Irish 
 
 English . . . , . 
 West Indies and North 1 
 America ... 5 
 
 FILTHY. 
 
 Males. Females. 
 
 92 
 
 88 
 4 
 
 187 
 Total filthy...340 cases 
 
 81 
 
 70 
 
 2 
 
 153 
 
 CLEAN. 
 
 Males. Females. 
 
 64 
 
 60 
 
 3 
 
 127 
 
 93 
 
 47 
 
 3 
 
 144 
 
 Total clean.. .271 cases. 
 
 The following table shows the number of cases that were filthy 
 and those that were clean in typhus characterised by the eruption, 
 and also the proportions, regarding this point, which were ascer- 
 tained in febricula ; 
 
 FILTHY. 
 
 Males. Females. 
 
 Eruptive typhus 133 112 
 
 Febricula . . 6 8 
 
 Total no. of cases of febricula filthy 14 
 
 of typhus — ...245 
 
 CLEAN. 
 
 Males. ] Females. 
 
 73 
 19 
 
 77 
 15 
 
 Total no. cases of febricula, clean.. 34 
 of typhus — ..150 
 
 These two tables show that among 611 cases admitted as con- 
 tinued fever, there were 340 filthy and 271 clean, or about fifty-five 
 per cent, filthy ; that among 395 cases of eruptive typhus, there 
 were 245 filthy and 150 clean, or about sixty-two per cent, filthy ; 
 and that among forty-eight cases of febricula, there were fourteen 
 filthy and thirty-four clean, or about twenty-nine per cent filthy. 
 The following deductions may be drawn from these facts. 1. That 
 the proportion of filthy persons is greater than that of the clean 
 among the whole number of cases admitted, and including not 
 only typhus, but bronchitis, febricula, pneumonia, and several other 
 affections which are specified in a table already given. 2. That 
 among the eruptive or decided cases of typhus, the proportion of 
 the filthy to the clean is still greater than what exists among the 
 whole number of cases. 3. That among the cases of febricula, the 
 proportion of filthy persons is only twenty-nine per cent., while in 
 eruptive typhus it is sixty-two per cent. 4. That, as the propor- 
 tion of filthy persons in the whole number of cases is less than in 
 those affected with eruptive typhus, it is fair to infer that this is 
 owing to an admixture, with the latter, of febriculous, bronchitic 
 cases, &c, since it has been shown that filthiness is much less fre- 
 
 1 The reports, respecting the clean or filthy state of the patients admitted, 
 were taken by the barber of the Fever Hospital, and afterwards transferred 
 by the author, along with other statistical facts, into his own journal. 
 
DAVIDSON ON THE CAUSES OF FEVER. 69 
 
 quently a concomitant of febricula, &c, than it is of eruptive 
 typhus. 
 
 We are entirely ignorant of the nature of those substances which 
 absorb the typhus contagion with most facility; but, as filth is very 
 frequently a concomitant of its ready communicability, it may be 
 assumed that either the clothes or the deposits on the skin of filthy 
 persons have a tendency to absorb the contagion and to retain it 
 until the system become affected. We know that certain gases, 
 and even odours and fetid effluvia, are absorbed more readily by 
 some substances than by others ; and though we are only warranted 
 to assume from this analogy, that typhus contagion is very probably 
 regulated by a similar law, yet, on the other hand, if want of clean- 
 liness facilitate the operation of contagion on the system, it is not 
 possible to explain this effect on the principle of pulmonary inhala- 
 tion, while the theory of cutaneous absorption is not opposed by 
 any fact or analogy. If this view be adopted, it will obviously lead 
 to a prophylactic measure of considerable importance, namely, the 
 daily and thorough ablution of the skin, and the frequent changing 
 of the wearing apparel ; for it is not probable that the contagion will 
 be absorbed immediately after its application to the clothes or skin 
 of the person who has been exposed to it; and by the daily ablution 
 of the whole body, it may be removed before this can occur. 
 
 Influence of idiosyncrasy of constitution. — The contagion of 
 typhus is not communicable to all persons with the same facility. 
 Some individuals are infected after the first exposure, while others 
 maybe exposed for weeks, or even many months, almost constantly, 
 before they are attacked. It may be said, however, that in this last 
 case the contagion has remained for a longer time latent than in 
 the former. There is no very precise evidence existing as to this 
 point, and the opinions entertained by many authors are often con- 
 jectural. Dr. Bancroft states as follows: "It results, therefore, 
 from this statement, that among the ninety-nine orderlies and 
 nurses who had probably not been exposed to the contagion before 
 their attendance on the sick commenced, the earliest attack was on 
 the thirteenth day, and the latest on the sixty-eighth ; but these 
 returns were made up about the 20th of April, and it appears that 
 some who had escaped till that time were afterwards attacked; and 
 therefore, though there may be reason to conclude that febrile con- 
 tagion does not remain inactive so long after being received into 
 the body as marsh miasmata, I see none for believing that an inter- 
 val of five or six months may not sometimes elapse before the 
 actual production of fever by it," 1 Dr. Perry is of opinion, that 
 " the earliest period of the disease making its appearance after ex- 
 posure to contagion is eight days, more frequently fourteen, and 
 sometimes so long as two months." 2 What the circumstances are 
 which render some persons, who enjoy good health, are well fed 
 
 1 Bancroft on Yellow Fever, &c. p. 516. 
 
 2 Edinb. Med. and Surgical Journal, vol. xlv. p. 69. 
 
70 DAVIDSON ON THE CAUSES OP FEVER. 
 
 and cleanly in their personal habits, more susceptible of contagion 
 at one period than at another are totally unknown ; but we are in 
 the same state of ignorance as to the reason why scarlet fever, &c., 
 may be caught at one period and not at another, and why vaccina- 
 tion frequently succeeds at last after five or six unsuccessful trials. 
 Again, a certain proportion of persons appear not to be susceptible 
 of the disease. Dr. Perry is the only author that we are acquainted 
 with that enumerates the proportions of susceptible and non-sus- 
 ceptible individuals. His tenth proposition is the following: "That 
 between the ages of seven and fifty, sixteen out of twenty are sus- 
 ceptible of being affected with contagious typhus, if exposed to the 
 contagion, and not protected by having previously had the disease." 1 
 
 That there is a certain proportion of individuals who are not 
 susceptible of typhus contagion there can be no doubt, for there are 
 many medical practitioners and nurses of fever-hospitals who have 
 never laboured under the disease, although they have been exposed 
 to its influence for many years, but there is no proof that in the 
 present state of our fever statistics we can define the proportion of 
 unsusceptible persons. It is a common opinion that constant 
 exposure lessens the susceptibility to fever ; but this, in the present 
 state of our knowledge, can only be considered as a probable hypo- 
 thesis. 
 
 Influence of sex. — Hildenbrand is of opinion that delicate men, 
 who have a fine skin and feeble bodies, are most subject to conta- 
 gion ; while, on the contrary, those that are robust, plethoric, vigor- 
 ous, and well nourished, more seldom contract it. These opinions 
 are entertained by several writers on fever; and for a similar rea- 
 son, it is sometimes concluded that females are more subject to this 
 disease than males. It is natural for an author, who advocates the 
 absorption of contagion by the skin, such as Hildenbrand, to infer 
 that a fine skin, like that of the female, will absorb more readily 
 than one which is coarse; and although this theory be supported 
 by the statistics of some hospitals, it is opposed by those of others. 
 The number of admissions into the Glasgow Fever Hospital dur- 
 ing the year 1836 were 1116 males and 1141 females, 2 which is 
 only a small excess of females ; but if the excess of the female over 
 the male population of Glasgow be taken into the account as about 
 one sixth, the proportion of males that have been affected with 
 fever will be plus instead of minus. In the same institution were 
 admitted, from May 1st to November 1st, 1839, 270 males and 276 
 females, classified under typhus. Into the Cork-street Fever Hos- 
 pital, Dublin, from 5th January, 1817, to 30th April, 1818, there 
 were admitted 2883 males and 2849 females, which is a small 
 excess of males. 3 Again, in other hospitals, there has occurred an 
 excess of females. There were admitted into the Waterford Hos- 
 
 1 Edinb. Med. and Surgical Journal, vol. xlv. p. 67. 
 
 8 Cowan's Vital Statistics, p. 19. 
 
 3 Barker and Cheyne on Fever, vol. i. p. 91. 
 
DAVIDSON ON THE CAUSES OF FEVER. 71 
 
 pital 1277 males and 1452 females, 1 into the London Fever Hospital 
 1229 males and 1308 females, 2 into the Limerick Fever Hospital 
 1332 males and 1895 females, being a large excess of females, 3 and 
 into the Edinburgh Royal Infirmary 962 males and 1075 females. 4 
 The facts which have been hitherto published regarding the sus- 
 ceptibility of the different sexes to fever are not yet sufficiently 
 extended to warrant us drawing any certain conclusion from them; 
 but certainly it does not appear to be established by satisfactory 
 evidence, that the one sex is more liable to the disease than the 
 other; and, where this does occur in any particular place, that it 
 cannot be accounted for by the general excess of female population 
 in large cities, or by other circumstances connected with their his- 
 tory. Drs. Barker and Cheyne remark, that " in Dublin, when the 
 epidemic had completely established itself, the males admitted to 
 hospital were most numerous, but in its progress the admissions of 
 females exceeded those of males As to the comparative fre- 
 quency of fever in the male and female sex in the country at large, 
 we can form no decisive opinion, the answers to our inquiries on 
 that head not having been perfectly satisfactory." 5 
 
 Although the comparative frequency of fever among the sexes 
 has not been accurately determined, it has beea proved satisfacto- 
 rily by the statistics of almost every large hospital, that a larger per 
 cent, of males than of female patients die of the disease ; and it is 
 proved by the Glasgow Mortality Bills, that a much greater num- 
 ber of the male than of the female population of that city are car- 
 ried off by it. Thus, in Glasgow, during the year 1836, 465 males 
 and 376 females died of fever; during 1837, 1187 males and 993 
 females ; and during 1838, 439 males and 377 females. 6 If the 
 average mortality of each sex could be accurately ascertained, this 
 large amount of deaths might be made available for determining 
 the liability of the different sexes to lever, by the same method of 
 approximation which Dr. Cowan has adopted in calculating the 
 amount offerer in Glasgow during the years 1836 and 1837 ; 7 but 
 as the proportionate mortality of the different sexes is not the same 
 during every season, and as it may not be the same among those 
 treated at home as in those treated in hospitals, this method, al- 
 though well adapted for giving a general approximation, is not well 
 calculated for determining a nice question of this kind. 
 
 Influence of delicacy, or tveakness of constitution, — We have 
 already remarked, that it is a prevalent opinion among medical 
 
 1 Barker and Cheyne on Fever, vol. i. p. 193. 
 8 Dr. S. Smith's Treatise on Fever, p. 432. 
 
 3 Dr. Geary's Report, Dublin Journ. of Med. Science, vol. xii. p. 10. 
 
 4 Edinb. Med. and Surg. Journal, Oct. 1839, p. 448. 
 
 5 Barker and Cheyne on Fever, pp. 89-90. 
 
 6 Glasgow Bills of Mortality for 1836, 1837, and 1S38. 
 
 7 Dr. Cowan estimated the proportion of the whole mortality in 1837 as 
 one in every ten patients; and to determine the amount of cases, multiplied 
 the whole number of deaths, which were 2180 by 10= 21,800. 
 
72 
 
 DAVIDSON ON THE CAUSES OP FEVER. 
 
 men, that persons naturally weak and delicate are more liable to 
 fever than those who are healthy and vigorous. This opinion 
 seems to be as little capable of proof as the preceding one regarding 
 the greater liability of females to the disease. We are not, however, 
 in possession of much evidence, and none statistical, so far as we 
 are aware, regarding this point, beyond the loose and general ob- 
 servations of authors. 
 
 We have kept a record of the physical habit of the patients ad- 
 mitted into the Glasgow Fever Hospital from May 1st, to November 
 1st, 1839, and the following were the divisions adopted : 
 
 1. Moderate, by which is meant a person having an ordinary 
 quantity of muscle and cellular substance. 
 
 2. Full or plethoric, having an extra quantity of adipose texture 
 or of blood. 
 
 3. Muscular. 
 
 4. Spare. 
 
 5. Emaciated or unhealthy in appearance. 
 
 Full or plethoric . . . 
 Unhealthy or emaciated . 
 
 Males. 
 
 Females. 
 
 Total, 
 
 116 
 
 28 
 
 44 
 
 24 
 
 2 
 
 93 
 73 
 
 41 
 
 8 
 
 209 
 
 101 
 
 44 
 
 65 
 
 10 
 
 429 
 
 The whole of these 429 cases were characterised by the typhoid 
 eruption, and will therefore be considered as decided cases of 
 typhus. It appears from this table, that there were only ten cases 
 in an emaciated or unhealthy condition ; and almost all of them, as 
 far as could be ascertained, were engaged in their ordinary occu- 
 pations at the time of their seizure. The spare and unhealthy, 
 when added together, only form about 17 per cent, of the whole 
 number. 
 
 Influence of chronic diseases. — The evidence, such as we have 
 collected from the previous history of patients admitted into the 
 Glasgow Fever Hospital, and from post mortem examinations, 
 seems to prove that persons affected with any particular chronic 
 disease of the chest or belly, are very rarely affected with typhus 
 fever. Hildenbrand states that phthisical persons are very rarely 
 affected with typhus fever ; and that, out of many hundred cases 
 of this disease that he has treated, not one instance of a phthisical 
 person has occurred. We have heard the same opinion expressed 
 by several physicians of extensive hospital experience, and that 
 they have scarcely ever met with a case of tubercles in a person 
 who has died of eruptive typhus. 
 
 This opinion we can nearly confirm from our own experience, 
 
DAVIDSON ON THE CAUSES OF FEVER. 73 
 
 for out of more than 100 post mortem inspections we have met with 
 only three cases ; and the number of tubercles in each did not ex- 
 ceed three, which were small and only partially softened. 
 
 Influence of fear and the depressing passions. — The influence 
 of fear and the depressing passions has also been considered as 
 very powerful in predisposing persons to be affected with typhus 
 contagion. There can be no doubt that fear has a tendency to 
 produce a temporary depression of the physical powers ; but, as 
 has been already shown, there is no proof that persons of a natu- 
 rally spare or weak habit of body, who are generally very sensitive, 
 are more liable to fever than those of an ordinary constitution, this 
 opinion must also be considered hypothetical. Indeed, the facts, 
 as far as our inquiries have enabled us to judge, seem to prove that 
 the apprehension of fever, more particularly when it is not epidemic, 
 is very rarely felt until the person is actually seized with the dis- 
 ease ; for some cannot recollect of a single circumstance by which 
 they could be exposed to contagion ; and a considerable number of 
 those who had undoubtedly been exposed to it, were only made 
 aware of the fact when it had been elicited by cross examination. 
 We are quite aware that cases may be brought forward, of sensi- 
 tive individuals who have been seized with fever soon after visiting 
 a person labouring under the disease ; but as this fact can be op- 
 posed with at least an equal number of persons who were destitute 
 of fear, and yet caught it after an exposure to contagion, no conclu- 
 sion whatever can be drawn from them. It must be observed, 
 however, that though there is no proof that persons who are natu- 
 rally weak in body or of a sensitive disposition are more susceptible 
 of fever than those who are naturally vigorous and robust, yet 
 that, during famine or commercial distress, poverty by depressing 
 the mind and lowering the physical status from insufficient aliment, 
 does powerfully predispose a community to become affected with 
 fever. This has been already shown in a former part of the essay ; 
 and has been again alluded to, in order that the distinction might 
 be made between an individual of naturally weak mental and phy- 
 sical stamina, and one who has been reduced to that state by defi- 
 cient nutriment. 
 
 Influence of intemperance. — It is a question of vital importance 
 to the inhabitants of large towns, whether intemperance predis- 
 poses those who indulge in it to be affected with fever. A solution 
 of this point in a satisfactory manner cannot, we are afraid, be 
 made from our present data; for no statistics regarding it have 
 been published. Indeed, it is sometimes very difficult, even after 
 the most careful inquiries, to find out the habits of patients who are 
 sent to an hospital ; for most of them are ashamed to acknowledge 
 intemperance when it does exist, and those who admit that they in- 
 dulge a little are sometimes more abstemious, in point of quantity, 
 than those who deny any indulgence whatever. The ascertaining 
 of such habits, accurately, is in many cases impossible, and the 
 evidence must be viewed principally as an approximation to the 
 
74 DAVIDSON ON THE CAUSES OP FEVER. 
 
 truth. At the same time, this approximation may be often rendered 
 very convincing, by sifting the answers of the patients, by an at- 
 tentive examination of their appearance, and by the evidence of 
 friends ; and occasionally conclusions confirmatory of the opinion 
 formed may be drawn from their trade or occupation ; for it is well 
 known, that in some occupations the majority of the workmen are 
 addicted to excessive drinking. The frequent combination of drunk- 
 enness with lilthiness of personal habits is another circumstance 
 which complicates this question very materially, and renders the 
 appreciation of the value of each a matter of some difficulty. The 
 following table shows the proportion of temperate and intemperate 
 individuals, that were admitted into the Glasgow Fever Hospital 
 from November 1st, 1838, to November 1st, 1839, whose habits 
 could be ascertained with more or less certainty ; and the eruptive 
 cases are only included. 
 
 Temperate. A little Intemperate. Intemperate. 
 E. Typhus (Males) 125 51 73 
 
 E. Typhus (Females) 76 8 30 
 
 In this table the proportion of intemperate males is much greater 
 than that of the females. Can this circumstance account, to a 
 greater or less extent, for the greater mortality of the former in al- 
 most all hospitals ? It would be natural for a person, who wished 
 a certain theory supported, to conclude that as such a large number 
 of those^ affected with fever were reported to be more or less intem- 
 perate, this could not be an accidental and uninfluential concatena- 
 tion; but that the two circumstances must stand to one another, 
 in the relation of cause and effect. It would be necessary, how- 
 ever, before such an inference could be drawn, to ascertain whe- 
 ther the proportionate amount of the intemperate to the sober was 
 greater in the cases of fever than what existed among the commu- 
 nity from whom they were sent. We fear that this question can- 
 not be determined ; for the prevalence of intemperance among the 
 working population of large cities has been calculated principally 
 from the amount of drunkards that appear on our streets, from the 
 large and increasing number of our spirit shops, and from the enor- 
 mous quantity of ardent spirits consumed in a year. And though 
 there can be no doubt that drunkenness has increased among the 
 lower classes to a lamentable extent, its numerical amount has 
 never been ascertained, and perhaps never can be accurately ascer- 
 tained ; but certainly there are grounds for believing that the pro- 
 portion enumerated as intemperate, in the table which has been 
 given, is not greater than what really exists among the inferior 
 grades of our working population. A similar opinion is entertained 
 by Chomel, who states that alcoholic excesses appear to exert no 
 influence on the production of the typhoid fever. Intemperance, 
 however, tends indirectly to predispose the system to contagion, by 
 the production of filthy habits. It also exercises a most powerful 
 influence in increasing the mortality from fever. In the Glasgow 
 Fever Hospital there occurred eighty-one deaths from eruptive 
 
DAVIDSON ON THE CAUSES OF FEVER. 75 
 
 typhus in individuals whose habits were ascertained, and thirty- 
 four of these were reported as intemperate, nineteen a little intem- 
 perate, and twenty-eight temperate. In Dr. Craigie's table of the 
 deaths in thirty-one fever cases that occurred in the Edinburgh 
 Royal Infirmary, there are fifteen stated to be irregular or dissi- 
 pated, only two regular, the habits of the remainder are not stated. 1 
 
 It is also a singular fact, which has been noticed by several wri- 
 ters, that fever is more fatal among the higher than among the 
 lower classes. Dr. Braken states, in reference to the fever which 
 prevailed at Waterford during the years 1817-18-19, that "it 
 would be difficult to adjust the rates of mortality in the upper 
 classes, but it seems probable that one fourth or perhaps one third 
 of all those persons who were attacked with fever fell victims to its 
 power." 2 
 
 Drs. Barker and Cheyne, in their historical account of the Irish 
 epidemic, state that " in every part of the country fever was re- 
 ported to have been much more fatal amongst the upper than the 
 lower classes." 3 To what is this difference of mortality, so gene- 
 rally remarked by experienced hospital physicians, to be attributed? 
 and which in Ireland seemed to be very remarkable, namely, in the 
 lower classes about one in twenty-three cases, and among the upper 
 classes one in three or four generally, but in other places about one 
 in seven. Can the difference in the mode of living account for this 
 anomaly? as the first live very much on potatoes, while the other 
 use a larger or smaller proportion of animal food ; and the lower 
 classes almost every where in this country use less animal food and 
 stimulating dishes than those who are more wealthy and in a higher 
 sphere of society. 
 
 This subject is highly worthy of farther investigation ; for the 
 difference of mortality which exists among these different classes 
 most probably depends more upon some cause connected with their 
 habits and kind of aliment than upon their morale. 
 
 Influence of age. — Almost all modern authors who have written 
 on fever statistically state that the susceptibility to this disease is 
 greater among young persons than among the old ; and there is 
 sufficient evidence brought forward to establish this ; but certainly 
 the conclusions which have been drawn respecting the greater lia- 
 bility of one period of youth when compared with another have not 
 been satisfactorily proved. 
 
 From an examination of the ages of 117 patients, and by com- 
 paring his table with the results obtained by M. Louis and some 
 other observers, M. Chomel thinks it may be established that the 
 most common period of life for attacks of typhoid fever is from the 
 eighteenth to the thirtieth year ; that it is rarely observed beyond 
 
 1 Edinburgh Medical and Surgical Journal, vol. xlvii. p. 296. 
 8 Barker and Cheyne on Fever, vol. i. p. 277. 
 8 Barker and Cheyne on Fever, vol. i. p. 95. 
 
76 DAVEDSON ON THE CAUSES OF FEVER. 
 
 forty years ; and that perhaps no case has yet been observed where 
 the patient was beyond fifty-five years. 1 
 
 Dr. Cowan states that, " from an examination of these (his) tables, 
 it appears that the period of life at which fever is most liable to 
 occur is from the age of twenty to twenty-five years for the males, 
 when the proportion is 21.23 per cent., and from the age of fifteen 
 to twenty for females, when the proportion is 23.83 per cent." 2 Dr. 
 Geary, in his report of the Limerick Fever Hospital states, " that 
 children are much more liable to fever than is generally supposed, 
 and to the little apprehensiveness of disease being transmitted by 
 them may be attributed the spread of disease through families in 
 many instances. It will be seen underneath that nearly one sixth 
 of the admissions for 1836 were under ten years of age, a fact 
 which bears out what we have stated, and is also a satisfactory 
 proof of the increasing confidence which public hospitals are ac- 
 quiring from the community Of the entire treated for 
 
 the year, full two thirds were under twenty years of age. 3 We have 
 selected the statistics of these two last mentioned authors chiefly on 
 account of the large number of cases from which their conclusions 
 have been drawn — the first having treated 2257, and the second 
 3227 — in order to show the fallacy of the principles by which the 
 susceptibilities of persons to fever at the various periods of life are 
 estimated. It is obvious that the proportionate number of cases at 
 the various ages given by the above authors is only that which 
 exists in an hospital ; but it by no means follows that the same 
 ratio will be maintained among the general community. 
 
 Before any such inference could be drawn, evidence must be 
 brought forward to prove that the admissions of cases into hospitals 
 were in the same proportion as to ages as that which existed among 
 the population from whom they were sent ; for it is well known 
 that children in many towns are not so frequently sent to hospitals 
 as adults. And this circumstance may perhaps account for the 
 discrepancy which exists between the conclusions of Dr. Cowan 
 and those of Dr. Geary. This method, however, even though it 
 were ascertained that the same proportionate number of cases af- 
 fected with fever was admitted into hospitals at the various ages, 
 is very unsatisfactory, as has been pointed out by Dr. Arthur 
 Thomson ; for it does not show the number of persons living at 
 each period of life, so that an estimate may be formed of the pro- 
 portion which the number living at each term of life bears to those 
 who have been attacked. In order to supply this deficiency, the 
 author we have already quoted gives the following table : 
 
 1 Chomel, Clinique Medicale, vol. i. p. 311. 
 
 9 Cowan's Vital Statistics of Glasgow, p. 20. 
 
 3 Dublin Journal of Medical Science, vol. xii. pp. 98-9. 
 
DAVIDSON ON THE CAUSES OF FEVER. 
 
 77 
 
 C{ Table IV. — Showing the estimated number in the inhabitants at Glas- 
 gow at each age during the year 1836 ; the number attacked by fever, 
 together with the ratio attacked out of every thousand at each decennial 
 period of life. 
 
 Ages. 
 
 No. of inhabitants 
 
 No. attacked by 
 
 Ratio per 1000 at- 
 
 
 at each age. 
 
 fever. 
 
 tacked by fever. 
 
 Under 10 
 
 67.469 
 
 3811 
 
 56 
 
 10 to 20 
 
 50.009 
 
 1539 
 
 30 
 
 20 to 30 
 
 46.275 
 
 1611 
 
 34 
 
 30 to 40 
 
 32.044 
 
 911 
 
 28 
 
 40 to 50 
 
 21.758 
 
 392 
 
 17 
 
 50 to 60 
 
 14.090 
 
 294 
 
 20 
 
 "It appears from this table that the greatest susceptibility to fever 
 occurred under ten years of age, after which fever occurs most fre- 
 quently among persons between the age of twenty and thirty. The 
 number attacked after the age of thirty decreases gradually as life 
 advances." 1 
 
 This method of calculating the susceptibilities to fever is cer- 
 tainly superior to that which is deduced from the admissions into 
 hospitals ; but it is attended with the following objections, which 
 must tend to lessen the accuracy of the conclusions : 
 
 1. The number of fever cases stated in the table is not the re- 
 sult of actual observation, but is calculated from the rate of mor- 
 tality which occurred at the various terms of life in a fever hospital, 
 on the same principle that Dr. Cowan endeavoured to ascertain the 
 amount of fever in Glasgow, and which is explained at page 62 ; 
 consequently, the deduction is only an approximation to the truth. 
 
 2. The diseases of which persons die in Glasgow are reported 
 by their friends and not by their medical attendants ; and though 
 we acknowledge the great value and utility of the mortality bills, 
 even upon this imperfect plan, certainly errors respecting diseases 
 which are sometimes difficult to distinguish from others must fre- 
 quently take place. This is particularly the case with fever in 
 childhood ; which is not so easily recognised as small-pox, measles, 
 and scarlet fever, and which is frequently confounded with hydro- 
 cephalus, teething, derangements of the chylopoietic viscera, bron- 
 chitis, &c. 
 
 3. If it be admitted that typhus does not frequently attack indi- 
 viduals more than once in their lives, or even upon the principle 
 of its protecting them only for a certain number of years, it follows 
 that there must be a greater number secured by a previous attack 
 among those at the more advanced periods of life than among those 
 who are young. This point has not been prominently alluded to, 
 so far as we are aware, in any previous account of the disease; but 
 in calculating the susceptibilities of persons to fever, those who 
 
 Edinburgh Medical and Surgical Journal, July 1838, p. 92. 
 
78 DAVIDSON ON THE CAUSES OP FEVER. 
 
 have previously undergone the disease, or at least a portion of 
 them, ought to be deducted from the general population. 1 This 
 subject must, therefore, be considered as not thoroughly investi- 
 gated ; and perhaps will remain so until there be some legislative 
 enactment compelling medical practitioners to make a return of all 
 the diseases which have been treated by them throughout the year. 
 
 The observations of the British and Irish physicians do not agree 
 with those of M. Chomel, as to the maximum and minimum period 
 of life, beyond which persons are not susceptible of typhus or the 
 typhoid fever. The last mentioned author thinks it very rarely 
 occurs below ten years of age, and that perhaps no case has oc- 
 curred where the patient was beyond fifty-five years. Into the 
 Glasgow Fever Hospital there were admitted, during the year 
 1836, 2257 cases of fever'; and out of this number there were forty- 
 one under five years of age, and three between seventy and seventy- 
 five years. 2 Into the Limerick Fever Hospital, during the year 
 1836, there were admitted 3227 cases of fever, and there were 
 eighty-one below five years of age, and ten between sixty-five and 
 seventy years. 3 Dr. Craigie treated in the Edinburgh Royal In- 
 firmary seven cases of fever between sixty and seventy years, 
 among 343 admissions. 4 
 
 We have met with, in the Glasgow Fever Hospital, five cases of 
 eruptive typhus in children reported to be three years of age, from 
 the 1st May to 1st November, 1839. 
 
 Acclimatization. — M. Chomel and some other French authors 
 state that the typhoid fever attacks most readily those who have 
 been only a short time in Paris, while those who are natives of that 
 city are more frequently exempted. He mentions that among 
 ninety-two individuals, sixty-four, that is to say more than two 
 thirds, had lived in Paris less than two years, while two only were 
 natives and residents. The small number of those who were born 
 and resided in Paris is certainly remarkable ; at the same time it 
 must be kept in mind that no patient was admitted into his wards 
 below fifteen years of age. 
 
 We have constructed the following table in order to illustrate 
 this part of the subject ; and it comprehends 568 eruptive cases, 
 which were admitted into the Glasgow Fever Hospital from No- 
 vember 1st, 1838, to November 1st, 1839. It shows the number of 
 patients born in Glasgow, the number of strangers, and the dura- 
 tion of their residence in Glasgow. 
 
 s Dr. Cowan calculates that about 38,000 persons were affected withffevers 
 in Glasgow during the years 1835, 1836, 1837. 
 3 Cowan's Vital Statistics of Glasgow, p. 20. 
 
 3 Dublin Journal of Medical Science, vol. xii. p. 99. 
 
 4 Edinburgh Med. and Surg. Journal, vol. xlvi. p. 35, and vol. xlvii. p. 329. 
 
DAVIDSON ON THE CAUSES OF FEVER. 
 
 79 
 
 Strangers resident from 1 to 14 days 
 2 weeks to 1 month .... 
 
 2 to 3 months ...... 
 
 6 months to 1 year .... 
 
 10 to 20 years and upwards 
 
 Males. 
 
 Females. 
 
 Total. 
 
 77 
 
 12 
 
 7 
 
 10 
 
 10 
 
 5 
 
 5 
 
 9 
 
 29 
 
 24 
 
 13 
 
 6 
 
 12 
 
 29 
 
 36 
 
 284 
 
 99 
 4 
 6 
 
 14 
 8 
 5 
 3 
 
 12 
 26 
 17 
 10 
 11 
 4 
 32 
 33 
 
 284 
 
 176 
 16 
 13 
 24 
 18 
 10 
 8 
 21 
 55 
 41 
 23 
 17 
 16 
 61 
 69 
 
 568 
 
 It appears from this table that among 568 eruptive cases of 
 typhus, in whom this point was ascertained, 176 were natives of 
 Glasgow, and 392 were strangers : 206 of these strangers had re- 
 sided in Glasgow only from one day to two years, and 186 from 
 two to twenty years and upwards. The strangers amount to about 
 sixty-nine per cent, of the whole number of cases ; and those who 
 were affected within two years of their residence in Glasgow to 
 about fifty-two percent, of the whole number of strangers. 
 
 The following deductions may be drawn from these facts : 1. 
 That strangers are more liable to become infected with typhus 
 fever than native residents. 2. That the majority of strangers are 
 infected within a comparatively short period of their residence in 
 Glasgow. 3. That a minor proportion of the strangers, like the 
 natives of Glasgow, may escape infection for many years, and yet 
 be afterwards attacked. These results support the views which we 
 have elsewhere given of the laws of typhus. 
 
 Most of the strangers come from country districts, in which it 
 may be fairly presumed that typhus does not constantly exist, as it 
 does in large towns ; it is therefore probable that the majority of 
 them are unprotected by any previous attack : for if typhus attack 
 an individual many times during his life, why should the natives 
 of a town containing 263,000 inhabitants, who are constantly 
 within the sphere of contagion ; bear so small a proportion to the 
 
 strangers. 
 
 The facts connected with the propagation of small-pox in Glas- 
 gow are of a very similar kind ; for the majority of the un vacci- 
 nated persons who are sent to the Fever Hospital are Highlanders, 
 who have come very recently from a district where this disease is 
 not in operation, and who consequently have not previously been 
 exposed to contagion. 
 
80 DAVIDSON ON THE CAUSES OF FEVER. 
 
 Influence of trade or occupation. — Little is known accurately as 
 to the operation of the different trades, in increasing or diminishing 
 the susceptibility to fever. In manufacturing towns there are a 
 greater number of persons connected with cotton manufactures 
 affected with fever than other operatives; but this may be ex- 
 pected ; because they generally in such places constitute the most 
 numerous class among the general population. Again, in other 
 towns, labourers are the most numerous class who are affected with 
 fever. Dr. Geary, Physician to the Limerick Hospital, states that 
 "we have a tabular view before us, which shows the number in 
 families of each class of 2416 persons admitted from the city 
 parishes, and the proportion they bear to each other ; though the 
 exact relation to the general population cannot be determined, as 
 there is considerable difficulty in ascertaining the amount of each 
 trade. However, as may be expected, the labouring class being the 
 most numerous, constitute the largest number, averaging one half 
 of the entire ; and including all, we find that more than one half of 
 those treated for the year cannot be said to be of any trade, namely, 
 females and children." 1 
 
 It is an ancient opinion that tallow-chandlers, butchers, tanners, 
 and water-carriers are rarely affected with plague or fever. Dr. 
 Hancock quotes the following evidence in reference to the trades 
 that were exempted from the plague. " Volney tells us that at 
 Cairo it is observed that water-carriers, continually wet with the 
 fresh water they carry in skins upon their backs, are never subject 
 to the plague. This fact coincides with the observations in Lon- 
 don. George Baldwin, consul-general in Egypt, says that among 
 upwards of a million of inhabitants carried off by the plague in 
 Upper and Lower Egypt, during four years, he could not learn 
 that a single oilman or dealer in oil had suffered. Jackson, in his 
 reflections on the commerce of the Mediterranean, likewise informs 
 us, that in the kingdom of Tunis, there never was known an in- 
 stance of any of the coolies or porters who work in the oil stores 
 being in the least affected by the disorder ; their bodies being 
 always well smeared with oil, as well as their clothes being imbued 
 with it. We are told by Fonseca, that all the tanners at Rome 
 escaped the plague ; and Mindererus and Schenck make a similar 
 observation. Dr. Maclean refers to the exemption of tanners at 
 Cairo." 2 Dr. Tweedie notices the exemption of butchers from 
 fever, and states that though almost every description of mechanics 
 was admitted during the year into the London Fever Hospital, he 
 did not recollect of a single instance of a butcher. 3 Other phy- 
 sicians, however, have met with patients who followed this occu- 
 pation. Dr. Southwood Smith, in his table of the occupations of 
 679 patients affected with fever, enumerates three butchers, two 
 
 1 Dublin Journal of Medical Science, vol. xii. p. 103. 
 
 9 HancOck on Pestilence, p. 184. 
 
 3 Tweedie's Clinical Illustrations of Fever, p. 79. 
 
DAVIDSON ON THE CAUSES OF FEVER. 
 
 81 
 
 curriers, and two skinners. 1 Dr. Craigie, in his table of 181 cases 
 of fever treated in the Edinburgh Royal Infirmary, mentions three 
 butchers among- that number. 3 
 
 The following tables show the various trades, occupations, &c. 
 of 5S6 patients admitted into the Glasgow Fever Hospital from 
 November 1st, 1838, to November 1st, 1839. They include all the 
 eruptive cases of typhus in which the occupation, &c. were ascer- 
 tained. 
 
 Males. 
 
 Bricklayer 
 
 . 1 
 
 Fisherman 
 
 
 . . 1 
 
 Plasterer . ► . 
 
 1 
 
 Brushmaker . 
 
 . 1 
 
 French-polishe 
 
 >r . 1 
 
 Pensioner . . . 
 
 1 
 
 Brickmakers . 
 
 . 2 
 
 Glass-cutters 
 
 . 3 
 
 Printers . . . 
 
 2 
 
 Blacksmiths . 
 
 . 9 
 
 Glass-blowers 
 
 . 3 
 
 Quill-dresser . . 
 
 1 
 
 Bakers . . . 
 
 4 
 
 Gasmaker . 
 
 , . 1 
 
 Quarriers . . . 
 
 2 
 
 Currier . . 
 
 1 
 
 Gardener . 
 
 
 ♦ 1 
 
 Ropemaker . . 
 
 1 
 
 Confectioner . 
 
 . 1 
 
 Ham-curer 
 
 
 . 1 
 
 Schoolmaster . . 
 
 1 
 
 Collier . . . 
 
 . 1 
 
 Hawkers . 
 
 
 . 5 
 
 Lawyer . . . 
 
 1 
 
 Cooper . . . 
 
 . 1 
 
 Joiners . . 
 
 
 . 6 
 
 Showman . . . 
 
 1 
 
 Cabinet-makers 
 
 . 3 
 
 Labourers 
 
 
 . 76 
 
 Shoemakers . . 
 
 11 
 
 Carters . . 
 
 . 4 
 
 Last-maker 
 
 
 . . 1 
 
 Sailors .... 
 
 6 
 
 Carpenters 
 
 . 3 
 
 Maltsters 
 
 
 , . 3 
 
 Factory-workers . 
 
 22 
 
 Candle-maker 
 
 1 
 
 Masons 
 
 
 . 6 
 
 Servants . . . 
 
 4 
 
 Clerks . . . 
 
 . 2 
 
 Milk-dealei 
 
 
 . . 1 
 
 Slaters .... 
 
 3 
 
 Coffee-roaster 
 
 , 1 
 
 Optician 
 
 
 . . 1 
 
 Tailors .... 
 
 7 
 
 Dyers . . . 
 
 . 3 
 
 Nailers . 
 
 
 . . 4 
 
 Tinsmith . . . 
 
 1 
 
 Engineers . . 
 
 . 7 
 
 Policeman 
 
 
 . 1 
 
 Turner .... 
 
 1 
 
 Engineman 
 
 . 1 
 
 Porters . 
 
 
 i . 4 
 
 Tobacconist . . 
 
 1 
 
 Firemen . . 
 
 . 3 
 
 Painters 
 
 
 . 3 
 
 Wireworkers . . 
 
 2 
 
 Founders . . 
 
 4 
 
 Potters . 
 
 
 , . 3 
 
 Weavers . . . 
 
 63 
 
 
 
 Watchman 
 
 . 1 
 
 Warehouseman . 
 
 1 
 
 
 53 
 
 + 
 
 Fed 
 
 126 
 
 1ALES. 
 
 + > 
 
 L 33=3 12 tot 
 
 Weavers . . . 
 
 11 
 
 Servants . . 
 
 . 38 
 
 Hawkers . . . 
 
 6 
 
 Factory-workers 
 
 77 
 
 Fruit-dealers . 
 
 . 2 
 
 Bark-peeler . . 
 
 1 
 
 Sewers . . 
 
 25 
 
 Washerwomer 
 
 i . 2 
 
 Stocking-knitter . 
 
 1 
 
 Beggar . . . 
 
 . 1 
 
 Winders of Ys 
 
 irn 3 
 
 Straw hat-maker 
 
 1 
 
 Shearers . . 
 
 . 3 
 
 Calico-printers 
 
 3 . 2 
 
 
 
 Married . . 
 
 97 
 
 Nurses in F 
 
 .H 
 
 osp. 4 
 
 
 
 214 
 
 51 -f. 9=274 
 
 Total of Males and Females=586 
 
 Influence of Pregnancy. — Among 172 females admitted from 
 May 1st to November 1st, 1839, there were fourteen pregnant, being 
 about eight per cent, of the whole, and fully three fourths of this 
 number had abortion or premature labour during the course of the 
 disease. This appears a considerable number; but in the present 
 state of our knowledge respecting this point, we are only entitled 
 £o conclude from it that pregnancy is not an operative circumstance 
 
 1 Southwood Smith's Treatise on Fever, p. 431. 
 * Edinb. Med. and Surgical Journal, vol. xlvii. p. 286. 
 4 — b 6 dav 
 
82 DAVIDSON ON THE CAUSES OF FEVER. 
 
 in preventing the communication of typhus, and this opinion is 
 corroborated by the general experience of practitioners. Unless 
 there existed a correct enumeration of the number of individuals 
 belonging to each occupation in Glasgow, no particular deduction 
 could be drawn from these tables ; but certainly it is worthy of 
 remark that there should be no butcher, 1 no tanner, only one cur- 
 rier, only six masons, and one bricklayer, who together are a very 
 numerous class of operatives in Glasgow, while there are seventy- 
 six labourers. The latter class of operatives are generally filthy in 
 their habits and live in small ill-ventilated houses, while masons 
 are comparatively cleanly and comfortable in their circumstances. 
 
 The evidence which exists on this point, as has been already 
 stated, is still very imperfect and inconclusive; but certainly but- 
 chers and tallow-chandlers or candle-makers appear to be more 
 rarely inmates of a fever hospital than persons belonging to other 
 trades and occupations who are as numerous in the general popu- 
 lation. But there are several circumstances which influence the 
 admissions into hospitals, which ought to be taken into considera- 
 tion before any conclusion can be drawn from them. 1st. Those 
 operatives who are in better circumstances than the average class 
 of them, with the exception of servants, are more rarely sent to an 
 hospital. 2d. There may exist prejudices in a particular class of 
 operatives against hospitals. Whether any of these objections may 
 apply to the butcher or the candle-maker we are unable with cer- 
 tainty to determine, but undoubtedly the persons who followed 
 these two occupations are not below the average in point of com- 
 fort in their circumstances. 
 
 M. Parent-Duchatelet has made some very curious and import- 
 ant experiments respecting the absorption of putrid emanations by 
 various substances, which may, by analogy, be made to bear upon 
 this subject. He found that distilled water and soups possessed, in 
 a high degree, the property of impregnation with putrid effluvia ; 
 but that greasy bodies covering the surface of the liquid oppose an 
 obstacle to the passage of these emanations. The following is his 
 eighteenth experiment : " It might be useful to know if there were 
 any means capable of preventing liquids from being impregnated 
 with putrid emanations; this means chance furnished me with. 
 Having set aside a certain quantity of bouillon as an experiment, I 
 found it next day covered with a pellicle of grease, and below this 
 grease it was in a most natural state ; inferring from this experi- 
 ment I poured two or three drops of oil into each of the experi- 
 mental dishes filled with bouillon, as well as into the others filled 
 with water, and after they had remained twenty-four hours among 
 the putrid emanations I remarked that none of these liquids had 
 contracted odour, but the surface of oil gave out in all the cases a 
 
 1 One patient had been a butcher, but had worked as a labourer for six 
 months before he was affected. 
 
DAVIDSON ON THE CAUSES OF FEVER. 83 
 
 very powerful odour." 1 Solid substances were also infected with 
 the odour of putrid emanations, such as beef and wood, 3 and water, 
 completely inclosed in a piece of intestine, bladder, or strong parch- 
 ment, was even tainted with it. 3 He ascertained also that camphor, 
 valerian, and mineral tar communicated their odour to water when 
 it is exposed to the effluvia arising from these substances. 4 
 
 Although it has not been demonstrated experimentally, it seems 
 highly probable that contagious effluvia, like fetid emanations, are 
 soluble in water, from the fact that thorough ablution of the clothes 
 of persons who have laboured under fever disinfects them com- 
 pletely. Hence the advantage, as a prophylactic, of frequently 
 sponging the skin of a typhus patient with water, more especially 
 as tepid sponging is useful in the treatment of the disease. It 
 appears, also, that contagious effluvia are volatile, like the emana- 
 tions from putrid bodies, and may be separated from substances to 
 which they adhere by means of heat. The late Dr. Henry of 
 Manchester found that clothes impregnated with the miasmata of 
 scarlatina and typhus were disinfected by exposing them to a tem- 
 perature of 204° F. for one hour and three quarters, and that they 
 did not induce any of these diseases when afterwards worn by 
 healthy individuals. 5 
 
 Are we then entitled to believe that butchers, candle-makers, &c. 
 are more rarely affected with fever than other operatives? Dr. Twee- 
 die supposes the exemption of butchers to depend on their good 
 living; but it appears to us that the common theory respecting the 
 operation of oily or greasy bodies in preventing fever will also 
 explain the matter, and will apply to the butcher as well as to the 
 tallow-chandler. It has already been shown by the experiments 
 of Parent-Duchatelet, that greasy bodies attract powerfully putrid 
 emanations; and it is well known that they unite very readily with 
 odoriferous bodies of almost every kind; is it not therefore probable 
 that contagious effluvia are regulated by a similar attraction, more 
 especially when this hypothesis is coupled with the commonly 
 received opinion in eastern countries, that oil is a prophylactic to 
 contagion. If this be granted, how then does an oily or greasy 
 body protect the butcher or the candle-maker? In the exercise of 
 their various manipulations, the persons belonging to these two 
 occupations have their clothes and the uncovered parts of their 
 bodies more or less imbued with grease, an accompaniment which 
 they almost constantly carry about with them. The contagious 
 effluvia may, therefore, in place of being absorbed by the skin, 
 combine permanently with the fatty body, and in this be fixed and 
 rendered harmless. 
 
 We only bring forward this as an hypothesis capable of account- 
 ing for the generally received opinion respecting the protecting 
 
 1 Annales d'Hygiene Publique, torn. v. p. 39. 
 
 * Ibid. p. 44. 3 Ibid. p. 39. « Ibid. p. 38. 
 
 6 Philosophical Magazine, Nov. 1831. 
 
84 DAVIDSON ON THE CAUSES OP FEVER. 
 
 property of oil ; but certainly if there be prophylactic powers in it 
 or in any other substance, it is well worthy of being investigated 
 experimentally. 
 
 ON THE IDENTITY OF TYPHUS AND THE TYPHOID FEVER. 
 
 As we have made several quotations from M. Chomel, as well as 
 from M. Louis, who seem to think that the typhoid fever of France 
 is a different disease from the ordinary British typhus, it may be 
 necessary to show, although it may appear foreign to this essay, 
 upon what grounds we consider them identical. The evidence by 
 which the identity of typhus and the typhoid fever may be esta- 
 blished, consists of two kinds, namely, the symptoms during life, 
 and the morbid appearances after death ; and in order that the 
 subject may not be entrammeled with unnecessary detail, those 
 symptoms and lesions only which in the aggregate are reckoned 
 diagnostic of the disease shall be described. M. Chomel describes 
 the disease under three septennary periods, each being character- 
 ised by peculiar symptoms. First period is characterised by feeble- 
 ness, stupor, sleeplessness, mutterings, meteorismus, diarrhoea, 
 sensibility of the abdomen, and a sense of fluid gurgling in the 
 lower half of the belly, epistaxis, the typhoid eruption, and frequent 
 pulse. Second period is characterised by the eruption which M. 
 Chomel admits to be similar to that described by Hildenbrand, as 
 observed in the typhus castre?isis, sudamina, ulcerations and 
 sloughs on various parts, chops and ulcers in the tongue, increased 
 stupor, unconsciousness, dorsal decubitus, difficulty of deglutition, 
 involuntary evacuations, retention of urine, subsultus tendinum, 
 picking of the bedclothes, general and permanent rigidity of the 
 members, deafness, coma, small weak tremulous pulse, or throbbing 
 and intermittent, and varying in frequency from 80 or 90 beats to 
 120 in a minute, but which sometimes sinks to 40 or 50, a fuli- 
 ginous coating of the tongue, teeth, gums and lips, diarrhoea, intes- 
 tinal hemorrhages, increased meteorismus, respiration more con- 
 strained, fetid exhalations from the skin and breath. Third period. 
 It is generally during this stage that the febrile disorder subsides, 
 whether the patient recovers or dies. When the termination is 
 going to be favourable the patient becomes more sensible, is more 
 disposed to sleep, the mouth and tongue become more moist, the 
 fecal discharges more natural, and the pulse becomes less frequent. 
 On the other hand, when the termination is going to be unfavour- 
 able, the stupor increases, there is an alteration in the features, 
 stertorous breathing, feebleness of pulse, a drier skin, or cold and 
 covered with clammy sweat, general emaciation, hollow eyes, 
 tremulous speech, indistinct and murmuring answers to questions. 
 
DAVIDSON ON THE CAUSES OF FEVER. 85 
 
 extreme feebleness, coma, and death. Sometimes death is accele- 
 rated by the occurrence of tetanic or epileptic paroxysms, and 
 intestinal perforations and erysipelas are mentioned as occurring 
 during convalescence. Any practitioner who has paid close atten- 
 tion to the symptoms of British typhus will readily discover their 
 identity with those so well described by M. Chomel, as indicating 
 the typhoid fever. There are, however, too or three symptoms 
 which he places more dependence upon as characteristics of the 
 disease than what is generally done in Britain, which it is neces- 
 sary to notice more particularly. He represents diarrhoea as a 
 very common symptom in the majority of cases, there being from 
 four to eight alvine evacuations daily. Now this symptom by no 
 means occurs frequently in Britain, but this discrepancy may, to a 
 certain extent, be explained, for the French physicians seldom 
 exhibit purgatives in case of aggravating the g astro-enter ite ; 
 hence the solid excrementitious matter which naturally accumu- 
 lates in the torpid bowels of a typhoid patient will produce a mor- 
 bid secretion from their excited surfaces, and being tinged with 
 feculent matter may represent a fecal diarrhoea. This view is 
 supported by the admission of M. Chomel himself. He states that 
 " in some cases, at the time when the first improvement in the 
 symptoms occurs, the alvine evacuations consist of firm, figured 
 motions, to the great astonishment of the attendants, who with 
 difficulty understand how such a change could be effected in so 
 short a time. It is probable that these matters had remained dur- 
 ing the whole period of the disease in some of the cells of the colon, 
 and had not prevented the passage of liquid motions. There are 
 discharged sometimes in these cases prodigious quantities of black 
 dry matters." 1 From M. Chomel's account it would appear that 
 meteorism or tympanitic swelling of the belly is more frequent in 
 France than in Britain, for it has never been considered in this 
 country as peculiarly characteristic of typhus. This discrepancy 
 may, however, be reconciled, for according to this author the 
 meteorism is only to be discovered in the early stages by percus- 
 sion, while in the latter stages it is discoverable from the convex 
 form of the belly. British practitioners apply the term tympanitis 
 only to prominent distention of the belly by flatus, while those in 
 France apply it not only to this but to minor enlargements not dis- 
 coverable by the eye. Epistaxis is another symptom which M. 
 Chomel considers frequent, and of great value as a diagnostic of 
 typhus, especially if it occur during the first days of the disease. 
 These hemorrhages are not profuse, but are most generally only a 
 few drops, either from the anterior part of the nasal cavities or 
 from the posterior by the throat, in the form of mucous masses, 
 streaked and mixed with blood. Bleeding from the nose or mouth 
 ?.s certainly not so frequent in Britain as to constitute a diagnostic 
 
 1 Chomel, Le£ons de Clinique Medicale, torn. i. p. 42. 
 
86 DAVIDSON ON THE CAUSES OF FEVER. 
 
 symptom of typhus, although it does occasionally occur ; but it is 
 generally hemorrhage to a considerable extent which has been 
 noticed by authors in this country, and we do not doubt that the 
 smaller discharges of blood or bloody mucosities have occasionally 
 been overlooked or not attended to, as unimportant. M. Chomel, 
 although he does not appear to be perfectly convinced that typhus 
 and typhoid fever are the same disease, is strongly inclined to this 
 opinion from the similarity of their symptoms. He says that 
 " another point which is still in favour of the opinion of contagion 
 is the analogy which exists between the typhoid affection and 
 typhus of camps, the contagious character of which is contested by 
 no person. If we compare these two diseases, and from our recol- 
 lections and from the description which has been given by Hilden- 
 brand, and which it was in our power during 1814 to verify the 
 accuracy, we shall find the same symptoms in the two affections, 
 both of them commence by headach, with most subjects prostration 
 and stupor appear at the beginning, and not solely, as in other 
 affections, after the malady has endured a long time, and has very 
 greatly debilitated the organism. The other symptoms, such as the 
 meteorism, the diarrhoea, the notable weakness of the senses, the 
 tendency to ulcerations and hemorrhages, are common to the two 
 diseases. The progress is the same in the two diseases, inflamma- 
 tory symptoms predominate at first and are afterwards followed by 
 nervous or adynamic phenomena. One of the few differences 
 which we have observed between these two affections consists in 
 the duration, which is more prolonged in the typhoid affection 
 than in typhus. This last ceases generally about the fourteenth 
 day ; whilst it is rare that the first terminates before the twentieth 
 day, Another difference consists in the frequency with which true 
 petechias or purple spots are observed in typhus, which are com- 
 paratively rare in the typhoid malady. With regard to the cutane- 
 ous exantheme or typhoid eruption, it presents the same characters 
 in the two affections ; the only differences are in the number of 
 spots and in the period of their appearance. In place of being con- 
 fined, as they are most frequently in the typhoid fever, to the belly 
 and chest, the lenticular spots in typhus cover and in greater num- 
 bers almost the whole surface of the body. In this last the eruption 
 is developed generally about the fourth day of the disease ; in the 
 typhoid fever it appears only about the eighth day, and sometimes 
 
 much later The only difference which Hildenbrand 
 
 and Pringle admit between typhus and the most of other fevers 
 which we have referred to the typhoid malady, is that the severity 
 of the disease is greater in typhus, its progress more rapid, the 
 adynamic phenomena more decided, and the eruption more gene- 
 ral ; but. these differences are not sufficient to make us reject the 
 identity of the malady, for they may depend upon circumstances 
 more or less troublesome, during which it is propagated. These 
 
DAVIDSON ON THE CAUSES OF FEVER. 87 
 
 differences may rather indicate degrees of intensity than that they 
 are maladies entirely distinct." 1 
 
 These distinctions between typhus and typhoid fever, as stated 
 by M. Chomel, must appear to every one sufficiently acquainted 
 with the typhus of Britain as very unimportant, for in young per- 
 sons the eruption is frequently observed upon the extremities as well 
 as upon the breast and belly, and even in the same family, when 
 the disease ought to be acknowledged as identical, the number of 
 spots observed on each member of it often varies exceedingly. It is 
 also a well-known fact that complete convalescence from typhus fever 
 rarely takes place on the fourteenth day except in young persons ; 
 while among those more advanced twenty or a greater number of 
 days may elapse before this occurs. 
 
 In order to show still further the identity of the symptoms of 
 typhus with the typhoid fever, we shall quote the observations of a 
 very accurate and experienced physician, Dr. Lombard, of Geneva. 
 He states that " with this experience and having witnessed numer- 
 ous dissections of subjects dead of typhus fever, and having found 
 in every one of them at Paris and at Geneva the morbid state of 
 the intestinal canal which the French pathologists consider as 
 essential: under these circumstances, when I arrived in Great 
 Britain and had an opportunity of seeing the fever cases here, and 
 when I found that they presented a very great similarity, if not an 
 identity, of symptoms with those I had been for years in the habit 
 of observing, it is not to be wondered at, I say, that I should have 
 expected to find exactly the same post-mortem appearances. I 
 mentioned this subject to my friends at Glasgow, and they allowed 
 me to dissect the body of a person in whom I said no doubt could 
 exist as to the presence of follicular disease; judge then, how great 
 was my astonishment at not being able to detect a single trace of 
 this morbid change in any part of the intestinal canal, and at find- 
 ing no marks of disease save some redness and softness of the 
 mucous membrane of the stomach, which may have been produced 
 by inflammation, but more probably was owing to muscular con- 
 gestion, occurring during the last stage of the disease, or even dur- 
 ing the agony that precedes death." 2 
 
 Dr. Lombard, however, was not convinced by this inspection ; 
 and on his arrival at Dublin he examined the bodies of two patients 
 who had died of typhus at different hospitals, and with the same 
 results. It thus appears that the symptoms of typhus and the 
 typhoid fever are nearly the same, and that they cannot be distin- 
 guished from one another ; so that upon this ground their separa- 
 tion cannot be maintained. But those who support the difference 
 of the two affections rest their proof chiefly upon the pathological 
 lesions which are found in the intestines. 
 
 M. Louis characterises the typhoid fever under the following 
 
 1 Chomel, Leijons de Clinique Medicale, torn. i. p. 335. 
 
 2 Dublin Journal of Medical Science, vol. x. p. 18. 
 
88 DAVIDSON ON THE CAUSES OP FEVER. 
 
 description: " An acute malady accompanied with a febrile move- 
 ment more or less intense, variable in its duration, proper to young 
 persons, chiefly to those who are placed within a short time in cir- 
 cumstances new to them, the cause of which is unknown, com- 
 mencing by a violent shivering, anorexia, thirst, and in the great 
 majority of cases by colics and diarrhoea, very soon accompanied 
 by feebleness which is small in proportion to the other symptoms, 
 then more or less quickly somnolence, stupor, delirium, meteoris- 
 mus, sudamina, lenticular rose-coloured spots, ulcers on the sacrum, 
 ulcerations more or less deep of the skin, in the parts occupied by 
 blisters, deafness, various spasmodic movements, or permanent con- 
 traction of the limbs ; symptoms some of which disappear after a 
 certain time, others increase for the most part in a progressive 
 manner, when the patients die, or diminish more or less rapidly, at 
 length to disappear altogether if the affection has a happy termina- 
 tion ; the anatomical characters of which consists in a special 
 
 alteration of the elliptic plates of the ilium. 1 Of all 
 
 these lesions one only is constant, being found in all the subjects: 
 I speak of the alteration of the elliptic plates of the small intestines, 
 to which may be added the alteration of the mesenteric glands; I 
 have regarded it as inseparable from the existence of the affection 
 under review in forming the anatomical character. And ^is it was 
 more or less great with some subjects who died on the eighth day 
 of the disease, as with the greatest number the first symptoms indi- 
 cated a lesion of the intestinal canal, as the alterations of the small 
 intestines was greater than those of the colon, which was sound in 
 a sufficiently large number of cases, I am warranted to conclude 
 that the alteration of the elliptical plates commenced at the begin- 
 ning of the disease." 2 M. Chomel, although he appears strongly 
 inclined to support the doctrines of M. Louis and the other French 
 pathologists, makes the following candid avowal of his opinion 
 deduced from a rigid examination of all the pathological facts con- 
 nected with the typhoid fever: " If, to this consideration furnished 
 by analogy, we join these two other circumstances already esta- 
 blished : 1st, that there is no constant proportion between the 
 severity of the symptoms and that of the lesions of the follicles ; 
 2d, that the lesion has been completely absent in subjects who had 
 offered during life all the symptoms of typhoid affection — it will 
 become still more evident that the typhoid malady does not consist 
 essentially of inflammation of the follicles ; that this inflammation 
 is only one of the phenomena of the disease, that it belongs, like 
 most of the disseminated inflammations, to secondary inflamma- 
 tions ; that it may be compared as to its pathogenic power not even 
 to the pustules in variola, for in this there is always a proportion 
 between the number of the pustules and the severity of the malady, 
 but rather to the bubo in the pestilence of the East." 3 
 
 ' Louis de Gastro-Enterite, torn. ii. p. 317. 2 Ibid. torn. i. p. 449. 
 3 Chomel, Leijons de Clinique Medicale, torn. i. p. 536. 
 
DAVIDSON ON THE CAUSES OF FEVER. 89 
 
 M. de Claubry, in his prize essay read before the Royal Academy 
 of Medicine, has adduced very copious evidence to prove the iden- 
 tity of typhus and the typhoid fever. He controverts the opinions 
 of M. Louis respecting the ages that are exempt from the typhoid 
 fever, and states that " it is not rare to see the disease in the Pari- 
 sian hospitals at the age of four, six, eight, and ten years ; and that 
 M. Andral has witnessed it after seventy years." 1 He adduces 
 Fauvages, Reveille, Parise, Thruvenel, Ducastaing and Pellerin, 
 to prove that ulcerations having elevated borders and exposing the 
 peritoneal coat were found near the extremity of the small intestine 
 in typhus. 2 The same author also shows that the typhoid fever 
 spreads by contagion in the same way and under the same circum- 
 stances as typhus. 3 Dr. Lombard, who contends for the distinction 
 of the two diseases, adduces similar evidence to prove that typhoid 
 fever is possessed of contagious qualities. 4 
 
 We think it unnecessary to adduce evidence to prove that the 
 follicular disease of the intestines is greatly less frequent in British 
 typhus than in the continental typhoid fever ; for the pathological 
 investigations which have been made in England, Scotland, and 
 Ireland, regarding this point, are now numerous and well known. 
 Indeed in this country, in place of finding in almost every subject 
 who died of typhus fever disease in the agminated or solitary 
 glands, the minority has been the proportion found in many hospi- 
 tals, and the affection of the spleen and brain more frequent than 
 that of the intestines. If then there be no specific difference be- 
 tween typhus and typhoid fever ; why are the pathological lesions 
 of the intestines so much more common and intense in France than 
 in Britain 7 It is perhaps not possible to give a satisfactory answer 
 to this question, unless a difference of climate, diet, habits, &c. be 
 allowed a certain influence. Dr. Lombard, in his first letter to Dr. 
 Graves, seemed to have formed a very correct opinion respecting 
 the nature of typhus, although he afterwards thought proper to 
 change his views. In his first letter he says that "all these con- 
 siderations, my dear friend, seem inevitably to lead to the conclu- 
 sion that typhus fever is more a general disease affecting the whole 
 constitution than a malady depending on a local inflammation or 
 any local change of structure. May we not infer, also, that various 
 causes serve to impress upon this general disease a tendency to 
 associate itself with and produce various local ailments; among 
 these causes, the most influential probably are, climate, seasons, 
 the race of mankind, diet, and various circumstances which act 
 powerfully both on the mind and body, and which when concen- 
 trated at any one point of time have given rise to those various 
 epidemics of typhus that have so frequently devastated the different 
 
 1 Mernoires de l'Academie de Medecine, vol. vii. p. 190. 
 
 2 Ibid. p. 80. 
 
 8 Ibid. p. 120. 
 
 4 Lombard's Clinical Remarks on Bilious and Typhoid Fevers, p. 17, 
 
90 DAVIDSON ON THE CAUSES OF FEVER. 
 
 countries of Europe." 1 The same author, however, in his second 
 letter to Dr. Graves, assumes his old hypothesis that the two fevers 
 are different, and goes even a step further, for he maintains that 
 both kinds are to be met with in the British and Irish hospitals. 
 His views seem to be included in the following" quotation from his 
 letter : " But the Irish contagious fever is not the only source of 
 typhoid diseases in Great Britain ; the sporadic continued fever, 
 observed in all parts of Europe, is also to be found in the different 
 towns of the British empire. This fever, characterised by the fol- 
 licular intestinal eruption and by consequent ulcerations, is to be 
 seen in the different places above mentioned ; in Glasgow it forms 
 one third of the total number of cases ; 2 in Dublin the proportion 
 is much less ; in London it is one fourth, and varies in the different 
 seasons, because the continued sporadic fever is much under the 
 influence of the temperature, being more frequent in autumn than 
 in spring and winter ; a proof that the proportion of this sporadic 
 fever is the cause of the greater proportion of ulceration cases found 
 at times in the British hospitals, as already mentioned. Having 
 stated my opinion on your British continued fever, I resume it in 
 the following theoretical view : You have two different fevers, one 
 highly contagious, which I may call the Irish typhus, and in which 
 the cephalic symptoms predominate to the exclusion of abdominal 
 alterations ; the other which is sporadic and most likely not so in- 
 fectious, and in which the abdominal symptoms are more predomi- 
 nant, so much so that the follicular disease and consequent ulcera- 
 tions are always to be found." 3 Dr. Gerhard, of Philadelphia, is 
 another author who endeavours to show that there is a specific dif- 
 ference between typhus and typhoid fever, and that both are to be 
 met with in Philadelphia. He makes the following observations 
 respecting the post mortem appearances which were observed in 
 the American typhus: "In this large number of autopsies, amount- 
 ing to about fifty, there was but in one case, and that doubtful in 
 its diagnosis, the slightest deviation from the natural appearance of 
 the glands of Peyer. In the case alluded to, in which there had 
 been some diarrhoea, the agglomerated glands of the small intes- 
 tines were reddened and a little thickened, but there was no ulcer- 
 ation and no thickening or deposit of yellow puriform matter in 
 the submucous tissues. The disease of the glands resembled that 
 sometimes met with in smallpox, scarlet fever, or measles, rather 
 than the specific lesion of dothonenteritis." 4 
 
 1 Dublin Journal of Medical Science, vol. x. p. 23. 
 
 2 In some places in Scotland ulceration of the intestines seems to be very 
 frequent. Dr. John Reid states that Dr. Goodsir, of Anstruther, examined 
 ten bodies, and in every one the elliptical patches of Peyer and the solitary 
 glands at the lower part of the ilium were elevated and ulcerated, and in 
 four, perforation of the intestines had taken place. Edinb. Medical and 
 Surgical Journal. Oct. 1839, p. 459. 
 
 8 Dublin Journal of Medical Science, vol. x. p. 104. 
 
 4 American Journal of Medical Sciences. February, 1837. 
 
DAVIDSON ON THE GAUSES OF FEVER. 91 
 
 Dr. Gerhard's account of the epidemic typhus in Philadelphia is 
 written with great accuracy, and his post mortem inspections seem 
 to have been conducted with much care and ability; but his re- 
 sults are certainly not what might be expected from a disease of the 
 same nature as British typhus, which he describes it to be. For 
 though we by no means believe that the lesion of Peyer's glands is 
 a necessary concomitant of typhus, we are certainly supported by 
 British observations when we state that there never were fifty con- 
 secutive inspections of typhus subjects made in this country with- 
 out finding one decided instance of disease in the intestinal follicles. 
 
 It is quite evident that Drs. Lombard and Gerhard lay almost 
 the whole weight of the diagnosis of typhus from the typhoid fever, 
 upon the lesions of the intestinal follicles observed in the latter dis- 
 ease ; for the almost identity of their symptoms during life are ad- 
 mitted ; and is there any British practitioner that could distinguish 
 those cases of eruptive typhus that had diseased follicles from "those 
 that had not? Again, it may be asked, what is the peculiar cha- 
 racter of the diseased follicles, which constitutes the distinction be- 
 tween typhus and typhoid fever? In subjects dead of typhus fever 
 which we have examined, the follicles are generally found with 
 their margins only distinctly defined, but with little elevation or 
 thickening of the subjacent textures, but such as to give a compara- 
 tive opacity to the patch ; when viewed with a magnifier, their 
 surface presents irregular mammillated projections, bounded by 
 corresponding depressions ; sometimes there is only one patch, 
 more frequently two or three, or a large irregular coalescence of 
 patches at the ileo-csecal valve ; deep ulceration is not very com- 
 mon except in protracted cases ; and occasionally there is the ap- 
 pearance of superficial ulceration. Now, if the anatomical and 
 distinctive character of the typhoid fever be a morbid alteration of 
 Peyer's glands, one single diseased patch, characterised by its de- 
 fined margin, greater or less elevation and opacity, ought to con- 
 stitute the disease as definitely as if there were twenty ; just as 
 small-pox is as essentially distinguished by twenty or thirty pus- 
 tules as by several hundreds. If this be denied, where lies the line 
 of separation ? 
 
 Does it consist in a certain elevation of the follicles capable of 
 admeasurement, in the deposition of a yellowish white or puriform 
 matter in their subjacent textures, or in a certain amount of ulcer- 
 ation ? But it may be argued that there are two species of fever in 
 Britain, the one characterised by a peculiar disease of the intestinal 
 follicles, and the other unaccompanied by any such lesion j and 
 that some slight disease, characterised by a slight elevation and 
 configuration of the patches, does sometimes take place in the latter, 
 such as occurs in scarlet fever, small-pox, &c. ; but that this lesion 
 is totally different from that described by Louis and Chomel as 
 characteristic of the typhoid fever. Now, we are ready to admit, 
 at least as far as our experience goes, that the elevation and texture 
 
92 DAVIDSON ON THE CAUSES OF FEVER. 
 
 of the follicles are not in many cases precisely similar to those 
 which are stated to be characteristic of the typhoid fever ; but cer- 
 tainly they are even in this state morbidly affected. 
 
 The following table shows the lesions that appeared on the in- 
 spection of sixty-three eruptive cases, that were admitted into the 
 Glasgow Fever Hospital from 1st May to 1st November, 1839, and 
 it includes both male and female patients in nearly equal propor- 
 tions : 
 
 Abnormal serum in brain 34 
 
 Bronchia red . 25 
 
 Spleen rather large and soft 14 
 
 Spleen large and pulpy . . 30 
 
 Peyer's glands enlarged 1 to 3 12 
 
 Peyer's glands enlarged 3 to 6 14 
 
 Peyer's glands enlarged 6 and upwards . . . .22 
 
 Solitary glands enlarged 14 
 
 No intestinal glands enlarged 12 
 
 Ulceration of intestines 13 
 
 The mesenteric glands were almost uniformly enlarged when 
 ulceration of the intestines was present, but very rarely in other 
 cases. 
 
 Now it may be contended that this simple enlargement or figura- 
 tion of the intestinal follicles is a different affection from that which 
 occurs in the continental typhoid fever, and hence ought to have 
 a different classification. Such an assumption would lead to an 
 endless and very unphilosophical division, and obviously to the 
 formation of three species of typhus, out of the various complica- 
 tions or appearances which are observed in the intestines; namely, 
 1st, typhus without any intestinal affection whatever ; 2d, typhus 
 with simple enlargement of Peyer's glands ; 3d, typhoid fever com- 
 plicated with the follicular affection described by M. Louis; for if 
 one author distinguish a species by a peculiar morbid appearance 
 of the intestinal follicles, another has the same right to form a 
 second, if the affection of these glands, in a certain number of other 
 cases, be denied a pathological similarity to the first ; whilst the 
 morbid affections of the spleen, the lungs, the brain, &c. might all 
 be brought forward to increase the subdivision still farther. The 
 strength of our argument, however, that typhus and typhoid fever 
 are the same diseases modified by place, season, epidemic influence, 
 and perhaps by circumstances not yet ascertained, lies in the fact, 
 that it has been admitted that cases of the latter disease, although 
 rare, have occurred without any morbid appearance being disco- 
 vered in the intestinal follicles ; proving that this morbid condition 
 of these glands is not a necessary anatomical character of the dis- 
 ease, such as hepatization or suppuration is of pneumonia, or serum 
 of hydrocephalus. It has also been admitted that the intensity of 
 the symptoms is not proportional to the lesions which ought to 
 occur if the latter were the cause of the former ; and it would be 
 contrary to all experience to attribute the formidable symptoms of 
 
DAVIDSON ON THE CAUSES OF FEVER. 93 
 
 typhus or the typhoid fever to the lesion of one or two intestinal 
 follicles, even though affected in the form described by the French 
 writers. Would it not, therefore, be refining our classification of 
 diseases beyond all precedent, to separate typhus and typhoid fever 
 into two species, where it has been shown that the symptoms in 
 both are the same, or very nearly so, that they have nearly the 
 same laws, as far as these have been ascertained ; that the severity 
 of the symptoms in both is not in proportion to the lesions of the 
 intestinal follicles ; and that the other complications of both are 
 similar, although various in the same places at different periods, 
 while the only characteristic in dispute has been acknowledged not 
 a constant and therefore not a necessary element for the existence 
 of the disease. 
 
II. 
 
 AN INQUIRY 
 
 INTO THE SOURCES AND MODE OF ACTION OF THE 
 
 POISON OF FEVER. 
 
 BY ALFRED HUDSON, M. B. T. C D. 
 
 PHYSICIAN TO THE NAVAN FEVER HOSPITAL. 
 
 Much as has been written upon the history of fever, it cannot by 
 any means be considered as an exhausted subject. If indeed we 
 were to test our knowledge of its sources by the universality of 
 their admission, and consider the general agreement of all obser- 
 vers as to their laws as the true proof of these being fully ascer- 
 tained — a criterion which is applicable to medicine as to the other 
 sciences of observation — we should see reason to conclude that 
 in reality our knowledge of the causes of fever and their modes of 
 action upon the living body is of very small account, and by no 
 means of the most accurate description ; for though, in this country 
 at least, the doctrines of localisation of fever are not advocated, nor 
 fever considered the effect of inflammation of any particular organ 
 or organs, we find in the most recent writers, equally as in the 
 ancient, the widest differences of opinion as to the phenomena 
 which constitute the origin or nature of this essential disease. 
 
 An analysis of the mass of conflicting statements upon this sub- 
 ject may perhaps be useful, if only as a preliminary step to other 
 inquiries, by showing how much of what has been put forward as 
 evidence is really founded on observation, and how much is on the 
 contrary mere matter of opinion and not of fact. Such an exami- 
 nation of what has been advanced upon the disputed question, it is 
 proposed to attempt in the following inquiry. 
 
 We regard the essential disease termed fever as the effect of the 
 action on the living body of a morbid poison — in other words of — 
 
 " One of that peculiar class of substances which are generated 
 during certain processes of decomposition, and which act upon the 
 animal economy as deadly poisons ; not on account of their power 
 
96 HUDSON ON THE CAUSES OF FEVER. 
 
 of entering into combination with it, or by reason of their contain- 
 ing a poisonous material, but solely by virtue of their particular 
 condition." 1 
 
 The mode of operation of this poison upon the body is a fertile 
 theme for disputation between the humoralists and solidists of this 
 as of preceding ages, and whence it is derived and where generated 
 — whether in the body or out of the body — the contagionists and 
 non-contagionists are as much disagreed about as ever. 
 
 The humoralist holds that the very definition of a morbid poi- 
 son, if correctly given by the distinguished author from whom we 
 have adopted it, would point to the blood as the subject of its ope- 
 rations. Since, assuming that the essence of such poison is that its 
 elements are in a state of decomposition or transposition — and its 
 action to communicate that peculiar- transposition to the consti- 
 tuents of the body with which it may be brought into contact, he 
 finds in the blood a substance the most susceptible of any part of 
 the organism of the action of exterior influences, and whose con- 
 stituents are the most prone of any to form new combinations. The 
 humoralist also points to the analogy of other morbid poisons, 
 which produce their specific effects upon their direct introduction 
 into the blood. He points to the latent period common to both ; 
 and, if he be a contagionist (as he must be,) he sees in the forma- 
 tion of the poison by the blood the consequence of the introduction 
 of organic matter in a state of progressive transposition or decom- 
 position (such as is the contagious miasm) into a mixed fluid in 
 which its constituents are contained, and. the reproduction in that 
 fluid of the exciting body, exactly as yeast is reproduced when 
 added to a mixed fluid in which the gluten from which it originated 
 is contained. On the other hand, the solidist considers that the 
 nervous system is so much engaged in fever, that the poison must 
 be there, or, the phenomena of the latent period are attributable to 
 the nervous system, or, dating this commencement of fever from 
 the nervous shock, sometimes attendant on exposure, and assuming 
 that the poison is received into the organism then and there, he 
 sees an analogy between the action of the poison and certain nar- 
 cotic substances which he assumes act on the nervous system 
 without entering the circulation ; — and therefore — fever so acts — 
 or — lastly, the source of the poison not being apparent, and the 
 shock preceding the fever, he finds that he can produce contagious 
 fever by a moral impression on the nervous system without the 
 action of a poison at all ! These are some of the different opinions 
 maintained by recent and able writers on the nature of fever, and 
 which we shall have to glance at when considering the mode of 
 action of the sources of the disease. As to these sources, our latest 
 writers are so disagreed as to make an analysis of their opinions 
 and evidence no easy matter. If we placed them in juxtaposition 
 
 1 Liebig's Organic Chemistry. 
 
HUDSON ON THE CAUSES OF FEVER. 97 
 
 according to the doctrines propounded and denied, onr index would 
 run thus — 
 
 Fever contagious — not contagious. 
 
 Arises from putrefying animal matter — denied. 
 
 Arises from putrefying vegetable matter — denied. 
 
 Infection a direct emanation from the patient — denied. 
 
 Infection capable of being generated de novo — denied. 
 
 Atmosphere of patient infectious — denied. 
 
 Contact of ditto infectious — denied. 
 
 Fomites infectious — denied. 
 
 Fever originating in miasm contagious — denied. 
 
 Identity of foregoing with typhus asserted and denied. 
 
 These conflicting opinions will come under review successively 
 in the course of an examination into the following questions. 
 
 1. The existence of a special animal poison arising from infec- 
 tion, and producing a specific disease — typhus. 
 
 2. The generation during the decomposition of organic sub- 
 stances of a poison capable of producing fever when applied to the 
 living body. 
 
 3. The power of this paludal fever to communicate itself from 
 one individual to another. Does it possess the power of infection 
 per se 1 in other words, are typhus and typhoid fevers identical? 
 or, does it acquire it by the aid of adventitious circumstances, and 
 so become communicable by conversion into or superaddition of 
 typhus ? 
 
 4. Arising out of the preceding is the inquiry — what are the ad- 
 ventitious aids to the diffusion of each kind of fever ? the laws 
 which regulate their epidemics, and the sanatory measures best 
 calculated to neutralise their operation. 
 
 CHAPTER I. 
 
 Of the Infectious A.nimal Poison generated in the living Human Body, and capable of 
 producing Fever when applied to Healthy Bodies. 
 
 Sect. 1. — Proof of its tangible existence. — It might have been 
 supposed that the accumulated evidence of infection presented in 
 the histories of the typhus of Great Britain, would satisfy the most 
 incredulous ; but it is not so, and a recent author has denied the 
 existence of such a cause of fever as atmospheric contagion 1 — in 
 other words, of "an atmosphere holding in solution a specific con- 
 tagious poison." Because — " it has never been unequivocally mani- 
 fested to any of the external senses ; it has never been seen com- 
 bined with the atmosphere, or precipitated from it, or abstracted 
 therefrom to solid bodies." 
 
 It has been urged in reply, that this is equally the case with 
 miasm and vitiated air of all kinds, which last, this author himself 
 
 1 Dr. Scott Allison — Essay on Contagion. 
 4— c 2 hudson 
 
98 HUDSON ON THE POISON OF FEVER. 
 
 has endeavoured to prove, is the source of contagious fevers. But 
 this answer is not correct, the fact being, that organic matter in a 
 state of decomposition, or progressive transformation, is present in 
 both. We shall hereafter adduce evidence of this fact with regard 
 to miasm. As to its presence in aerial contagion Liebig states that 
 — " all the observations hitherto made upon gaseous contagious 
 matters prove that they also are substances in a state of decompo- 
 sition. When vessels filled with ice are placed in air impregnated 
 with gaseous contagious matter, their outer surfaces become covered 
 with water containing a certain quantity of this matter in solution. 
 This water soon becomes turbid, and in common language, putre- 
 fies ; or, to describe the change more correctly, the state of decom- 
 position of the dissolved contagious matter is completed in the 
 water. The odour of gaseous contagious matters," says the same 
 author, " is generally accompanied by ammonia, which may be 
 considered in many cases as the means through which the conta- 
 gious matter receives a gaseous form Ammonia is very 
 
 generally produced in cases of disease ; it is always emitted in 
 those in which contagion is generated, and is an invariable product 
 of the decomposition of animal matter. The presence of ammonia 
 in the air of chambers, in which diseased patients lie, particularly 
 of those afflicted with a contagious disease, maybe readily detected; 
 for the moisture condensed by the ice in the manner just described, 
 produces a white precipitate in a solution of corrosive sublimate, 
 
 just as a solution of ammonia does By evaporating acids in 
 
 air containing gaseous contagions, the ammonia is neutralised, and 
 we thus prevent farther decomposition and destroy the power of 
 the contagion, that is its state of chemical change." 
 
 " To this decisive proof of its presence may be added the fact of 
 its being frequently recognised by one of the senses, that of smell, 
 in those cases, in which it has proved active as a poison. For in- 
 stance — a gentleman in this neighbourhood, not long since, passed 
 through a severe and lengthened typhus fever. About the tenth 
 day of convalescence, while walking across the room, leaning upon 
 the arm of his son, the latter was struck by the odour from his 
 father's body ; he immediately became sick at stomach, and on the 
 next day had rigour followed by fever of the same type and dura- 
 tion (21 days) as his father's." 
 
 Dr. Montgomery's 1 attack of fever, related by himself, gives simi- 
 lar proof that the aerial contagion may be occasionally recognised 
 by this sense. 
 
 "On the 10th of August, I visited a patient in fever, and hearing 
 from the nurse that there were spots on the patient's skin, I stooped 
 very close to her to satisfy myself, and while so doing, I was sensi- 
 ble of a very disagreeable odour from the skin. At the moment, it 
 made a considerable impression on the sense of smell, being almost 
 as pungent as the odour from an ammoniacal salt. The smell con 
 tinued in my mind all day, &c." 
 
 1 In Marsh's Essay on the Origin of Fever. 
 
HUDSON ON THE POISON OF FEVER. 99 
 
 It is true a sceptical reasoner might argue for the possible exist- 
 ence in such cases of an unhealthy locality, impure air, &c. ; but 
 much of the evidence of contagion which we possess, is free from 
 any such objection. 
 
 Sect. II. — The Testimony in proof of the Poioer of this Poi- 
 son to cause Fever — or, as it may be expressed, the proof that the 
 disease has arisen from exposure to the emanations from the bodies 
 of those similarly affected, requires to be of a very exact kind, since 
 the opponents of the doctrine of infection, who, like the writer 
 above quoted, affirm, that "those who have communication with 
 the sick do not suffer in a greater proportion than those who keep 
 apart," explain the many instances in contradiction of this asser- 
 tion which occur among the medical attendants, nurses, and rela- 
 tives of the sick, by attributing them to the "locality" and to 
 " impure air," and add, that "it is however almost entirely on such 
 exceptions as these that the contagionists depend for the mainte- 
 nance of their gloomy doctrines." 1 
 
 The great weight of the proof derived from the experience of the 
 large fever hospitals in England, Ireland, and Scotland, has been 
 well shown by Drs. Tweedie, 2 Alison, 3 Christison, 4 and Davidson, 5 
 and the last gentleman justly observes, that " the simple relation of 
 these facts would, with the majority of men, produce conviction 
 that fever was at least contagious in these hospitals, provided the 
 mind was not pre-occupied with an opposite theory." Certainly 
 none but a determined anti-contagionist could resist the fact, that, 
 in the large fever hospitals of the three countries, every clerk has, 
 during some period of his attendance, laboured under fever. 
 
 It is also ably proved by Dr. Christison, that the proportion of 
 attacks among attendants is in the ratio of their exposure to the 
 emanations from the sick. It being observed that, in the Edin- 
 burgh hospitals, they were affected in the following order as to 
 frequency. 1. Nurses. 2. Resident clerks or house-surgeons. 3. 
 House servants. 4. Medical students not attached to the service 
 of the institution. Thus, in the epidemic of 1818, of thirty-eight 
 nurses, only two or three escaped. Of the fifteen gentlemen who 
 filled the office of resident clerk between 1S17 and 1820, only two 
 escaped. 
 
 But, overwhelming as this argument from hospital experience 
 appears, some have considered it open to objections. 6 It has been 
 
 1 Medico-Chirurgical Review, vol. ii. New Series. 
 
 2 Clinical Illustrations of Fever, and Art. Fever in Cyclop, of Pract. Med. 
 s Essay on the State of the Poor in Scotland. 
 
 4 Library of Medicine. Article, Fever. 
 
 * Thackeray, Prize Essay. 
 
 6 Dr. Fergusson, Edinburgh Med. and Surg. Journal, No. 112. See also 
 a Discussion at the Royal Academy of Medicine, reported in the Medicc- 
 Chirurgical Review, Jan. 1S39, in which the opinion was advocated by MM. 
 Rochoux and Chervin, " that the disease is not communicable directly from 
 one person to another, but is only transmissible in the wav of infection, 
 
 2* 
 
100 HUDSON ON THE POISON OF FEVER. 
 
 argued, that the typhus thus received (or rather the infection of 
 typhus) is factitious, and created by causes over which we ought 
 to have exerted due control ; " that the poison can only be made 
 effective through contamination of atmosphere under long-con- 
 tinued accumulation of morbific effluvia ; and, in fine, that the 
 atmosphere of the patient is infectious, and not his person." This 
 argument receives some support from the experience of large gene- 
 ral hospitals, which, particularly in London and Bristol, give ad- 
 mission to cases of typhus without its ever being observed to spread ; 
 and, from the acknowledged rarity of communication under the 
 closest approximation among the better classes of society. It is 
 said also that M. Louis never saw a case of communication of fever 
 in an hospital, and Dr. Elliotson states that he never saw a case of 
 fever infectious. It may however be urged in reply, that the ob- 
 servations of the latter eminent observers apply to a different fever 
 — an endemial ; and that the argument proves no more than that 
 the infection of typhus is weak, compared with other infections. 
 
 But there is another kind of evidence, scarcely less decisive than 
 that derived from the records of the large hospitals. It is thus 
 somewhat flippantly disposed of by Dr. Davidson. 
 
 " In the outset it may be stated that we do not mean to fatigue 
 the reader by stories about fomites, and persons who have carried 
 the contagion about them for months or years, nor to hunt out a 
 particular individual who has conveyed it from one town to an- 
 other," <fec. 
 
 Now we think it is an admirable rule " as laid down by Dr. 
 Elliotson," 1 — u That for infection to be 'proved, the individual who 
 communicates the disease must go from the place where he resides 
 to the spot where the healthy person is, and there give it to the 
 latter. If the healthy person go to the sick person, and the sick 
 person be still in the place where he was living when attacked, 
 then no one can say that the disease which the former contracts 
 has not been produced from the situation, and not from the 
 patient. The disease may have arisen from contagion — from the 
 
 emanations of the patient — but this is not proved Whenever 
 
 such a thing occurs as disease being produced in a healthy spot by 
 the approach of an unhealthy person to a healthy one, or by the 
 application of fomites to a healthy person, then it is a proof of con- 
 tagion, provided the instances be sufficiently numerous, for one or 
 two cases may be quite accidental." 
 
 The following is a fair case of importation by both person and 
 fomites: — "A beggar from Limerick obtained admisson into a 
 labourer's cabin for herself and a dying child. In five days after 
 she quitted the cabin fever took place in one of the family, which 
 consisted of a man, his wife, and five children, and in succession, 
 Within a day or two of each other, every individual sickened, and 
 
 when the atmosphere around becomes loaded with the miasms which ex- 
 hale from the bodies of the sick." 
 1 Lectures by Rogers. 
 
HUDSON ON THE POISON OF FEVER. 101 
 
 two children from a neighbouring cabin, who had attended the 
 child's wake, took the same fever within ten days after, and com- 
 municated it to their family. The beggar {herself in good health) 
 went to a farmer's house two miles distant, and obtained a lodging 
 for the night, after her child was buried — every individual in the 
 family (rive in number) also took the fever within a few days — 
 these fevers were all severe." 1 
 
 That these cases of importation of infection occasionally exercise 
 a very great influence in the spread of fever, we are convinced by 
 our own hospital experience. From the middle of the year 1834 
 to the same period in the year 1836, scarcely a single case of con- 
 tagious typhus was admitted into the Navan fever hospital. The 
 entire number of fever cases only amounting in that time to 363, 
 and these being all instances of epidemic gastric fever or endemial 
 typhoid fever. In the month of July, 1836, three cases of a new 
 fever were admitted together. On inquiring their history, I was 
 told that one of them was the seventh of his family who had been 
 attacked — the other six having died. The two men who were 
 admitted with him came from the same neighbourhood — seven 
 miles distant — and had both had communication with the infected 
 family. These were cases of typhus with measly efflorescence, 
 profound adynamia, delirium, &c. 
 
 About two months afterwards an elderly man, with six of his 
 family, were admitted labouring under typhus fever. They were 
 from an opposite direction, about seven miles distant. The fevers, 
 of which these were the commencing cases, spread rapidly and 
 widely, and such was their effect upon our admissions, that the 
 number of fever patients increased from 363 in two years to 400 in 
 1837, and 600 in 1838; when they were at their height. While 
 these cases continued distinctly marked, and differed so much from 
 our ordinary endemial fevers, as to be recognised at once by the 
 nurses, as well as to be dreaded from their greater fatality and until 
 they became merged in the epidemic of the past year, our cases of 
 typhus were nearly exclusively derived from the districts in which 
 these originated, or to which they had spread. 
 
 Careful inquiries were made as to the source of the epidemic in 
 each case, and the following particulars were ascertained. 
 
 It appeared that in the first, a man had arrived in this country 
 from America. It was stated that the voyage had been an unusually 
 rapid one, and he had been ill the whole, or nearly the whole time. 
 On landing, he was immediately removed to his father's house, 
 twenty miles distant, and on his arrival there, was seen by a medi- 
 cal man, who pronounced his disease to be fever. He died on the 
 second day after his arrival. 
 
 His father's house and neighbourhood was previously quite 
 healthy; but in two days after his death, the father sickened, and, 
 on the day following, his sister. She communicated the disease to 
 
 1 Barker and Cheyne's Report, vol. ii. 
 
102 HUDSON ON THE POISON OF FEVER. 
 
 her husband, who lived half a mile distant. He was attended by 
 his brother, who caught the disease, and was one of the three first 
 brought into hospital. The father was visited before his death by 
 a brother, residing nearly two miles distant — on his return home 
 he sickened, and in the course of his illness communicated it to his 
 son. A brother of the importer contracted the disease, (apparently 
 from his father,) and was sent into hospital, where he died, as did 
 all the above, with the exception of the one who was sent to 
 hospital. Tn short, of the family of the importer, eight out of nine 
 were infected, and seven died. 
 
 In the course of a short time several other families, we have been 
 informed, were completely exterminated. It spread with a rapidity 
 and fatality perfectly unprecedented and long maintained its hold 
 in the town and neighbourhood. 
 
 We, of course, have no means of determining the source from 
 which the original case was derived; but we were much struck on 
 meeting with Dr. Gerhard's account 1 of the typhus which pre- 
 vailed in some parts of America in that year, with the resemblance 
 between this epidemic and that which he has so well described — 
 especially in the acrid infectiousness of both. 
 
 We have not to hunt so far for the second case. 
 
 This man's daughter was a servant in Dublin, where she con- 
 tracted typhus and died. Her brother went to see her, and remained 
 till her funeral took place. He sickened — came home, and died of 
 what was described to me as a long, spotted, fever. 
 
 After his death, the abovementioned seven persons sickened 
 within a day or two of each other, and were sent to hospital. The 
 father died; several of the others had very severe fever; typhus 
 spread from this house, first to the immediate neighbourhood, and 
 subsequently to the surrounding country. 
 
 These instances are by no means all of the kind that have 
 occurred within the time mentioned, but are selected on account of 
 their wider influence and the unequivocal nature of the testimony 
 they afford to the infectiousness of fever. 
 
 Among the most unquestionable sources of fever, is the commu- 
 nication of it by fomites carried from the patient to some place 
 previously healthy. 2 It is in this manner that washerwomen fre- 
 quently become the subjects of fever. Dr. Tweedie says, " to show 
 that the disease may be engendered by fomites in clothing, the 
 laundresses, whose duty it is to wash the patients' clothes, are so 
 invariably and frequently attacked with fever, that few women will 
 undertake this loathsome and frequently disgusting duty." 
 
 1 American Journal of Medical Sciences, February, 1837, and Dublin 
 Medical Journal, July, 1837. 
 
 2 Dr. Stark's Experiments on the Power of different Colours to absorb 
 Odorous Particles, (Edinburgh Philosophical Journal, April, 1834,) show- 
 that woollen substances constitute the most powerful fomites. 
 
HUDSON ON THE POISON OF FEVER. 103 
 
 Dr. Armstrong, 1 an anti-contagionist, had previously noticed the 
 same fact. 
 
 Dr. Reid and Dr. Cheyne, 2 inform us that, during the epidemic 
 of 1S17, not a single person of those appointed to receive the 
 clothes of the sick escaped the disease. 
 
 The preventive effects of an early removal of the sick is one of 
 the strongest proofs of infection, since the same measure produces 
 no such effect in the endemial fevers. 3 The effect of early removal 
 of the sick and the cleansing and whitewashing of their apart- 
 ments, was very remarkable in checking the progress of the disease 
 in some families, while, from the neglect of these precautions, the 
 number of the sick rapidly increased in others. Two neighbouring 
 houses, in Barrack-street, afforded an illustration of this remark, 
 viz. Nos. 41, and 47. In the former the disease began in two dif- 
 ferent families, and its progress was immediately checked by early 
 removal, cleansing, &c. In the latter, the individual first affected 
 remained at home and died of the fever, but not before he had 
 communicated the disease to eighteen persons in a short time. 
 
 On the effect of early removal of the sick, Dr. Alison 4 remarks, 
 we should have little difficulty in pointing out above a hundred 
 houses where a single case of fever has occurred, where the patient 
 had been removed speedily, and the place cleansed, and where 
 there had been no recurrence, &c. Dr. Ferriar 5 states, "that for- 
 merly, when a fever began in the Manchester Infirmary, it was 
 
 found necessary to dismiss almost all the patients but since 
 
 a few rooms were built in 1792, separated from the rest of the 
 wards, for the reception of such cases, though the infection has 
 been more than once introduced, yet by removing such patients as 
 showed symptoms of fever at their first appearance into the secluded 
 ward ; and preventing all communication between them or their 
 nurses, and the other patients and servants, the complaint has been 
 stopped ; and no reason has again occurred for a precipitate dis- 
 charge of patients." 
 
 But in applying these facts to the proof of the infectious nature 
 of fever, we are again met by the argument, that under all these 
 circumstances of crowding, &c. they only prove that a factitious 
 atmosphere of contagion is produced, and the anti-contagion ist 
 points to instances of typhus received into the Bristol and other 
 hospitals, and mingled among the other patients without ever 
 spreading the disease. 
 
 Dr. Davidson's quotation from Prichard, supports this view as 
 regards Bristol. "In St. Peter's the wards are very small, and the 
 
 1 Lectures by Rix. 
 
 2 Dublin Medical Transactions, vol. iii. ; and Dublin Hospital Reports, 
 vol. ii. 
 
 3 Report of Inspectors of House of Industry, quoted by Cheyne. Dublin 
 Hosp. Rep. vol. ii. 
 
 4 Edinburgh Medical and Surgical Journal, vol. xxviii. 
 6 Medical Histories, vol. ii. 
 
104 HUDSON ON THE POISON OF FEVER. 
 
 beds were near each other — offensive smells often perceptible — and, 
 under these circumstances, the disease manifestly contagious. In 
 the infirmary the wards are lofty and well ventilated — here also 
 the fever patients were dispersed among invalids of every descrip- 
 tion — no instance occurred of the propagation of the fever — none 
 of the nurses were attacked, nor any of the patients infected, 
 though lying within two feet of cases of typhus gravior." 
 
 Prom the infectious form of the disease prevailing almost ex- 
 clusively among the poor, it is difficult to obtain, in Ireland, a case 
 not liable to the above objections. The following is perhaps as 
 decisive, and as free from objection as may be. 
 
 In the month of March, 1839, an old man, with his son and 
 daughter — all of them persons of cleanly appearance — and in com- 
 fortable circumstances — were admitted into the Navan Fever Hos- 
 pital. The history which they gave of their seizure was, that 
 another son, the only other member of the family, had contracted 
 fever, by sleeping for two nights in a house eight miles distant, in 
 which was a person in an advanced stage of the disease. On his 
 return home, he lay down in a fever of twenty-one days. About 
 the third day after his crisis, his father sickened — on the following 
 day, his~ sister, and in a day or two after, his brother. A day or 
 two before these persons came into hospital, a young man, a cousin 
 of the parties, was admitted. He was one of a family of ten living 
 near his uncle's house. He alo?ie, of this family, visited his cousin 
 during his illness. His family showed their caution farther, by 
 sending him into hospital early in the disease. He passed through 
 the same fever (typhus, severe in all, and fatal in the old man.) as 
 the others, but no one of his large family took the disease; and on 
 inquiry, a year afterwards, I learned that they were all still free 
 from fever. 
 
 Sect. III. — Varieties in the Nature or Sources of the Poison. — 
 The dogma of Dr. Bancroft, that the contagion of typhus 1 — " The 
 original work of our common Creator must have been continued in 
 existence by the energies of a living principle, exerted successively 
 in the different bodies through which it has been transmitted from 
 one generation to another," — has met with comparatively few sup- 
 porters among late writers on fever. Elliotson, 2 Barker, 3 Roupell, 4 
 Perry, 5 and Davidson, 6 espouse this doctrine, but without adding 
 in the least to the meagre facts upon which it is founded. 
 
 On the other hand, numerous observers assert the production of 
 typhus under circumstances in which the existence of a fever poi- 
 son derived from a person labouring under the disease, was out of 
 the question ; and therefore they have assumed "that certain phy- 
 sical and moral conditions may so act on the operations of the body 
 
 1 On Yellow Fever 'Lectures, by Rogers, p. 296. 
 
 3 Dublin Med. Transactions, vol. ii. p. 595. 4 On Typhus. 
 8 Dublin Medical Journal, "Vol. 10. 6 Prize Essay. 
 
HUDSON ON THE POISON OF FEVER. 105 
 
 as to cause it to generate within itself that which produces the 
 phenomena of fever, independent of any exterior poison." 
 
 Dr. Ferriar 1 thus enumerates the circumstances, under the com- 
 bined action of which fever has been observed to arise spontane- 
 ously. 
 
 1. Want of fresh air. 
 
 2. A deficient or improper diet. 
 
 3. Want of cleanliness, and, chiefly, want of a proper renewal 
 and change of clothes. 
 
 4. Anxiety and depression of spirits. 
 
 The second and fourth of these are probably the essential causes 
 of the generation of the poison, and the others assist by producing 
 its accumulation — as in typhus — the diseased emanations consti- 
 tute the poison ; which, however, is all but harmless, unless accu- 
 mulated. 
 
 The following graphic sketch of fever, thus originating, is given 
 by Dr. J. Hunter. 3 In the month of February, 1779, I met with 
 two examples of fever in the lodgings of some poor people whom I 
 visited, that resembled in their symptoms the distemper which is 
 called the jail or hospital fever. 
 
 It appeared singular that this disease should show itself after 
 three months of cold weather. Being, therefore, desirous of learn- 
 ing the circumstances upon which this depended, I neglected no 
 opportunity of attending to similar cases. I soon found a sufficient 
 number of them for the purposes of farther information. 
 
 It appeared that the fever began in all in the same way, and ori- 
 ginated from the same causes. 
 
 A poor family, consisting of the husband, wife, and one or more 
 children, were lodged in a small apartment, not exceeding twelve 
 or fourteen feet in length, and as much in breadth. The support 
 of these depended on the daily labour of the husband, who with 
 difficulty could earn enough to purchase food necessary for their 
 subsistence, without being able to provide sufficient clothing or 
 fuel against the inclemencies of the season. 
 
 In order, therefore, to defend themselves against the cold of the 
 weather, their small apartment was closely shut up and the air ex- 
 cluded by every possible means. They did not remain long in 
 this situation, before the air became so vitiated as to affect their 
 health, and produce a fever in some one of the miserable family. 
 The fever was not violent at first, but generally crept on gradually, 
 and the sickness of one of the family became an additional reason 
 for still more effectually excluding the fresh air, and was also a 
 means of keeping a greater proportion of the family in the apart- 
 ment during the day. Soon after the first, a second was seized 
 with the fever, and in a few days the whole family perhaps were 
 attacked, one after another, with the same distemper. The slow 
 
 1 Medical Histories, vol. i. 
 
 2 Remarks on the Jail or Hospital Fever, Medical Transactions, vol. iii. 
 
106- HUDSON ON THE POISON OF FEVER. 
 
 approach of the fever, the great loss of strength, the quickness of 
 the pulse, with little hardness or fulness, the tremor of the hands, 
 and the petechias or brown spots upon the skin, to which may be 
 added the infectious nature of the distemper, left no doubt of its 
 being the same with what is usually called the jail or hospital 
 fever. It would appear there is no great power of infection in the 
 body alone provided the air be not confined. Remarking on the 
 exemption from this disease which warm countries enjoy, he says 
 — " On the cold is the cause of the air being confined which gives 
 rise to the poison, and thus, directly opposite to the opinions usu- 
 ally received, there is more danger of producing this disease in a 
 cold country, and in a cold season of the year, than in a warm 
 one." 
 
 A person exposed to, and living in the poisonous air, becomes 
 feeble and irritable, his sleep is disturbed, his tongue is white in the 
 morning, his appetite is impaired, and the smallest bodily exertion 
 quickens his pulse and fatigues him. He will remain in this state 
 for weeks together, without any formed attack of fever; yet another 
 receiving the infection from him, shall suddenly be seized with a 
 violent disease. In this manner it is, I much suspect, that prisoners 
 brought into a crowded court often produced the most dreadful 
 consequences, by disseminating the infection lodged in their clothes. 
 An instance of this kind is given by Dr. Fordyce, 1 which deserves 
 mention. Arguing for a distinction between this poison and putre- 
 factive poisons, he says — " This is undoubtedly not the case, since 
 infection has arisen from a person brought out of rooms in which 
 numbers had been confined for several months, but kept clean from 
 all putrescent matter, so that there was no particular smell or other 
 sensible quality. In one case that came under the observation of 
 the author, a person under such circumstances, from whom no 
 peculiar smell arose, or any other sensible effluvia, communicated 
 the infection to four others with whom he was carried in a coach 
 for about half a mile, so as to produce fevers in all of them, which 
 fevers were violent and fatal." 
 
 Dr. Ferriar properly includes moral causes — "because it is not 
 proved that the mere confinement of the effluvia of clean and 
 healthy persons, free from mental uneasiness can become poison- 
 ous. This view derives considerable support from the following 
 remarkable case by Dr. Harty, of the origin of fever from a single 
 person under such circumstances. 
 
 A gentleman 2 was suspected of having confined and ill-treated 
 his wife. At length two gentlemen, one of them a clergyman, 
 having obtained the necessary authority, visited the house, and ex- 
 amined every apartment for the wretched object of their humane 
 search — at first in vain ; but at length a small closet door attracted 
 their notice, and having insisted on its being opened, both gentle- 
 men eagerly entered, and as precipitately retreated. One was im- 
 
 » On Fevers, Dissertation I. page 114. * On Fevers, p. 163. 
 
HUDSON ON THE POISON OF FEVER. 107 
 
 mediately seized with vomiting ; the other (the clergyman) felt sick 
 and faint. After a little, they recruited and called the wretched 
 woman from her prison hole, in which she had been for weeks 
 immured. It was a small dark closet without light or air. and in 
 it she had been immured without a change of clothes. At the end 
 of a week both gentlemen had fever ; both took to their beds al- 
 most on the same day. The clergyman died, and the other reco- 
 vered with great difficulty after a severe struggle. Both cases 
 were alike throughout, except in the termination. The woman 
 had not then or afterwards any febrile disease, and had been free 
 from any at any period of her confinement. 
 
 Bursts of fever from this cause occur, at times, in situations 
 where no possibility of contagion from without exists — as in pri- 
 sons, in surgical hospitals, and in situations in which typhus does 
 not usually prevail and has not been introduced from without. 
 Dr. Harty gives unequivocal testimony of this fact, derived from 
 his experience in the Dublin prisons. For cases occurring in 
 crowded wards of hospitals during cold weather, we may refer to 
 Palloni, 1 Currie, 2 Tweedie. 3 
 
 Dr. Ferriar 4 gives a decisive instance of fever arising in the 
 habitations of the poor from this cause at Carlisle in 1778 — 9. 
 We must be content to refer the reader who may be desirous of 
 sifting the evidence on this much disputed question, to the above 
 writers, as a recital of the cases would occupy too much space. It 
 cannot be doubted that this depraved atmosphere has been some- 
 times considered as a source, when it really only favoured the dif- 
 fusion of the fever poison, whether emanating from the bodies of 
 typhous patients or from paludal sources. We shall have occasion 
 to recur to this subject when examining the circumstances which 
 favour the diffusion of fever as an epidemic disease. At present it 
 may be remarked that, the writers on both sides of the question, 
 have relied in some instances, upon exceptionable proofs. Thus 
 Dr. Peebles, in his valuable paper, adduces several cases which 
 occurred on board ships, which are seldom free from some of the 
 paludal sources. It is also sagaciously remarked by Lind, that it 
 is in ships going from home, and not in those returning from the 
 longest voyages, that fever is found. The reason is obvious. 
 
 But if weak cases have been adduced in proof of the origin of 
 fever from this source, they have equally been relied on by the 
 great opponent of the doctrine and his followers. Dr. Bancroft 
 has rested much of his argument upon the fact, that on board slave 
 ships, where the crowding was unprecedentedly great, fever was 
 unknown. 5 
 
 1 Quoted by Dr. Peebles, Edin. Med. and Surg. Journ. No. 125. 
 
 2 Medical Reports, page 6. 3 Clinical Illustrations. 
 4 Medical Histories, vol. i. 
 
 6 On Yellow Fever, p. 127, &c. It is worthy of notice, that in the passage 
 quoted from Dr. Liod (page 128,) the liability of felons in transports to fever 
 is asserted. 
 
108 HUDSON ON THE POISON OP FEVER. 
 
 But, as has been well observed by Dr. Fergusson, 1 there are two 
 good reasons for this. 
 
 1st. The absence of all fomites — the wretches being naked, there 
 was nothing to retain the effluvia. 
 
 2d. The high temperature, which is always destructive of the 
 poison of typhus. 
 
 The absence of fever from the huts of Fins and Russians, may 
 be explained in a similar way, by the high artificial heat, constantly 
 kept up in them, and the total absence of moisture. None of the 
 advocates of exclusive contagion, from Bancroft to Davidson, add 
 any facts to the meagre evidence upon which the argument is 
 founded. The inquiry is altogether one of the most important 
 connected with the subject of fever, and bears strongly in its con- 
 sequences upon science and humanity. 
 
 For if it appear that the poison of typhus can be generated de 
 novo, under the conjoint action of the above mentioned moral and 
 physical causes, we should institute inquiries as to the part which 
 each performs in the production of this result, and without wishing 
 11 to get rid of a difficulty" we should, on other grounds than our 
 inability to trace contagion to its primordial source, pursue the in- 
 vestigation of its laws, disregarding any such affectation of strict 
 logic as is contained in the following passage. 2 It is not intended, 
 however, to enter into any speculations respecting the primordial 
 source of the contagion of typhus, for the sources from which it, as 
 well as that of the other contagious fevers originated, are involved 
 in absolute obscurity; and though we could trace them to the most 
 remote era in antiquity, the same difficulty would be encountered. 
 Some authors, apparently to get rid of this difficulty, and to account 
 for the occurrence of typhus, where no contagion could be traced, 
 have adopted the opinion, that it may be generated by common 
 causes, such as impure air, filth, &c. and be afterwards capable of 
 propagation by contagion. The argument of analogy is directly 
 opposed to this belief for if in nature there be no exception to the 
 law, that two causes are never required to produce precisely the 
 same effect, it will follow that, whatever cause can be best recon- 
 ciled with the phenomena of typhus, must be considered the true 
 source of the disease. And accordingly this writer proceeds to 
 return a hasty verdict of " not proven," upon the claims of every 
 cause but this "one true source," contagion. 
 
 The following remark of the venerable Dr. Stokes upon this sub- 
 ject is too apposite to be passed over without notice. " This sup- 
 position of a single cause of the effects we witness, is quite unsup- 
 ported by nature. Every animal, every plant, every rock, requires 
 for its production the co-operation of many causes that we know, 
 and most probably of many more that we have not yet discovered. 
 All nature depends ultimately on a single cause, but it has pleased 
 
 'Edinburgh Medical and Surgical Journal, No. 112. 
 2 Davidson, page 2. 
 
 
HUDSON ON THE POISON OF FEVER. 109 
 
 the Almighty to cause that the effects which concern us immedi- 
 ately should arise from the co-operation of several of his creatures." 1 
 
 Again, if it appears that the febrile poison can be thus generated, 
 we need not follow Dr. Barker 2 to the Continent of Europe to look 
 for it. Nor need we to accompany 3 Dr. Lombard upon his geogra- 
 phico-typhoid tour in proof that the frieze coat of the Irish labourer 
 is its depository, in which it is exported like other " native manu- 
 factures." 
 
 But the question has a great bearing upon humanity and poli- 
 tical economy. Take the case of an epidemic such as has prevailed 
 in Ireland during the past year. Suppose that in a town contain- 
 ing a great number of poor in which fever perhaps has not yet 
 appeared, the inhabitants meet to confer upon the best preventive 
 measures. These will differ as their views of the sources of the 
 disease differ; one may suppose that the contagion is in all cases 
 imported, and can see no protection except in a " cordon sanitaire." 
 
 Another believes that fever is exclusively of endemial origin, 
 and he says — make sewers, sweep away the dung-hills — whitewash 
 the houses. 4 While the man alone who conceives the generation 
 
 1 Essay on Contagion, page 25. 
 
 * Dublin Medical Transactions, vol. ii. 
 
 3 This notion of Dr. Lombard's, along with an opinion expressed by Mr. 
 Farr, in the article Vital Statistics, in M'Cullagh's Statistics of the British 
 Empire, " that the poor Irish are keeping up, if they are not introducing, the 
 fevers of their wretched country in the heart of the British cities," has been 
 met by Dr. Cowan, and by an acute reviewer in the Dublin Medical Journal, 
 for January, 1S38. But the latter, while he confers a merited castigation 
 upon Dr. Lombard, bears too hard upon Mr. Farr, whom he classes with 
 certain humane political economists who wrote, that it would be well that 
 Ireland were sunk in the sea. And says there is not the slightest evidence 
 that the labouring classes introduce fever into the hearts of British cities. 
 Probably not. In the case of Glasgow, Dr. Stuberoh's paper, Dublin Jour- 
 nal, No. 39, would seem to show that they do not — at least by importing it. 
 But in an able and temperate reply in the second edition of M'Cullagh's 
 book, Mr. Farr has shown that, in the three great avenues by which the 
 Irish labourers enter the Kingdom — Bristol, Liverpool, and Glasgow, their 
 crowding to excess in lodging-houses, their loathsome diet and filth, are 
 productive of epidemic fever, and he concludes with the following wise 
 remarks. 
 
 " In directing attention to a weighty sanatory fact, it is far from our in- 
 tention to convey any reflection upon the Irish people. We shall, in treating 
 of epidemics, show (hat the English were formerly in as bad a condition as 
 the Irish, and we must say we had imagined that any attempt to prove that 
 England is vitally interested in the prosperity and happiness of Ireland, 
 would be rendering neither country disservice Reduce your neigh- 
 bours to ruin and starvation, and you inevitably give rise to diseases which 
 
 lower like avenging angels over your own heads So God avenges 
 
 oppression ; it reaps the fruits of its own handiwork.— (M'Cullagh's Statis- 
 tics, vol. ii. p. 529.) 
 
 * See Sanatory Reports of Poor Law Commissioners, p. 14, and Report of 
 the Select Committee on Health of Towns, p. 111. 
 
 Also the following passage from a Report of Dr. Addison's Essay on 
 Malaria, Lond. Med. Gazette, vol. iii. N. S. p. 796. 
 
 " He thought that if any palladium could be discovered potent for the 
 salvation of the city, it would be found in the shape of a scavenger /" 
 
110 HUDSON ON THE POISON OF FEVER. 
 
 of the poison under the foregoing circumstances, possibly will re- 
 commend the true prophylactics, and, by providing clothing and 
 fuel, cause the light and air to be admitted into their crowded 
 dwellings, and by relieving mind and body from the pressure of 
 impending starvation, will both render them less susceptible of dis- 
 ease if it approach them, and less capable of generating in them- 
 selves the poison which he believes may arise among them without 
 exterior communication. 
 
 On this question it is impossible to speak of humanity and poli- 
 tical economy apart. The following extract from Dr. Alison's 
 essay on the management of the poor in Scotland, will prove how 
 even motives of economy should lead to the application of the true 
 preventive relief of the wants of the poor. 
 
 " ' A fever which consigns thousands to the grave,' says Dr. 
 Harty, 'consigns tens of thousands to a worse fate — to hopeless 
 poverty ; for fever spares the children and cuts off the parents, 
 leaving the wretched offspring to fill the future ranks of prostitu- 
 tion, mendicancy, and crime.' ' The mortality of fever,' says Dr. 
 Barker, 'is most frequent where it is most injurious, viz. in men 
 advanced in life, the heads and supports of families, the increase of 
 poverty and mendicity, and the agonising mental distress to which 
 it must give rise, are consequences which must occur to every re- 
 flecting mind.' There is no exaggeration in the simple and im- 
 pressive statement of Dr. Cowan — that 'the prevalence of fever 
 presents obstacles to the promotion of social improvement among 
 the lower classes, and is productive of an amount of human misery 
 credible only to those who have witnessed it.' In the last situation 
 in which I have seen fever prevailing epidemically in Edinburgh,, 
 (new land at the foot of the old fish market close,) I find, on inquiry, 
 that five families out of the inhabitants of twelve rooms in the two 
 upper flats of the house, have been rendered fatherless by it." p. 9. 
 
 We could parallel these cases in this town, but it is unnecessary. 
 There is one more consideration arising from this subject — it is a 
 selfish one, and therefore not the least powerful — it is contained in 
 the following profound reflection of the excellent Ferrier. " The 
 diseases arising from wretchedness differ in this respect from those 
 of luxury ; the first are generally infectious, the latter solitary but 
 hereditary. This observation would furnish an excellent moral, 
 but as it is needless to suggest it, I pass on to my next point." 
 
 Sect. IV. — The Mode of Action of the Poison, and the Circum- 
 stances which assist its Operation in the Human Body. — The 
 opinions of the majority of physicians of the present day are divided, 
 as to the theory of fever, into two parties — the solidists and the 
 hu moralists. 
 
 That of the former party is thus announced in the article fever, 
 Library of Medicine, by Dr. Christison. "The theory of fever, 
 then, which seems most consonant with the whole facts, with the 
 general sentiments of the profession, especially in Britain, and with 
 a sound and prudent practice, is probably the following. Fever is 
 
HUDSON ON THE POISON OP FEVER. Ill 
 
 an essential or primary disease. The first appreciable event in the 
 chain of sequences constituting fever is a functional injury of the 
 nervous system. The only essential or invariable consequence of 
 this affection is functional derangement of most of the important 
 organs of the body, but more especially of the brain, the circulating 
 
 organs and fluid, the alimentary canal, and the skin The 
 
 changes which have hitherto been observed to take place in the 
 blood and other animal fluids, are, like the local disorders, secon- 
 dary and not primary. They may be the source of the phenomena 
 remarked in the advanced stage of the disease, but they are not the 
 source of the disease itself in the first instance." 
 
 If we turn to another recent work of high authority, we find the 
 very reverse order of sequence is maintained. "It appears pro- 
 bable, if not certain, from what has been advanced, that in a certain 
 class of fevers (typhoid) the blood is primarily diseased, and that 
 certain changes in one or more organs take place as a consequence 
 or secondary effect." 1 
 
 It will be seen that neither of these distinguished writers assigns 
 the phenomena of fever exclusively to his system ; and it has been 
 well remarked, "that all febrile disturbances are disturbances of 
 such vital actions as are the joint product of these two great factors 
 of vital phenomena — for example, the primary phenomena of all 
 fevers are — 1. Disturbance in the formation of animal heat ; 2. 
 Disturbance in all the secerning functions ; 3. Disturbance in the 
 process of nutrition. But the formation of animal heat, secretion, 
 and the nutritive process, are all dependent on the conjoint action 
 of the nerves and bloodvessels. Either of these two systems may 
 receive the first morbific impression, but the one soon participates 
 in the changes of the other." 2 
 
 This last sentence involves the proper terms of the controverted 
 question, for, while all must admit that the phenomena of fever 
 established are due to the conjoint operation of the nervous system 
 and the blood, the solidists maintain that it is upon the nervous 
 system the morbific impression of contagion acts primarily ; while 
 the advocate of a modified humoral theory holds that the source 
 and primary seat of typhus fevers, properly so called, is proved to 
 be in the blood ; and that the order of sequence is, first, a vitiation 
 of the blood by the commixture of deleterious substances ; next, in 
 consequence of such vitiation, an alteration of the functions of the 
 nervous system ; and, lastly, the blood that supports the organs, 
 and the nervous system that animates them, having suffered a 
 general injury, a constant though not always appreciable modifi- 
 cation of these organs in their function or in their texture." 
 
 The advocates of each theory construe the phenomena of the 
 latent period in accordance with their peculiar views : thus, while 
 the humoralist regards it as the time intervening between the ab- 
 
 1 Dr. Tweedie. Art. Fever. Cyclopaedia of Practical Medicine. 
 3 Ferguson on Diseases of Women. Part 1. p. 97. 
 
112 HUDSON ON THE POISON OF FEVER. 
 
 sorption of the poison and the manifestation of its effects on the 
 great nervous centres — the advocates of the opposite theory con- 
 sider that u the symptoms which characterise this period, whether 
 they be slight, or whether they be severe, indicate a disturbance 
 affecting primarily the nervous system. 1 
 
 Again, — " We are not of opinion that the time between exposure 
 to contagion and the formation of the disease thereby caused, is a 
 period of health : the nervous system was affected previous to any 
 disorder of the circulating system." 2 
 
 From these extracts it will be seen that it is to the explication of 
 the phenomena of the access and latent period of fever, and not to 
 the formed disease, that each theory is to be applied, and its agree- 
 ment with these phenomena tested. 
 
 This narrowing of the question deprives the humoralist of all 
 support from the fact of changes detected in the blood subsequent 
 to the latent period, since these may be owing to the changes in the 
 nervous system ; while, on the other hand, it reduces the available 
 arguments for the nervous theory to two. That from the analogy 
 of the morbific impression of contagion to the action of certain poi- 
 sons — " such instantaneousness of action being supposed to be in- 
 compatible with the previous absorption of a poison into the circu- 
 lation ;" and, that deduced from the fact, that " a single mental 
 shock often produces protracted disease, without the presence of 
 any known source of the febrile poison." 
 
 By thus limiting the dispute, much is given up by the humor- 
 alist ; since he holds, '• that the fluidity or diffluence of the blood, 
 and the violent colour observed in typhus, is not the result of the 
 disease, but, on the contrary, that they are the immediate effects of 
 the specific cause of the fever ;" 3 while, on the contrary, it is on the 
 phenomena of the access that the very strongest arguments for the 
 nervous theory are founded. 
 
 Passing by the many writers who have rested satisfied with sta- 
 ting their opinions of the origin of fever, without giving the grounds 
 upon which they are founded, we shall examine the arguments for 
 the nervous theory contained in Sir H. Marsh's able paper on the 
 Origin of Fever, 4 which are rested upon a number of histories of 
 the access of the disease, which Dr. Tweedie has pronounced to 
 "contain a body of evidence which should alone decide the ques- 
 tion of the contagiousness of fever." 
 
 It will be our endeavour, as advocating a humoral theory, to 
 show that the evidence does not support the conclusions of its dis- 
 tinguished author. These conclusions are founded upon a sup- 
 posed analogy of the morbific impression of contagion (or infection) 
 
 1 Marsh. Dublin Hospital Reports, vol. iv. 
 
 2 Barker and Cheyne's Report. 
 
 3 Vide Rostan's Clinlical Lectures on Typhoid" Fever, in Johnson's Re- 
 view for January, 1841. 
 
 4 Dublin Hospital Reports, vol. iv. 
 
HUDSON ON THE POISON OF FEVER. 113 
 
 to the action of certain powerful narcotic poisons which is sup- 
 posed to be exerted upon the nervous system immediately, and not 
 through the circulation. " Though there can be little doubt," says 
 he, " that prussic acid, when applied to the surface of the body, is 
 ultimately absorbed, yet the rapidity of its action leads to the con- 
 clusion, that its first and instantaneous effect is on the nervous sys- 
 tem." And Dr. Law, in arguing for a mental origin in one of his 
 cases, in which the person was exposed to contagion before and at 
 the time of seizure, says, " How are we to explain the mode of this 
 individual's attack of fever ? If we are to suppose it was contracted 
 from exposure to contagion, we would avail ourselves of the argu- 
 ment of the toxicologist, who reasons that, from the very short pe- 
 riod of time in which some poisons exhibit themselves in the 
 system, these poisons affect the system through the medium of the 
 nerves, rather than through the circuitous route of the circulation." 
 
 This theory of poisons being assumed, the analogy of the action 
 of infection is thus stated by Sir H. Marsh. " From these facts it 
 appears that the poison of contagion produces its effects with the 
 same rapidity as the narcotic poisons to which we have alluded. 
 Headache, debility, sickness of stomach or vomiting, are among the 
 symptoms first perceived; these sensations, with the rapidity of an 
 electric shock, are at the instant produced," &c. 
 
 This specious argument from analogy will be somewhat weak- 
 ened by the following considerations : — 
 
 1. It is by no means proved, that any poison, however rapid, 
 produces its effects upon the system, without being received into 
 the general circulation, or before it can be carried to the brain 
 through the medium of the circulation. 
 
 Miiller's 1 conclusion upon this question is — " These experi- 
 ments, as well as many others instituted by well-known physiolo- 
 gists, prove that, before narcotic poisons can exert their general 
 effects on the nervous system, they must enter the circulation." 
 And again — " The rapid effects of prussic acid can only be ex- 
 plained by its possessing great volatility and power of expansion by 
 which it is enabled to diffuse itself through the blood more rapidly 
 than that fluid circulates ; to permeate the animal tissues very 
 quickly, and in a manner independent of its distribution by means 
 of the blood, and thus to produce the peculiar material changes in 
 the central organ of the nervous system more rapidly in proportion 
 as it is applied nearer to it." But even this explanation of Mullens 
 — while it falls very far short of furnishing the desired analogy — 
 would seem incorrect, since Mr. Blake has found that the poisonous 
 effects of prussic acid in a large dose introduced into the stomach 
 will not take place so long as the circulation through the vena 
 porta is carefully interrupted. He even found that, on the effects 
 of the poison being produced by removing for an instant the im- 
 pediment to the circulation, the animal could be recovered upon 
 
 1 Elements of Physiology, by Baly, vol. i. p. 246. 
 4 — d 3 hudson 
 
114 HUDSON ON THE POISON OF FEVER. 
 
 the circulation being again stopped, though the three drams of 
 prussic acid were still in the stomach. Blake's conclusions from 
 his interesting experiments are 1 — 
 
 i. That the time required by a substance to permeate the capil- 
 lary vessels may be considered as inappreciable. 
 
 2. That the interval elapsing between the absorption of a sub- 
 stance by the capillaries and its general diffusion through the body 
 may not exceed nine seconds. 
 
 3. That an interval always more than nine seconds elapses be- 
 tween the introduction of a poison into the capillaries or veins and 
 the appearance of its first effects. 
 
 4. That if a poison be introduced into a part of the vascular sys- 
 tem nearer the brain, its effects are produced more rapidly, 
 
 5. That the contact of a poison with a large stirface of the body 
 is not sufficient to give rise to general symptoms, as long as its 
 general diffusion through the body is prevented. 3 
 
 But secondly — the suddenness of action of the febrile poison is 
 generally speaking only apparent and not real. 
 
 The infection of continued fever (says Christison) is, for the most 
 part, by no means virulent. And again — fever is usually commu- 
 nicated by long exposure to the emanations from the sick, and sel- 
 dom by any single short exposure, however decided. It is a common 
 notion that single, brief, decided exposures often occasion an attack; 
 and, in support of this notion, reference is made to cases where 
 
 1 Edinburgh Medical and Surgical Journal, vol. 53. 
 
 2 Sir H. Marsh states, that-in some experiments performed by himself and 
 Dr. Jacob, the poisonous effects of prussic acid were observed to commence 
 in five seconds ; there is therefore a discrepancy between his results and 
 those of Mr. Blake, but the following experiment of the last gentleman 
 would seem to show that even this short time would allow of the entrance 
 of the poison into the circulation. 
 
 "A dram of the strongest liquor ammonias, mixed with five drams of wa- 
 ter, was injected into the jugular vein of a dog. A glass rod which had 
 been dipped in hydrochloric acid, was held immediately under the nostrils j 
 four seconds after the introduction of the first drop of the solution of ammo- 
 nia into the vein, it was plainly detected in the air expired from the lungs, 
 by the white vapours that were formed upon its coming in contact with the 
 vapour of the hydrochloric acid." 
 
 Dr. Christison's experiments on prussic acid (at page 657 of his work orj 
 poisons,) do not support Sir II. Marsh's views of the extreme rapidity of 
 action of this poison. While at page 660 he admits that every argument 
 but this is in favour of the theory of its action through the blood, in which 
 it was detected by analysis in the case of a cat killed in a (ew seconds by 
 the acid applied to the tongue. 
 
 But in the text I have neglected to notice the fact, so prejudicial to Dr. 
 Marsh's analogy, that the blood in these cases of sudden poisoning is fluid. 
 We are also told by Dr. Christison, that in cases of sudden death from the 
 emanations from Parisian privies, the blood is found black and fluid. 
 
 A similar effect is observed in cases of sudden death from other kinds of 
 miasm — for an instance from animal putrefaction, see the Medico-Chirur- 
 gical Review, for January, 1825; and for an instance from marsh miasm, 
 see Evans on the Endemic Fevers of the West Indies, p. 22. 
 
HUDSON ON THE POISON OF FEVER. 115 
 
 individuals can trace the infection, as they imagine, to a particular 
 fever patient, by having experienced some very peculiar morbid 
 sensation at the time of exposure. There is much room for fallacy, 
 however, in observations of this kind, and besides their proportion 
 is small compared with the far more numerous instances where no 
 such sensations can be recalled as having ever been experienced. 
 
 It is unnecessary, though it would be most easy, to multiply tes- 
 timony to the same effect. Even Dr. Marsh says very truly, that 
 "by far the greater number of patients labouring under contagious 
 fever, are not at all aware of the circumstances connected with the 
 origin of their complaint ; the impression made at the time of their 
 exposure being in general unheeded or forgotten. Indeed the im- 
 pression is often times so slight, as to lead one to think that conta- 
 gion does no more than predispose to fever, and determine the 
 nature of the disease, of which, exposure to cold, fatigue, or some 
 such accidental circumstance, is the immediately exciting cause ; 
 so that there appears much reason to believe that, many are so 
 mildly affected, that were it not for the superaddition of an exciting 
 cause, they would altogether escape fever; hence it happens that 
 numbers affected with contagious fever, trace the origin of their 
 complaint exclusively to cold, wet and other exciting causes of the 
 disease, the time and circumstances of exposure to contagion hav- 
 ing been entirely forgotten. Cases of this kind, ivhich are by far 
 the most numerous, Throw but little light on the origin of fever. It 
 is only by a careful observation of facts of occasional and rare oc- 
 currence, such as those recorded in this paper, in which the effects 
 of contagion are well marked and striking, that we can hope to ob- 
 tain certain and satisfactory results." 
 
 There is much truth in the foregoing passage, especially in that 
 part of it which assigns to contagion the action of a predisposing 
 cause ; but how can this view be reconciled with Dr. Marsh's own 
 theory, that the action of contagion is an "injurious impression 
 upon the sentient extremities of the nerves?" and how far is he 
 justified in assigning; the cause and commencement of fever to sud- 
 den and brief exposure, even by cases of rare occurrence, (excep- 
 tions he admits to the general rule), such as he has collected? 
 These are questions deserving consideration. We shall return to 
 the first, when examining the argument for the humoral theory, 
 derived from the latency and cumulative property of the poison ; 
 but how do Dr. Marsh's cases support his opinions as to sudden 
 exposure being the cause of fever? It is obvious that when it is 
 committed, that the general rule is, "that no perceptible impression 
 is made by contagion ;" we cannot admit the conclusion that the 
 impression was the cause of the disease, except it appears that no 
 other exposure took place; the more so, since the medical and 
 other attendants of fever patients in private houses, and where 
 cleanliness and ventilation are properly observed, frequently per- 
 ceive these impressions — arising from the odour of the patient or 
 his excretions ; — such impressions, however sickening at the time, 
 
 3* 
 
116 HUDSON ON THE POISON OP FEVER. 
 
 seldom leading to any further ill consequences ; but of twenty-two 
 cases adduced by Dr. Marsh, ten were nurses or porters of fever 
 hospitals, seven were physicians, one a clergyman, and one appears 
 merely to have suffered the nervous shock, as fever did not follow. 
 
 The remaining three appear to be unexceptionable instances of 
 fever, arising from a single and concentrated dose of the poison ; 
 two, if not all of them, being cases of communication by fomites, 
 (usually containing a concentrated poison.) 
 
 But again, we have to inquire whether the moment of exposure 
 was that of the commencement of the fever? since the argument 
 rests mainly on "such instantaneousness of action of the poison as 
 is incompatible with the idea of absorption into the blood." Here 
 we might remark on the rapid diffusion of gaseous poisons through 
 the blood, and appeal to Mr. Blake's experiments in proof that the 
 poison may enter the circulation even before the impression is felt ; 
 but admitting that this impression is a purely nervous one — a shock, 
 or "reaction," as it has been termed — u a resistance offered by the 
 vital powers to chemical action" — it is not the commencement of 
 fever. For it may end where it began ; the impression may not, 
 and very often is not followed by fever ; and in many more cases 
 goes off altogether for a longer or shorter period before fever com- 
 mences. True, it may continue, especially in persons whose ima- 
 gination has become alarmed — in which case some writers have 
 attributed the imagination to the influence of the poison upon the 
 nervous system — and, in a manner hereafter to be explained, it 
 may shorten considerably the latent period ; but we repeat, this 
 latent period will be found to exist in any case in which a -previous 
 imbibition of infection is not to be admitted. "The symptom," 
 says Sir H. Marsh, "which is generally considered to mark the 
 commencement of a febrile movement in the system, is that com- 
 motion of the nervous functions which has been technically termed 
 a rigor" This commencement of the febrile movement is only 
 mentioned in twelve of his cases, and in these it occurred in four 
 at an interval of from one to two days, in six after several hours, 
 and in two only it is said to have come on "a short time after" ex- 
 posure to the poison. 
 
 The third consideration which may be urged against this analogy 
 is, "that the poison with which contagion is compared is not repro- 
 duced.'' 1 As this reproduction of contagion is one of the strongest 
 arguments for the humoral theory, we shall not dwell upon it here, 
 but merely observe that the toxicological argument, while it sets up 
 a forced and false analogy with poisons which are not reproduced, 
 strives to weaken and destroy that which naturally exists between 
 the infection of typhus and that class of morbid poisons to. which it 
 may be said to belong— the exanthemata. This has not escaped 
 Dr. Marsh's observation, who admits that "the opinion that to 
 maintain a protracted fever, an internal cause of disease (such as 
 absorbed or generated morbid matter) is necessary, would arise 
 from the phenomena which manifest themselves in the course of 
 
HUDSON ON THE POISON OF FEVER. 117 
 
 an exanthematous fever." But he meets this by the second of the 
 objections we have enumerated to the humoral theory. 
 
 "Yet that to excite and maintain continued fever, an abiding 
 cause is not necessary, might be proved in various ways, but the 
 fact that a single mental shock often produces protracted disease, 
 is decisive upon this point." 
 
 As Sir H. Marsh adduces no fact in support of the above asser- 
 tion, turn we to another able physician who, in a recent paper, 
 adduces seven cases from his own experience, in proof of the 
 opinions expressed in the following passages :' — 
 
 " We quite agree in the wisdom of the precaution of satisfying 
 the absorbents, but deny that they are more the channels through 
 which the morbific matter enters the system, in this instance, (fever 
 from contagion,) than they are in other cases where there is no 
 reason to suppose either that they are in an unusual state of activity, 
 nor if they were, can we discover any contagion to serve as ^materies 
 morbi for them to exercise themselves upon. These are cases in 
 which a strong moral impression acts as a direct and immediate 
 cause in the production of a fever, similar in all respects to one 
 from contagion," &c. 
 
 And again : — 
 
 " We shall proceed to detail some cases of fever which seem to 
 us calculated to throw some light upon the mode in which the first 
 morbid impression is made upon the system in the production of 
 the disease ; and see how far these cases tend to confirm the opinion 
 that fever is the result of a miasma conveyed to the system by the 
 absorbents: or if it be not, in some cases at least, the effect of a 
 moral impression acting upon the nervous system, and exhibiting 
 itself in symptoms indicating a derangement of the functions of this 
 system." 
 
 The advocate for the theory of absorption may reasonably re- 
 quire that in such cases the materies morbi shall not appear to 
 have been within reach. But of five cases, the subjects were ex- 
 posed to infection at or before the seizure. The sixth was not (as 
 Dr. Law admits) a case of fever ; and we have only one in which 
 fever followed a mental shock, without evidence of infection at the 
 same time existing. To explain away this case, a determined 
 opponent of the nervous theory might adduce evidence of the 
 general diffusion of the fever-poison through the atmosphere of a 
 city, when fever is prevalent in it; he might maintain that at such 
 times 2 "certain changes take place in the constitution of the atmo- 
 sphere imperceptible to our senses, and eluding chemical tests, 
 which predispose human bodies to febrile diseases in such a way, 
 that circumstances which in ordinary times would only give rise 
 to a catarrh, an attack of rheumatism, or even occasion no indispo- 
 
 1 Observations on Fever, by Dr. Law. Dublin Med. Jour., vol. xiv. 
 
 2 Prichard on the Epidemic Fever of Bristol. 
 
118 HUDSON ON THE POISON OF FEVER. 
 
 sition at all, will now in many individuals become the exciting 
 causes of continued fever." 
 
 If it be said that this is begging the question, the humoralist takes 
 higher ground, and asserts that such cases, instead of disproving, 
 strengthen his own theory; inasmuch as he can show that fever 
 follows strong nervous impressions, in consequence of their lower- 
 ing the vitality of the blood, and so favouring the transformations 
 in that fluid upon which fever depends. He believes that 1 "no 
 other component part of the organism can be compared to the blood 
 in respect of the feeble resistance which it offers to exterior influ- 
 ences. The blood is not an organ which is formed, but an organ 
 in the act of formation ; indeed, it is the sum of all the organs 
 which are being formed. The chemical force and the vital prin- 
 ciple hold each other in such perfect equilibrium, that every dis- 
 turbance, however trifling, or from whatever cause it may proceed, 
 effects a change in the blood. Every chemical action propagates 
 itself through the mass of the blood; for example, the active 
 chemical condition of the constituents of a body undergoing de- 
 composition, fermentation, putrefaction or decay, disturbs the equi- 
 librium between the chemical force and the vital principle in the 
 circulating fluid : the former obtains the preponderance. Numerous 
 modifications in the composition and condition of the compounds 
 produced from the elements of the blood, result from the conflict of 
 the vital force with the chemical affinity in their incessant endea- 
 vour to overcome one another." 
 
 He admits that 2 "perhaps there are cases in which the modifica- 
 tion of the blood is only secondary to a modification of the nervous 
 system. Tf, for instance, under the influence of a strong mental 
 emotion, this system, being suddenly perverted in its action, ceases 
 to exert its proper influence over the different organs in which the 
 blood is elaborated, deposited, and receives new materials, must not 
 that fluid itself become altered in its turn ? If so, thence must arise 
 a number of organic and functional derangements varying greatly, 
 according to the mode and intensity of the primitive alteration of 
 the innervation. In such cases we may observe to occur spora- 
 dically those same diseases, typhoid or other, that we have just now 
 seen prevailing epidemically under the influence of manifest causes 
 of infection of the blood." 
 
 To prove that Dr. Law's case belongs to this 'formula, let us place 
 it by the side of another in which precisely the same mental im- 
 pression, acting more intensely, produced death. Eliza J , eet. 
 
 twenty-six, was admitted under Dr. Law's care, March 28, 1836. 
 She had been in perfect health a week since, when, on missing a 
 piece of linen which had been committed to her care to make shirts, 
 from the apprehension that her honesty would be called in question, 
 
 1 Liebig, p. 360. 
 
 2 Andral, Pathological Anatomy, vol. i. p. 671. 
 
HUDSON ON THE POISON OF FEVER. 119 
 
 she was seized with a violent rigor and sickness, which confined 
 her to bed ever since. Petechial fever, with prominent hysterical 
 symptoms, followed. She recovered with difficulty and slowly. 
 
 Some time ago, I was present at the examination {post mortem) 
 of a man who died suddenly under the following circumstances. 
 
 He had committed a very trifling theft, for which he was appre- 
 hended and carried before a magistrate. He was a person rather 
 above the lower order, and manifested great shame and grief at this 
 exposure. While sitting before a table waiting for his case to be 
 called on, he leaned his head forward on the table, and was observed 
 to snore ; in a few minutes, the sound of his breathing ceased, and 
 on raising his head, those near him found that he was dead. It 
 was supposed that apoplexy was the cause of death, and the brain 
 was first examined. It was, however, perfectly healthy. The 
 other viscera were then carefully examined. The only one which 
 discovered any thing which could account for his sudden death, 
 was the heart, which was distended with dark fluid blood. 
 
 Let us suppose that the mental impression had not been so intense 
 in this case, and the life of the blood not so completely and sud- 
 denly destroyed — what would have been the probable consequence? 
 This question is answered by a comparison of the two histories. 
 In the last, the vitality of the whole circulating mass was destroyed, 
 and the symptoms were those of a brain suffering the influence of 
 a strong- narcotic poison. In the other, the livid, petechias, spongy, 
 and bleeding gums, &c, showed to what an extent the vitality of 
 the blood had been destroyed. The immediate occurrence of a 
 rigor showed that the self-generated poison had reached the nervous 
 centres, and that the struggle had commenced which was to end 
 with either the death of the whole mass of blood, or the elimination 
 from it of the portion so affected. It is worthy of remark, (and is 
 noticed by Dr. Law,) that the rigor was immediate — not after an 
 interval of hours or days, as in cases of exposure to infection, in 
 which the operation of the poison is gradual and often (generally, 
 indeed,) accumulative. 
 
 In fine, typhus, or a disease resembling it, but differing, according 
 to Dr. Cheyne, in the very important particular that it is not com- 
 municated by contagion — in other words, that the poison is not re- 
 produced — is but one of three modes, or degrees, in which the blood 
 suffers from a strong mental impression. It may be killed at once, 
 or it may suffer in a degree insufficient to produce/b?'mec/ disease — 
 loss of appetite and depraved secretions, with slight derangements 
 of animal heat, being perhaps the only indications of the injury it 
 has received — or it may act upon the system in a manner similar to 
 the fever poison. But this cannot be said to prove that the fever 
 poison acts by producing a moral impression ; and, therefore, in- 
 stead of agreeing with Dr. Law, that "even in cases where there 
 was most reason to suspect absorption, where a person having ex- 
 posed himself to contagion, fasting — and then contracted the dis- 
 ease — even here the symptoms exhibited by the disease so resemble 
 
120 HUDSON ON THE POISON OF FEVER. 
 
 those where there is no possibility of suspecting infection, that we 
 cannot but believe that the mode of absorption is the same in both 
 cases, and that as it is not absorption in the one case, neither is it 
 in the other" — instead of going to this length ot denying the exist- 
 ence of a materies morbi altogether, we would reduce the two 
 cases to the same formula by an opposite method. As thus : vio- 
 lent nervous shocks kill the blood or modify it ; and occasionally 
 produce fever. Contagious and other miasms also, in some rare 
 instances, kill the blood, and, in general, modify it, so as to produce 
 fever. But they may do so without causing a nervous shock. 
 Therefore, they act directly on the blood, by being absorbed into 
 that fluid, and not through the intervention of any derangement, 
 functional or otherwise, of the nervous system. 
 
 The principal arguments for the nervous theory derived from the 
 mode of access of fever, having been examined, we shall submit 
 some of those which tend to support a modified humoral theory, 
 and then offer a rationale of the action of the causes of fever in 
 accordance with this theory. 
 
 The explication of the accession of the disease having been taken 
 as a text of the opposite theories, we are deprived of any support 
 from two arguments which have been much used by humoralists: 
 viz. the changes which the blood undergoes in the course of fever, 
 and the production of fever or a disease perfectly analogous, by the 
 introduction of substances into the circulation. 
 
 Another argument, of a similar kind, is derived from the known 
 power of sources which ordinarily produce fever, to kill the blood 
 at once when their poison is introduced into it in sufficient quan- 
 tity. We give the fact on the highest authority. 1 The inference 
 has been met by the toxicological argument already considered, 
 and by a distinction asserted between mephitic poison and the 
 fever poison. This distinction we shall examine, along with the 
 source itself, hereafter. 
 
 But there are certain peculiarities in the action of the febrile poi- 
 son which in their general character resemble other morbid poisons, 
 and favour the idea of its absorption into the blood. 
 
 The first of these is its occasional latency in the system, in which 
 it will lurk for a longer or shorter period, until called into action 
 by some accidental cause. 
 
 "In several instances," says Dr. Graves, 3 "I have observed that 
 certain diseases, which seemed to have been lurking in the consti- 
 tution, may suddenly make their appearance in consequence of the 
 operation of causes apparently unconnected with the disease in 
 
 question T have witnessed several bad cases of bad secondary 
 
 venereal, in which the attack was traced to excessive fatigue, or a 
 common cold. You will also meet numerous examples of an 
 analogous fact among fever patients : examine them, and you will 
 
 1 Christison on Poisons, p. 700, 2d edition. 
 
 2 Lectures, London Medical Gazette, vol. iii. N. S. p. 186. 
 
HUDSON ON THE POISON OF FEVER. 121 
 
 learn that in a majority of cases their disease arose from exposure 
 to cold. One person fatigues himself by too much exertion in 
 business, and gets an attack of spotted fever; another attributes his 
 disease to over anxiety ; some to intemperance, and some to fright. 
 In all these cases, it is very probable that the poison of fever has 
 been lurking for some time in the system, and has been called into 
 active existence by the operation of some sudden accidental cause, 
 as fright, fatigue, intemperance, or cold." 
 
 Something similar, Dr. Graves justly observes, is remarked in 
 the case of the Irish labourers employed during summer and 
 autumn among the fens of Lincolnshire (and we may add Cam- 
 bridgeshire.) During their stay in England, they appear free from 
 disease ; but on their return home, if they happen to be exposed to 
 wet, fatigue, or the derangements of health consequent on intemper- 
 ance, they are very often seized with intermittent fever. 
 
 He continues, " Does it not often happen, that many of us escape 
 fever although exposed to its contagion month after month ? Do 
 we not go on for years untouched, although subject every-day to 
 the imbibition of the poison ? and do we not, rendered bold by our 
 impunity, consider ourselves, as it were, fever proof, until some 
 accidental cause convinces us of the contrary, by giving rise to a 
 sudden and violent attack? Who is there that has not observed 
 this repeatedly among the students attending a fever hospital ?" 
 
 Similar proof of the latency of the fever poison is afforded by the 
 cases recorded by Lind, of sailors, who apparently escaping from 
 the fever which was raging on board, went ashore, and in some 
 time afterwards, in consequence, apparently, of exposure to cold or 
 debauchery, were attacked, not with the fever prevailing there, but 
 with that of the ship they had left. In this respect, then, the febrile 
 poison resembles other morbid poisons. 
 
 A^ain : it is a cumulative poison. The exposure of a single 
 moment is probably insufficient, in any case, to cause fever. A 
 few inspirations may accumulate sufficient in cases of great con- 
 centration of poison; but there is abundant proof that daily and 
 continued imbibition of the poison is, in general, requisite.- Thus, 
 we find the attendants on the sick attacked in proportion to the fre- 
 quency of their approaches to the infection, the very reverse of what 
 would be the fact if the poison were not cumulative, since it is a 
 law constantly observed, that agents which act by single impres- 
 sions lose their power of producing those impressions in proportion 
 as they are frequently repeated. It is true that some eminent wri- 
 ters aver this of infection, as Dr. Copland, who says, "when a 
 person has escaped infection upon the first or the earlier exposures 
 to several infectious maladies, he will generally continue to possess 
 an immunity, unless circumstances should occur to increase his 
 predisposition." Observations made on a large scale, however, 
 tend to disprove this, as regards typhus. 
 
 Thus, when fever prevailed during the retreat of the British 
 
122 HUDSON ON THE POISON OF FEVER. 
 
 army through Holland, we are informed by Dr. Fergusson, 1 that 
 few, indeed, of the medical staff escaped the typhoid contagion ; and, 
 again, in the retreat from Talavera to the confines of Portugal, it 
 was seen that the best seasoned of the medical staff were the prin- 
 cipal sufferers. Dr. Christison, too, 2 (a solidist) maintains that it is 
 not improbable that the severity of the disease bears some proportion 
 to the amount of exposure. 
 
 And "In many instances, fever breaks forth apparently 
 
 from gradual charging of the constitution under constant exposure 
 to the morbid emanations, and without any other co-operating 
 cause." 
 
 This is very like humoralism, as is the illustration given by Dr. 
 Haygarth. ;t A pint of yeast will excite fermentation in a barrel of 
 ale, but a hundredth or a thousandth part would not have the same 
 effect." 
 
 Again. The reproduction of the poison of contagion, is a fact 
 "not dreamt of" in the philosophy of the solidists. Here their 
 analogy is at fault, for the poisons from whose action it is derived 
 are not reproduced. Neither will any supposable impression upon 
 the nervous system explain the continued reproduction of the same 
 febrile phenomena, and the same miasm through an indefinite series 
 of individuals. We have admitted the production of fever by a 
 strong mental impression. We have endeavoured to reconcile this 
 occurrence with the theory which refers the source of fever in all 
 cases to the blood. We have, however, noticed the fact, that such 
 fever does not reproduce itself, and referred to the testimony of one, 
 whose accuracy of observation has seldom been surpassed, who 
 says, ' ; The most remarkable part of the disease is that it does not 
 spread. I have no recollection of a second case of this kind of 
 fever occurring in a family." 3 
 
 But the humoral theory has its analogy for the reproduction of 
 the poison. 4 " The mode of action of a morbid virus, exhibits such 
 a strong similarity to the action of yeast upon liquids containing 
 sugar and gluten, that the two processes have been long since com- 
 pared to one another, although merely for the purpose of illustra- 
 tion. But when the phenomena attending the action of each re- 
 spectively, are considered more closely, it will in reality be seen 
 that their influence depends on the same cause." 
 
 N >w, when yeast is introduced into a mixed liquid, containing 
 both sugar and gluten, such as wort, the act of decomposition of the 
 sugar effects a change in the form and nature of the gluten, which 
 is in consequence also subjected to transformation. As long as 
 some of the fermenting sugar remains, gluten continues to be sepa- 
 rated as yeast, and this new matter, in its turn, excites fermeuta- 
 
 1 Edinb. Med. and Surg. Journal, No. 112. 
 
 2 Library of Medicine, Art. Fever. 
 
 3 Dr. Cheyne's Account of B^ver from Mental Causes, in Sir H. Marsh's 
 Paper on the Origin of Fever. 
 
 * Liebig. 
 
HUDSON ON THE POISON OF FEVER. 123 
 
 tion in a fresh solution of sugar or wort If the sugar, however, 
 should be first decomposed, the gluten which remains in solution, 
 is not converted into yeast. We see, therefore, that the reproduc- 
 tion of the exciting body here depends : — 
 
 1. Upon the presence of that substance from which it was 
 originally formed. 
 
 2. Upon the presence of a compound, which is capable of being 
 decomposed by contact with the exciting body. 
 
 If we express, in the same terms, the reproduction of contagions 
 matter in contagious diseases, since it is quite certain that they 
 must have their origin in the blood, we must admit that the blood 
 of a healthy individual contains substances, by the decomposition 
 of which the exciting body or contagion can be reproduced. It 
 must further be admitted, when contagion results, that the blood 
 contains a second constituent, capable of being decomposed by the 
 exciting body. It is only in consequence of the conversion of the 
 second constituent, that the original exciting body can be repro- 
 duced. 
 
 When a quantity, however small, of contagious matter, that is of 
 the exciting body, is introduced into the blood of a healthy indivi- 
 dual, it will be again generated in the blood just as yeast is reproduced 
 from wort. Its condition of transformation will be communicated 
 to a constituent of the blood ; and in consequence of the trans- 
 formation suffered by this substance, a body identical with or 
 similar to the exciting or contagious matter, will be produced 
 from another constituent substance of the blood. The quantity of 
 the exciting body newly produced, must constantly augment, if 
 its further transformation or decomposition proceeds more slowly 
 than that of the compound in the blood, the decomposition of which 
 it effects." 
 
 These substances are the organic matters existing in the blood, 
 either in the state of transition from blood into the constituents of 
 the tissues, or from food into blood. Which changes, it is argued, 
 .cannot take place without the formation in the blood of new com- 
 pounds, which require to be removed by the organs of excretion. 
 
 " When the organs of secretion are in proper action, these sub- 
 stances will be removed from the system ; but when the functions 
 of these organs are impeded, they will remain in the blood, or be- 
 come accumulated in different parts of the body. The skin, lungs, 
 and other organs, assume the functions of the diseased secreting 
 organs, and the accumulated substances are eliminated by them. 
 If when thus exhaled, they happen to be in the state of progres- 
 sive transformation, these substances are contagious, that is, they 
 are able to produce the same state of disease in another healthy 
 organism, provided the latter organism is susceptible of their 
 action ; or in other icords, contains a matter capable of suffering 
 the same process of decomposition. 
 
 "In the abstract chemical sense, reproduction of a contagion 
 
124 HUDSON ON THE POISON OF FEVER. 
 
 depends upon the presence of two substances, one of which becomes 
 completely decomposed, but communicates its own state of transfor- 
 mation to the second. The second substance thus thrown into a 
 state of transformation, is the newly formed contagion. 
 
 " The second substance must have been originally a constituent 
 of the blood ; the first may be a body accidentally present. 
 
 " If both be constituents indispensable for the support of the vital 
 functions of certain principal organs, death is the consequence of 
 their transformation. But if the absence of the one substance, 
 which was a constituent of the blood, do not cause an immediate 
 cessation of the functions of the most important organs, if they 
 continue in their action, although in an abnormal condition, con- 
 valescence ensues. In this case, the products of the transformations 
 still existing in the blood, are used for assimilation, and at this 
 period, secretions of a peculiar nature are produced." 
 
 Having submitted this chemical analogy of the reproduction of 
 contagion in the words of the highest living authority on animal 
 chemistry, it only remains to attempt a rationale of the action of 
 the causes of fever, in accordance with its principles, which may 
 be thus stated : — 1st. That the principal character of the blood 
 consists in its component parts being subject to every attraction ; 
 the chemical forces of this fluid, and the vital principle holding each 
 other in such perfect equilibrium, that every disturbance, however 
 trifling, or from whatever cause it may proceed, effects a change in 
 the blood. 
 
 2d. That bodies, the elements of which are in a state of decom- 
 position, or transposition, when produced from the blood, as con- 
 tagions are, will communicate their state to the sound blood, 
 exactly as gluten in a state of decay or putrefaction, (yeast) causes 
 a similar transformation in a solution of sugar and gluten (wort.) 
 
 Assuming then, that the primary action of the febrile poison is 
 upon the blood, there can be but one essential cause of fever, viz., 
 The introduction of the 'poison into that fluid. Its activity, or 
 the occurrence of the peculiar transformations which it has a ten- * 
 dency to excite in the blood, will be determined by the existence of 
 certain accessory or accidental causes, which disturb the equili- 
 brium between the chemical forces in the blood and the vital 
 influence ; either by their action on the blood, causing the increase 
 of compounds subject to those transformations which the poison 
 produces — as depraved diet, bad air, &c. ; or by their action on 
 the nervous system, withdrawing permanently or temporarily more 
 or less of its influence, and so favouring the chemical action of the 
 poison. Such are the depressing effects of cold, fatigue, anxiety, 
 debauchery, disgust, fear, &c. These are usually termed exciting 
 causes, the former predisposing' causes. 
 
 The occurrence of fever— the length of the interval which may 
 elapse between the imbibition of the poison, and the first febrile 
 movement ; in other words, the length of the latent period — the 
 severity of the disease, and the facility with which infection is 
 
HUDSON ON THE POISON OF FEVER. 125 
 
 received and communicated, will depend upon the relative power 
 of the poison, and its combination with one or more of the foregoing 
 predisposing and exciting causes. 
 
 Thus, the continued imbibition of the poison will sometimes, ap- 
 parently without the co-operation of any accessory cause, result in 
 an attack of fever. This, however, is a very rare case, as though 
 deranged health, and particularly disorder of the receiving functions, 
 may exist, the poison is in this case usually eliminated from the 
 blood, unless the balance of forces in that fluid be disturbed by some 
 one or other of the exciting causes. 
 
 The occurrence of the exciting cause may be, or may not be, 
 accompanied by exposure to contagion. In the case of nurses, and 
 the other attendants of the sick, some single exposure being marked 
 by the presence of an exciting cause, it has been supposed that the 
 infection was then and there received into the system, when, in 
 reality, it was before latent, and only rendered active by the cir- 
 cumstances accompanying this particular exposure. .Again, when 
 the occurrence of the exciting cause is not attended with exposure 
 to infection, the fever is often wrongly attributed to ccld, excess at 
 table, mental emotion, &c, the latent presence of the predisposing 
 contagion not being recognised by the patient, and sometimes, as 
 we have seen, being denied by the physician. 
 
 The exciting cause may act, not only by determining the occur- 
 rence of fever, but also by shortening its latent period. 
 
 This is a frequent effect of exposure to infection. "In these 
 cases, the ascertained laws of incubation," says Fergusson, "will 
 so far be set at nought, that a terrified patient will not only fix the 
 precise moment of infection, but will actually sicken prematurely 
 with small-pox, (a latent infection must of course have been pre- 
 viously received,) through the spectacle of the disease in the person 
 of another, or through the disgust (and nothing worse) of an ex- 
 cremental smell, strongly affecting his alarmed imagination, or 
 through the same impression, he may fall down the victim of an 
 an impossible contagion, like that of yellow fever." 
 
 The apparent shortening of the latent period of morbid poisons, 
 seems to occur under these circumstances : — 
 
 1. A strong impression made on the nervous system at the time 
 of exposure. If this be so powerful as to affect seriously the vital 
 principle, the effects of the poison will follow with proportionate 
 rapidity. The poison of ague, usually so long latent, affords a 
 good illustration : — Dr. G. Bird relates, " that being employed in 
 some experiments upon the gas in marshes (near Woolwich,) having 
 suddenly disengaged a quantity of most offensive gas, he was seized 
 with nausea ; and on the day following, with intermittent fever." 
 
 A similar instance, in his own person, is related by Mr. Evans ; 
 and another, in which death followed in forty-eight hours. In this 
 last case, the blood was found fluid. 1 
 
 1 On the Endemical Fevers of the West Indies. 
 
126 HUDSON ON THE POISON OF FEVER. 
 
 2. A less powerful impression upon the nervous system may ac- 
 company exposure, and be followed by a latent period, apparently 
 shortened, but admitting' of the supposition of infection previously 
 latent. Several of Sir H. Marsh's cases afford illustrations of this 
 fact. And it is very probable that exposure to contagion in this 
 way often produces merely the same effect, as an exciting cause, 
 that cold or any depressing agent would exert. 
 
 3. The circumstances accompanying exposure to one kind of 
 poison, instead of acting as accessories to the action of that poison, 
 may cause the immediate action of another, previously latent. 
 
 , This is the only reasonable mode of explaining the cases of ir- 
 regular contagion, related by Marsh and others, of typhus, received 
 from small-pox patients, scarlatina from typhus, ague from typhus, 
 and typhus from puerperal fever. 
 
 Some of these cases we might truly term impossible contagion, 
 unless explained by the supposition of a previously latent poison. 
 The facility of reception of the disease depends upon two conditions ; 
 1st. the presence in the blood of compounds capable of undergoing 
 the transformation of the poison. This constitutes susceptibility; and 
 when it exists in a great degree, and conjoined with, 2d, diminu- 
 tion of the vital influence, it constitutes the highest degree of pre- 
 disposition to disease. The proneness which the living body may 
 thus acquire to infection, may be so great (as seen in crowded col- 
 lections of wretched beings in large cities, deprived of air, light, 
 fuel, clothing, and sustenance,) as to resemble that incapacity of 
 resisting the progress of decay, (a true contagion) which is exhibited 
 by dead animal matter, placed in a putrefying atmosphere. 1 
 
 The severity of disease depends partly on the above circumstances, 
 but principally upon the dose of the poison. This may be illus- 
 trated by comparing small-pox and measles, received in the natural 
 mode, with the same diseases communicated by inoculation. Indi- 
 viduals may suffer as severely from the latter as the former, but the 
 generality of persons do not. The following passage in a recent 
 work of great ability offers inducements to consider this subject 
 somewhat in detail : — "The modifications in disease dependent on 
 the mode of introduction of the morbific cause, is, however, a sub- 
 ject too difficult for me to grapple with, and the observations are 
 too few to offer any precise result. Cruveilhier, in the article 
 i Phelibitis Diet, de Med. et Chir. Prac' points out the increased 
 intensity of effect when pus is introduced into the circulation at 
 once, and as compared with that caused by gradual absorption from 
 an abscess. The modification which small-pox undergoes by 
 inoculation, as compared with that malady acquired by inhalation, 
 is very remarkable." 2 From this last observation it would appear 
 that the author considers the modification of small-pox as not con- 
 
 1 A fact noticed by Parent Duchatelet, in some infectious places in Paris; 
 and by Senac, see Wilson Philip on Fevers, vol. i. page 210. 
 2 Fergusson on Diseases of Women, page 104. 
 
HUDSON ON THE POISON OF FEVER. 127 
 
 sistent with Cruveilhier's observation. Such an idea must have 
 arisen from confounding the matter of the small-pox pustule with 
 the poison of small-pox, 1 when in realify it only contains the poison 
 in common with the blood and all its excretions. 
 
 1 The distinction between them is well staged by a writer in the ' Edinburgh 
 Medical and Surgical Journal,' vol. liii. p. 206. 
 
 "Rayer mentions ' pus and miasm' as two distinct agents which should 
 never be confounded. If the contagious effluvium and the matter of the 
 pustule were one and the same thing, how could we account for the circum- 
 stance of the foRtus in atero becoming affected with the small-pox ? Besides, 
 Dr. Waterhouse and others have recorded cases in which persons exposed 
 only to the exhalations from the blood of small-pox patients have been after- 
 wards attacked by the disease." 
 
 The fact marked in italics would also serve to prove the distinctness of 
 the poison from the ponderable matter of lues. Other considerations would 
 lead us to extend it to all morbid poisons. For 
 
 1. The peculiar action of a morbid poison on the blood presumes its pos- 
 sessing great diffusibility in that fluid ; and this quality is known to exist in 
 all- substances universally, as the cohesion of their atoms, or in oiher words, 
 their ponderability. 
 
 2. The power of permeating tissue depends upon the same condition ; and 
 while we find that all the morbid poisons may act without abrasion of sur- 
 face, we find that those which do appear to permeate the skin, act with more 
 certainty if presented at a temperature which admits of their volatilisation. 
 This is notoriously true of small-pox, as the dissection of subjects who have 
 died of this disease, though not harmless, is much less infectious than the 
 handling of the living body. It is also well known that the examination of 
 any dead body is most likely to be followed by the bad consequences of a 
 dissecting wound, when the body is warm and contains the halitus of its 
 
 cavities uncondensed the next in point of danger being that which 
 
 is next in diffusibility ; the exposure of the surface of the hands to the liquid 
 contents of the serous cavities in particular cases, especially in puerperal 
 peritonitis. 
 
 I need only refer to Mr. Stafford's paper on this subject in the 20th vol. of 
 the u Medico-Chirurgical Transactions" for instances of the imbibition of 
 this poison in puerperal and other cases, without any abrasion of surface. 
 The following circumstance bearing on this subject occurred to myself a 
 short time since. 
 
 I was sent for to see a lady in the latter end of her first pregnancy, who I 
 was informed had been for some time suffering much painful anxiety of mind 
 and fatigue of body, and had been laboriously occupied with the arrange- 
 ments for entering on a new residence, which had kept her constantly upon 
 her feet. For some weeks the legs had swelled considerably, and pitted 
 under pressure. This swelling had rather suddenly increased, and extended 
 to the thighs and pelvic region, with a feeling of stiffness and inability to 
 walk up stairs. Her pulse was quiet, tongue clean, and general health ap- 
 parently perfect. This was on the morning of the 21st of December. All 
 appeared to go on well, and the swelling seemed to diminish a little till the 
 night of the 23d, when she slept none, and was attacked with vomiting. 
 On the morning of the 24th I found her remarkably changed ; the counte- 
 nance haggard and anxious, with a quick irritable pulse, thickly furred tongue, 
 restlessness, and vomiting of a dark green fluid. Labour pains came on at 
 10 a. m. and continued regularly during the day. About 10 p. m. she had 
 an attack of convulsions, and in a few minutes another. Delivery was im- 
 mediately effected by the assistance of the forceps. It was observed that the 
 labia had since morning become very dark coloured, and the perineum tore 
 upon the slightest stretching like wet brown paper, but without bleeding. 
 
128 HUDSON ON THE POISON OF FEVER. 
 
 The poison of small-pox is equally subtle and imponderable with 
 the other morbid poisons, an aura, present it is true in the matter 
 of the pustule, but equally present and equally capable of commu- 
 nicating the disease in the gaseous exhalation which arises from 
 
 The delivery of the child was followed by that of a second, unassisted ; both 
 being quite dead and flaccid. The uterus contracted firmly, and there was 
 no hemorrhage ; but the patient became less and less capable of being 
 roused, the abdomen enormously distended, respiration laborious, and she 
 sunk at 2 a. m. three hours after delivery. 
 
 About four in the evening of that day, I felt a hot painful itching upon the 
 back of my right hand, where I perceived a small transparent vesicle. In a 
 couple of hours I had pain in the axilla, and an uncomfortable, chilly feel. 
 I applied a number of leeches to the hand and took an emetic, followed by 
 calomel and James's powder. These means removed all unpleasant general 
 symptoms, but the part itself did not recover so speedily, as an ill-condition- 
 ed obstinate sore formed on the hand which was long in healing. Not the 
 slightest scratch or puncture existed before the application of the poison. 
 
 But whence this poison ? It was ingeniously suggested to me by ray friend, 
 Dr. Clifford, who assisted me through this most distressing case, that the 
 vital powers being over-taxed for the nutriment of two children, had given 
 way, and this decomposition before death was the consequence. Perhaps 
 this is the only explanation which can be admitted. 
 
 But I am inclined to believe that the whole was the effect of phlebitis, by 
 which a morbid poison was generated, which produced death in the foztuses, 
 disorganisation in the mother, and being presented under circumstances 
 favourable to absorption, rapidly permeated the skin to which it was (only 
 for a few moments) applied. Every thing was favourable to the occurrence 
 of crural phlebitis and to the absorption of the poison into the patient's sys- 
 tem, as will appear from the history of the case, without again enumerating 
 particulars. Dr. Wilson's paper, in the "London Medical Gazette" for 
 April 1838, proves that crural phlebitis in women is not confined to the 
 puerperal state. 
 
 Note. — It was not till after the section upon the Theory of Fever had been 
 sent to press, that I met with Dr. Hodgkin's remarks upon the nature of the 
 fever in his recently published volume on diseases of the mucous membranes, 
 Lecture 23d. "I shall now proceed to state what I have conceived to be 
 the condition of the system which constitutes fever, whether it be produced 
 by the influence of some local inflammation or lesion, or exist by itself, in- 
 dependently of such exciting cause. This latter form, however, if it have 
 an existence, I regard as of much rarer occurrence than has generally been 
 supposed. Fever, I imagine, to depend on the suspension, or at least very 
 considerable interruption of that process by which, during health, the vari- 
 ous parts of the system are continually undergoing a change, the old 
 
 materials being removed, whilst others are substituted in their place 
 
 The process of incessant and universal change of the particles constituting 
 our frames is what we imply by the terms nutrition and ' interstitial absorp- 
 tion,' it is not merely in its character closely allied to secretion, they are, I 
 believe, essentially parts of the same function," &c. This view is supported 
 by strong facts derived from the phenomena of fever, and by much ingenuity 
 of reasoning. And Dr. Hodgkin proves, at least, that such an arrest of the 
 molecular change takes place with reference to the secretions and nutrition 
 of the body in fever. Thus far, there is a coincidence between his theory 
 and that advocated in the foregoing section; the same suspension of secre- 
 tion and accumulation of organic matters in the system, being part of both 
 explanations, and the phenomena of solution or crisis being explained simi- 
 larly in both. 
 
 
HUDSON ON THE POISON OF FEVER. 129 
 
 the blood drawn from a variolous patient. The same is true of 
 measles, which has been propagated over and over again by Home, 
 and others, by inoculation with the blood of the patient, and with 
 the same result, — a milder form of disease. By thus separating the 
 poison from its vehicle, the difficulty of explaining the modification 
 of these diseases by inoculation is got rid of, since, to recur to the 
 simile of Dr. Haygarth, a hundredth part of a pint of yeast will not 
 excite fermentation in a barrel of ale, though a pint will do it; and 
 it must be obvious that a single inspiration in the immediate neigh- 
 bourhood of a small-pox patient may introduce more of the aura 
 into the blood than the directintroduction by inoculation of an atom of 
 matter, in which only a small proportion of the poison can be present. 
 The correctness of this view could be readily tested ; and if it were 
 found that, as in typhus, the amount of exposure had an influence 
 in determining the severity of the attack of small-pox, the explana- 
 tion must be admitted. One fact is strongly presumptive in its 
 favour ; it is the less complete removal of the susceptibility to the 
 disease after inoculation than after natural small-pox. The analogy 
 to the fermenting process is too obvious to need suggestion, and the 
 same remark holds good of fever, short and mild fevers being no- 
 toriously more prone to recurrence than a long and severe form of 
 the disease. 
 
 Sect. Y. — The Characters of the Disease produced by the In- 
 fectious Animal poison of Typhus. — The argument for the fore- 
 going theory of fever, would obviously be much strengthened if it 
 could be made to appear that the phenomena of Typhus are so 
 analogous to those of the other morbid poisons, as to entitle it to a 
 place among "those special contagions, which do not amount to 
 more than five or six, and are all comprehended under that class of 
 which it is the general distinguishing characteristic to occur once 
 only during the life-time of the individual ;" in other words, to be 
 classed with the exanthemata. 
 
 The difference is as to the initiatory movement. While Dr. Hodgkin 
 would consider the factor of the disease to be in all cases a local lesion or 
 inflammation, the theory of a morbid poison supposes it to be a molecular 
 change in the blood caused by the dynamic force of the decomposing parti- 
 cles of the poison, from which arise disturbance of the process of innerva- 
 tion, and of the molecular changes of nutrition, interstitial absorption, and 
 secretion. 
 
 The theory does not assume to determine whether the changes in inner- 
 vation (such as rigor) which mark the commencement of formed fever, are 
 the direct effects of the poison carried through the circulation to the nervous 
 centres, or whether, as Dr. Hodgkin infers, from a conversion of Edwards's 
 proposition, " since cold has the effect of retarding, especially that function 
 by which particles to be rejected from the body are thrown off. a suspension 
 of this process from another cause should be attended with a sensation 
 resembling in a degree those caused by cold.'' This seems rather a doubt- 
 ful conversion of Dr. Edwards's fact. I shall hereafter return to Dr. Hodg- 
 kin's ingenious speculations, merely observing for the present, that while 
 some parts ^(see page 491) support a humoral theory, his theory will by no 
 means explain the phenomena of infection as the humoral theory does. 
 4 — e 4 hudson 
 
130 HUDSON ON THE POISON OF FEVER. 
 
 We find medical writers much divided upon the question whether 
 the petechial eruption of typhus is a primary and essential, or a 
 secondary and accidental character of the disease. We may refer 
 to De Haen, 1 Hoffman, and especially to Bruserin's elaborate argu- 
 ment for the former opinion, and for the consequent classification 
 of typhus among the exanthemata ; and among more recent writers 
 the same view is ably supported by Dr. Copeland and Dr. Peebles, 
 Dr. Roupell, and Dr. Davidson. Dr. Alison seems inclined to 
 adopt it, though his language is reserved and cautious. " Such 
 cases of spotted fever may be said to form the link that connects 
 the order of fevers with that of the contagious exanthemata.'* 2 
 
 If it be found that the analogy is complete in every essential par- 
 ticular, and that the objections which have been urged against the 
 classification of typhus with the exanthemata are founded upon sup- 
 posed discrepancies, which have no real existence, we shall be en- 
 titled to substitute for this cautious approximation, the decided 
 definition of Dr. Peebles: "This contagious febrile eruption is an 
 exanthematous affection, the production of human effluvia where 
 society is placed in circumstances favourable to its developement, 
 and should be considered the effect of a poison sui generis. It 
 arises from a miasm, which generates in the human body an erup- 
 tive fever distinct from all others, as other exanthemata are 
 distinct."* 
 
 The first point of resemblance, and one much insisted on by the 
 older writers, is the primary nature of the eruption. In this par- 
 ticular it differs from the petechias which occur in the advanced 
 stage of many fevers, and cannot be considered essential to them. 
 " The petechias," says' Bruserius, 4 "besides that they break out in 
 all patients, or at any rate in by far the greatest number, as I have 
 already said, likewise appear sooner in particular instances, gene- 
 rally about the fourth day, sometimes even earlier ; but very seldom 
 if ever at all delay breaking out beyond the seventh day, unless 
 they be very anomalous, while the secondary and symptomatic 
 ones appear much seldomer, and in fewer patients, nay, very 
 late," &c. 
 
 Hoffman 5 also describes them as appearing "in nonnullis quarto 
 vel circa septimum diem in dorso potissimum pectore et brachiis- 
 cum vel sine levamine maculae in aliis copiosiores in aliis pauciores 
 coloris varii," &c. Modern observations are consistent with these. 
 Thus Dr. Barker, after taking much pains to prove by a reference 
 to older authors, that this eruption was not peculiar to the Irish 
 epidemic of 1817-18, says, "Prom a comparison of many cases, I 
 would infer that it generally makes its appearance between the fifth 
 and seventh days inclusive of the fever," (fee. 6 
 
 1 Ratio Medendi, vol. ii. chap. 1. 
 
 2 Edinburgh Medical and Surgical Journal, vol. xxviii. 
 
 3 Idem. vol. xlvii. 4 Institutes, vol. iii. 
 6 Medicinse Rationalis. Tom. iv. p. 120. 
 
 6 Dublin Medical Transactions, vol. ii. 
 
 
• HUDSON ON THE POISON OF FEVER. 131 
 
 If we refer to descriptions of the jail or hospital fever, we find 
 Monro enumerating the fourth, fifth, sixth, and seventh as the most 
 frequent days of the measly eruption; and Sir J. Pringle states that 
 he frequently saw them as early as the fourth or fifth day. 1 
 
 Another resemblance is presented in the phenomena attending 
 the progress of the disease; more especially the attenuation which 
 may be observed between the eruption and the affections of mucous 
 membranes. In exanthematous typhus, the same dry harassing 
 couo-h is observed previous to the appearance of the eruption, as in 
 measles. On the coming out of the eruption this subsides, unless 
 a catarrhal complication exists. Again, if the mucous membrane 
 of the bowels be the seat of irritation, and a diarrhoea, (whether the 
 effect of the disease or of medicine exist,) the eruption will fade. 
 This is analogous to what has been observed in scarlatina, 2 and it 
 has been urged as an argument for the free use of purgatives in 
 typhus, that they clear the skin from spots. In the definite nature 
 of its progress, and its disposition to terminate critically and at 
 once, typhus resembles the exanthemata as much as it differs from 
 the intermittent and remittent fevers with which it has been con- 
 fused and compared. Neither does it appear that when once the 
 febrile movement has commenced it can be arrested any more than 
 the action of other morbid poisons. Most of the cases in which 
 this is supposed to have been done, have been merely cases of strong 
 nervous shock from exposure to infection, without evidence of the 
 infection having been imbibed into the system. 
 
 The last resemblance upon which it is necessary to dwell, is the 
 mode of communication. 
 
 The fact of typhus being communicated from one person to an- 
 other, is a powerful argument for classing it among the special con- 
 tagions. An examination (hereafter) of the circumstances which 
 favour infection, will show them to be the same in both, and the 
 time at which they become infectious seems to be the same in 
 both, viz. at and after the period of maturation or crisis. The argu- 
 ment adduced by Dr. Ferriar against the humoral theory, "that 
 neither would a patient, after recovering from a nervous fever, 
 cease to infect others till the whole mass of his fluids were changed," 
 is thus deprived of its weight. 
 
 The histories of patients admitted into our fever hospital, afford 
 frequent illustrations of this fact, as they constantly attribute their 
 infection to some neighbour, or member of their family, who has 
 returned home cured from hospital; and there is at present in the 
 hospital a man who has suffered severely from this cause, having 
 lately lost his wife by a typhous fever which commenced on one of 
 his children, who was hugged and kissed by a man upon his dis- 
 charge from the hospital, after passing through a most severe 
 typhus. 
 
 'Monro on Hospitals, p. 10; and Sir J. Pringle on Diseases of the Army, 
 p. 299. 
 2 By Fothergili and others. 
 
 4* 
 
132 HUDSON ON THE POISON OF FEVER. 
 
 Bat as evidence on a large scale is to be preferred to individual 
 instances, let us take Dr. Perry's very strong and satisfactory testi- 
 mony to the fact with reference to both diseases.' 
 
 Into the fever house in Glasgow are admitted cases of measles, 
 scarlatina, and small-pox, and patients are very frequently sent in 
 labouring under bronchitis, &c. &e. I found by experience, that 
 when the latter class of patients were sent into the convalescent 
 ward, where they necessarily mixed with the others, almost all who 
 had not previously had typhus fever, were either seized with it be- 
 fore leaving the house, or returned soon after labouring under it. 
 The period intervening between the time of their being sent to the 
 convalescent ward and the attack being never less than eight days. 
 Although means were taken to keep those recovering from small- 
 pox, scarlatina, &c, in a separate room from those convalescing 
 from fever, the rooms being adjoining, the non-intercourse was in- 
 complete, and the result was, that these diseases occasionally spread 
 among the typhous convalescents, and the convalescents from small- 
 pox and scarlatina caught typhus." He states that " the result of 
 a trial of the plan of keeping non-febrile cases in the acute wards 
 till able to go to their homes was, that not one so detained ever 
 caught fever in the wards, or returned with it afterwards." Dr. 
 Perry's statement is confirmed by Dr. Stewart, who says, "In fact, 
 scarcely one of the hundreds dismissed from the acute wards ever 
 returned labouring under typhus, though they had remained for a 
 week or ten days in wards sometimes crowded to excess,, while of 
 the few who by mistake went into the convalescent wards, scarcely 
 one escaped the disease, and several died." 2 
 
 Such are some of the most striking analogies between typhus 
 and the class exanthemata; others not less important arise from a 
 consideration of the supposed discrepancies which exist between 
 the laws and phenomena of the two diseases. 
 
 Each writer who has opposed this classification of fever, has 
 urged some objection or other which he considered fatal to it. We 
 shall examine them in detail, and endeavour to show that they be- 
 long to two classes. 1, Those which apply to the exanthemata as 
 well as to typhus; and 2, Those which do not apply to typhus, but 
 to other fevers. 
 
 In both cases the argument from discrepancy must be ill-founded, 
 as in the first the differences become analogies, and in the second, 
 typhus, by being separated from other fevers, becomes more com- 
 pletely identified with the "specific contagions." 
 
 To commence with the latent period of typhus. Its variable 
 length has been urged against the classification. That of the exan- 
 themata appears to be equally so. In scarlatina it may extend 
 from a tew hours to twenty-one days, according to Dr. Williams 
 and Dr. Maton. In measles, from a week to a fortnight; and in 
 small-pox, from five to twenty -three days. 
 
 1 Dublin Medical Journal, vol. x. 
 
 2 Edinburgh Med. and Surg. Journal, No. cxlv. 
 
HUDSON ON THE POISON OF FEVER. 133 
 
 II. The eruption, it is said, is not invariably present. This ob- 
 jection is not as strong as it appears, and since it is admitted that 
 the eruption of typhus has only very lately been attentively exa- 
 mined as a diagnostic character of the disease, we cannot think the 
 question likely to be illustrated by the kind of testimony which 
 some opponents bring to bear upon it. 1 
 
 The answers to this objection are, 1, It is often present, though 
 so indistinct as to escape a superficial examination. " On such oc- 
 casions," says Dr. Barker, 2 " the suffusion of the eyes is a pretty 
 certain indication of its presence." "They sometimes," says Bru- 
 serius, 3 "lurk under the epidemics, scarcely perceptible, and are 
 only seen through it on attentive examination ; nay, they some- 
 times do not appear unless cupping glasses be applied, by which 
 they are called out." 
 
 Similar is the observation made by Sir J. Pringle, 4 and repeated 
 by Dr. Ron pell, upon the arm on which a ligature had been applied 
 for bleeding. 
 
 2. In the returns from which the comparative frequency of ap- 
 pearance of the eruption is deduced, there are two sources of error 
 which have been well exposed by Dr. Davidson. The first is, that 
 they contain a large proportion of cases not typhus; the other, that 
 many of them entered hospital at an advanced stage of the disease, 
 after the retrocession of the eruption. 
 
 Dr. Davidson observes that one fact powerfully supports the 
 opinion that contagious typhus, in the great majority of cases, par- 
 ticularly in adults, is attended with the eruption, viz. that almost 
 all the instances of fever which have occurred during the last six 
 or seven years among the physicians, clerks, nurses, &c, of the 
 Glasgow Fever Hospital, have been accompanied with this exan- 
 thema. 5 
 
 The following remarks of Dr. Stewart on this subject deserve 
 consideration. 
 
 " Nor can I consent without reserve to conclusions drawn from 
 the alleged absence of eruption; for the fact I have already referred 
 to (viz. that the eruption in typhus in Edinburgh was unheeded 
 before 1832) shows how appearances may escape the eye of the 
 most distinguished and practised physicians, when their attention 
 is not 'particularly drawn to them. It is also well known to many, 
 that previous to a visit which Dr. Peebles made to the Glasgow 
 Fever Hospital, in the spring of 1835, the exanthema of typhus, 
 then found to be of general occurrence, had neither been looked for 
 nor registered in that institution, and was received as a new dis- 
 covery." 6 
 
 1 Vide Dr. West's paper. 
 
 2 Dublin Medical Transactions, vol. ii. Monro also remarks, that though 
 many had no petechia, in all who were very bad, the countenance looked 
 bloated, and the eyes reddish and somewhat inflamed, page 12. 
 
 3 Institutes. 4 Page 300. 5 Essay. 
 6 Edinburgh Med. and Surg. Journal, vol. liv. 
 
134 
 
 HUDSON ON THE POISON OF FEVER. 
 
 3. We reply that the occasional absence of the eruption is in truth 
 an analogy. "For," says Burserius, "as the variolous fever, or the 
 variolous disease unaccompanied with small-pox, sometimes occurs, 
 I should not consider it at all absurd to suppose that the petechial 
 fever may in like manner take place without petechiae."' 
 
 In another place this author remarks : " This is generally ob- 
 served to happen when they prevail epidemically. But it does not 
 occur so frequently and decidedly to the observation of any one as 
 that of the inoculators. For not unfrequently at the usual time 
 after the inoculation, a fever comes on which continues several 
 days, and then goes off without being followed by an eruption of 
 pustules. Who would not call it a variolous fever ?' n 
 
 I am acquainted with a family in which small-pox made its ap- 
 pearance, affecting different individuals in the following modes. 
 One with confluent eruption, another with scanty, two with vario- 
 lous fever without eruption, and another with intense vomiting and 
 delirium, but no subsequent fever or eruption. 
 
 The same occurrence of a peculiar fever without eruption, has 
 been remarked in epidemics of measles, by Sydenham and others. 
 Rayer states that Guersent has observed individuals in families 
 where measles prevailed, exhibiting all the other symptoms of the 
 disease except the eruption, and that he has himself several times 
 seen cases in which the eruption was incomplete, and which might 
 have been referred to the morbillary fever of Sydenham. 2 
 
 Every one who has had any experience of epidemics of scarlatina, 
 must have observed fever and sore throats of the same character as 
 that of scarlatiria, but without eruption, occurring in families in 
 which this disease prevailed. Rayer quotes the testimony of a 
 number of authors upon the subject, and Dr. Tweedie introduces 
 it as a variety of the disease into his classification, This scarlatina 
 sine exanthemate is very frequently met with in practice. 
 
 III. A want of uniformity of the character and time of appearance 
 of the eruption has been alleged. 
 
 "Of the varying characters of the eruption," says Dr. West, 3 
 "almost every quotation has afforded an illustration, and we have 
 seen the date of its appearance vary from the second to the seven- 
 teenth day." 
 
 We are by no means convinced that the subject has been illus- 
 trated by Dr. West's quotations, which appear to be descriptive not 
 so much of typhus as of every other variety of fever. On the other 
 hand, testimony is not wanting of observers who have explained 
 these apparent irregularities in the character and periods of the 
 typhus eruption, and reconciled their apparent inconsistency with 
 an exanthematous theory of fever. 
 
 Such we meet in the following passages from Burserius's admir- 
 
 1 Institutes, vol. iii. 2 On Diseases of the Skin. 
 
 3 On Exanthematous Fever. Edinburgh Medical and Surgical Journal, 
 No. cxliii. 
 
1 HUDSON ON THE POISON OF FEVER. 135 
 
 able chapter on the petechial fever. " Le Roy also observes that 
 there is some distinction between the primary and secondary pete- 
 chias, which consists in the difference of their colour, namely, that 
 the former are of a palish red and rosy colour, and in general break 
 out in great numbers, principally on the loins and legs ; that the 
 latter, on the contrary, are generally of a purple colour, like deep 
 red wine, and are sometimes also brown or black, and fewer in 
 number." 
 
 But we must also remember that the primary ones break out soon, 
 and when they are epidemic, appear not only in all affected with 
 the same disease, but are likewise very frequently combined with 
 other diseases called intercurrent ones — (for these last are not 
 always wanting, as some contend) — while on the other hand, the 
 secondary ones break out later, and generally about the height, or 
 towards the end of the disease, and not in all patients, but only in 
 those whose blood is so vitiated as to become almost putrid, and 
 occasion gangrenes here and there on the skin, or being thrown 
 into violent commotion by a heating regimen and medicines, is 
 effused into the spaces of the skin, but not by the wisdom of nature 
 endeavouring 1 to free herself from the noxious miasma. Hence I 
 would say that the primary differ from the secondary petechias, 
 because the former arise from a peculiar and poisonous miasma, 
 and the secondary from the crasis of the blood being deranged by 
 the violence of the disease, or from its increased motion, or lastly^ 
 from a heating regimen having been employed." Such also we 
 meet in Dr. Staberoh's paper on the eruption attending epidemic 
 fever. In which he shows that not only do petechias of the ecchy- 
 inotic or secondary kind occur after and apart from the exanthema, 
 but that spots of these are capable of being converted into ecchy- 
 motic spots. 1 Attentive observation has convinced me that not only 
 are the above statements correct, but that we may add that a third 
 variety of late petechias occur in cases in which, from diarrhoea or 
 hypercatharsis, in the beginning of fever the exanthema lurked 
 under the epidemics. The conversion of this indistinct eruption 
 into ecchymosis taking place, or the latter being superadded in the 
 course of the disease, and appearing to be primary. A fourth 
 variety is thus alluded to by Dr. Peebles: "Petechias may be 
 mixed with the exanthema, and in some epidemics the exanthema 
 has been prevented from showing itself by the disease passing so 
 rapidly from the sthenic state to the putrid, that it has not had time 
 to make its appearance." 
 
 Of course under any of the foregoing circumstances the late ap- 
 pearance of a petechial eruption is no argument, for a want of uni- 
 formity in that of the exanthema. The frequency of occurrence 
 of these secondary petechias is only an additional reason for believ- 
 ing that the two forms have been by many writers confounded 
 together. 
 
 1 London Medical Gazette, vol. i. N. S. p. 973. 
 
136 HUDSON ON THE POISON OF FEVER, 
 
 IV. It is objected " That the disease often occurred more than 
 once during the lifetime of an individual." 
 
 The objection assumes that typhus confers no immunity from 
 subsequent attacks, and that the exanthemata do confer an immu- 
 nity. The answer is, that experience warrants our belief in a con- 
 siderable power of destroying the liability to subsequent attacks in 
 typhus, and that, though there can be no doubt of the exanthemata 
 possessing this power, exceptions to it are frequent in all of them. 
 
 It must be admitted that in this country there is a general belief 
 in the protecting power of a seasoning or initiatory fever, and 
 though we rarely meet with -a medical man who has not had typhus, 
 we certainly meet with few indeed who have had it more than once. 
 The nature of the subject does not admit of very precise proof. 
 We can only obtain the general results of experience. Dr. Barker 1 
 states as the results of his, "that he has for some time entertained 
 the opinion that sufferers from fever attended with this eruption, if 
 they are not altogether secured by it from a second attack, are not 
 at least so liable lo it as those who have had a fever of the ordinary 
 kind ; and, though he frequently made the inquiry, he never found 
 a patient, in whom this symptom was distinct who had suffered 
 from the same fever on any former occasion." Dr. Perry 2 states, as 
 the result of an extensive series of observations, his opinion, "that 
 typhus generally is taken but once in a lifetime, and that a second 
 attack does not occur more frequently than of small-pox, and less 
 frequently than of measles or scarlatina." Dr. Davidson states that 
 of 609 patients in the Glasgow Fever Hospital only seventy-four 
 stated that they had ever had fever previously. He justly observes 
 that when we take into account the various diseases which are 
 confounded with typhus, this small number can be easily accounted 
 for. 
 
 But the protective power of the exanthemata has been much 
 overrated. Three instances of second attacks of small-pox came 
 to my knowledge in this county very recently. In two of them 
 the patients had suffered the disease from inoculation very few 
 years before. In one in which the inoculated disease was severe, , 
 a most confluent eruption accompanied the second attack seven 
 years after. Another instance has been related to me of a lady 
 living in this country who has had the disease three times. ^ Dr. 
 Roupell refers to the case of one who had it seven times. 
 
 Instances of second attacks of measles are given by Dr. Bailie, 
 who attended five children in May, and again in the following 
 November; by Dr. Webster, 3 and by Rayer, who states that he met 
 with three instances of second attacks of measles in the interval 
 between the publication of the first and second editions of his work. 
 The remarkable case of a second attack by Dr. Graves 4 should, 
 
 1 Dublin Medical Transactions, vol. ii. 
 ' 2 Dublin Med. Journ. vol. x. and Edin. Med. and Surg. Journ.. Jan. 1836. 
 8 Medico-Chirurgical Transactions. Second Series, vol. iv. 
 4 Dublin Medical Journal, Nov. 1840. 
 
HUDSON ON THE POISON OF FEVER. 137 
 
 perhaps, be termed relapse into measles. The second eruption ap- 
 peared twenty-one daysiifter the commencement of the first illness, 
 in which the eruption had been copious and severe. 
 
 Cases of second attack of scarlatina are stated by Roupell to be 
 not at all uncommon. Several have fallen under my own obser- 
 vation. 
 
 V. The liability to relapse in cases of typhus has been urged as 
 an objection to the classification by Harty and others. It might be 
 replied that cases of measles, such as that of Dr. Graves just re- 
 ferred to, and cases of reversio, as it is termed by Rayer, after scar- 
 latina, would tend to show that the exanthemata are not exempt 
 from relapse. But the true answer is that typhus is peculiarly ex- 
 empt from relapse. Two kinds of cases are erroneously considered 
 such: 1st. Relapses from typhus into fever symptomatic of a vis- 
 ceral irritation — generally gastro enterite. — " I am persuaded, says 
 Cheyne. 1 " that obstinate and fatal relapses after typhoid fevers are 
 often attributable to inflammation and, perhaps, ulceration of the 
 villous coat of the intestines." And Broussais asserts that " when 
 the frequency of pulse in ' convalescence' does not diminish, and 
 the strength does not increase, it may be suspected that a form of 
 latent inflammation exists. It may be discovered by permitting an 
 excess which generally changes this frequency into a real fever, 
 and developes the pain of the irritated part;" 2 but, 2dly, cases of 
 fevers not typhoid will under exposure to infection relapse into 
 typhus. Dr. Davidson gives a tabular view of the relapses in the 
 Glasgow Fever Hospital among 686 cases, in which no case of 
 relapse from typhus into typhus occurred, but two of febricula and 
 one of intestinal fever into typhus. 
 
 In 500 cases of fever admitted into the Navan Hospital in 1840, 
 two cases only of relapse into typhus occurred, both were cases of 
 febricula, which after a few days were sent to the convalescent 
 ward, where they relapsed into maculated typhus, one in four days 
 and the other in fourteen davs after their removal thither. 
 
 VI. Lastly, the following extraordinary objection is put forward 
 by Dr. West :— 3 
 
 " The type of the fever itself varies, being sometimes intermit- 
 tent, sometimes continued, changing from the one to the other 
 form, and being occasionally converted into other diseases." 
 
 In other words there is no such disease as typhus ! 
 
 To this the supporter of the speciality of typhus replies, that the 
 disease is here, and in numerous quotations throughout the paper, 
 confounded with other fevers ; typhoid it may be in their nature, 
 or becoming so in their progress, not arising from an animal in- 
 fectious poison, but from a variety of sources, which contain a 
 variety of poisons, the identity of any one ofivhich with the typhus 
 
 i 1 Dublin Hospital Reports, vol. i. 
 
 2 Chronic Phlegmasia, vol. ii. p. 53. 
 
 3 On Exanthernatous Typhus. 
 
138 HUDSON ON THE POISON OF FEVER. 
 
 poison is a matter in dispute, and to be argued upon the conclusion 
 of our investigation into these sources in the following chapter. 
 
 Meantime the pertinent remarks of Dr. Copland, upon this sub- 
 ject, are not unworthy the notice of those who rely for the means 
 of drawing accurate distinctions upon such sources as Dr. West 
 has explored :— " True or contagions typhus has been confounded 
 with synochoid and nervous fevers on the one hand, and with 
 putrid or malignant fevers on the other. It has been already stated 
 that putridity or malignancy, not only may characterise a parti- 
 cular form of fever or certain epidemics even at an early period of 
 their course, but also, owing to various contingencies, may take 
 place in advanced stages of any other fever. As the circumstances 
 favouring the generation and spread of typhus are often such as 
 also tend to develope those changes which have been usually named 
 putrid or malignant, and as these changes are frequently observed 
 in the latter stages of typhus — the symptoms distinguishing this 
 fever becoming associated with, or followed by, those indicating 
 the putro-adynamic state — so has it been often confounded with 
 other fevers in which this state has predominated more or less. If 
 we refer to the numerous histories of epidemic typhus, recorded by 
 writers from the close of the fifteenth century up to the present 
 time, we shall find that although many of these, owing to the con- 
 currence of circumstances developing a putrid or malignant dis- 
 ease, were instances of fever either identical with or very closely 
 resembling that which I have described as such in the preceding 
 section, yet many others, or even the majority, were true typhus, 
 in which the putro-adynamic state was either early or predomi- 
 nantly developed. The exanthematous eruption, characteristic of 
 typhus, being succeeded or accompanied by the petechia?, indicat- 
 ing the approach of the septic condition, and being either, mistaken 
 for them or for an eruption of miliaria. Owing to this circumstance, 
 especially typhus, low, nervous, and putrid fevers, have been very 
 generally confounded together." 
 
 The reader of the foregoing, and many other passages in Dr. 
 Copland's admirable article on typhus, must be startled with the 
 following passage in Dr. Roupell's recent work on the disease, 
 when he finds that Dr. Copland is not like Peebles and others, 
 who have described exanthematous typhus, passed over in silence, 
 but is actually mentioned by name as belonging to the authors re- 
 ferred to. 
 
 " In the above description typhus is considered to belong to the 
 continued fevers. It is looked upon by the most recent authors, in 
 this and other countries, not as an individual disorder, but as one 
 into which others may be and frequently are converted ?" (page 5.) 
 
 Here for the present we leave the subject, since that portion of 
 the argument for the classification of typhus with the exanthemata, 
 which is derived from the differences between it and other con- 
 tinued fevers, will properly come under consideration when dis- 
 cussing the identity of typhus and typhoid fever. 
 
HUDSON ON THE POISON OF FEVER. 139 
 
 CHAPTER II. 
 
 Of a Fever Poison, generated during the Decomposition of Dead Organic Matters. 
 
 The difficulties attending an examination into this part of the 
 inquiry into the sources of fever are very great, and are confessed 
 by all who are familiar with the conflicting statements advanced 
 on the subject. Our difficulties are increased by the indeterminate 
 character of much of the evidence offered in proof of the paludal 
 origin of fever, some of which not only claims to prove the power 
 of such sources to cause continued, but infectious fever — by the 
 fact that much of this evidence is moreover inadequate, as it proves 
 only the occurrence of fever in situations and among persons which 
 might be considered equally obnoxious to contagion as to miasm, 
 and by the silence, or mysterious, or contradictory language of 
 those to whom we might look for assistance and direction in a 
 scrutiny of the mass of conflicting testimony, from which our con- 
 clusions are to be drawn. 
 
 Thus, Dr. Christison says, " the great questions involved in the 
 investigations into the causes of continued fever are three in num- 
 ber : — Does the disease originate in infection ? Does it originate in 
 other causes ? Granting that it does originate in other causes, may 
 such fevers propagate themselves by infection ? It will be seen that 
 they cannot be all answered by any means with equal confidence ;" 
 and, accordingly, while he is full and illustrative on the subject of 
 contagion, he treats of other causes in a most cursory and unsatis- 
 factory manner, and while he admits that " the general conclusion 
 from the whole facts seems to be that a disease, undistinguishable 
 from true infectious fever, may sometimes arise without infection," 
 adds, '-that on descending from the general question to the more 
 special one — what the other cause or causes of fever may be ? — the 
 difficulties are greatly increased, indeed they become insurmount- 
 able, without such limited and vague facts as are at present pos- 
 sessed on the subject," and " it appears a needless waste of time 
 and labour to attempt any thing further on this head." 
 
 Nor are we more enlightened by Dr. Davidson, who, while he 
 states that he is not prepared to assert that febrile affections may 
 not, under peculiar circumstances (what he does not inform us,) 
 arise from paludal sources, effectually excludes them from con- 
 sideration by putting forward the following conclusions under the 
 head of " Alleged sources of continued fevers, not typhoid/' 
 
 "From a consideration of the whole evidence that might be ad- 
 duced respecting this point, it may be drawn as a conclusion, that 
 although putrid matters when injected into the veins of animals 
 cause death under symptoms similar to those of typhus fever, yet 
 that the effluvia arising from similar matters do not, under ordinary 
 circumstances, produce any deleterious effects on man." Again — • 
 
140 HUDSON ON THE POISON OF FEVER. 
 
 " Before concluding this part of the essay we shall notice an hypo- 
 thesis, which has lately been somewhat confidently brought for- 
 ward to account for the prevalence of typhus in some large cities, 
 viz. : that a peculiar malaria is generated by the animal and vege- 
 table filth, which accumulates along the sides of rivers running 
 through large towns, and that the inhabitants who live in their im- 
 mediate vicinity become thereby subject to fever. We are quite 
 aware that very disagreeable and sometimes fetid effluvia occa- 
 sionally arise from such situations, particularly during hot weather, 
 but that it is capable of causing continued fever has not even been 
 rendered probable by any satisfactory evidence.*' 
 
 We have it stated upon high authority that gaseous contagions 
 contain organic matter in a state of decomposition or progressive 
 change. We have it also announced that from certain decomposing 
 animal and vegetable substances, organic matter in a state of "pro- 
 gress to decay" is evolved, which, when collected and retained in a 
 manner similar to the former, completes the stage of decomposition, 
 or, in other words, "putrefies." 
 
 By evidence of the most unexceptionable kind the former of these 
 is proved to be capable of communicating the state of change, of 
 which it is the subject, to the healthy human organism. 
 
 We have to inquire whether the analogy of action of these bodies 
 is as perfect as the analogy of condition appears to be, and, whe- 
 ther, "when the process of respiration is modified by contact with 
 a matter in the progress to decay, when 'this matter communicates 
 the decomposition, of which it is the subject, to the blood — disease 
 is produced." 
 
 - We shall first state the analogy of condition of the tangible poi- 
 son, evolved from decomposing organic substances, in the words of 
 Dr. Southwood Smith — not only because it is clearly stated by 
 him (so far as relates to its tangible existence,) but, also, because 
 this passage has furnished the text for some of the objections which 
 we shall have to consider 1 : — "It is known to every one that the 
 putrefaction of vegetable and animal matter produces a poison, 
 which is capable of exerting an injurious action on the human 
 body. But the extent to which this poison is generated, the con- 
 ditions favourable to its production, and the range of its noxious 
 agency, are not sufficiently understood and appreciated. It, is a 
 matter of experience, that during the decomposition of dead organic 
 substances — whether vegetable or animal — aided by heat and 
 moisture, and other peculiarities of climate, a poison is generated, 
 which, when in a state of high concentration, is capable of produc- 
 ing instantaneous death toy a single inspiration of air in which it is 
 diffused. Experience also shows that this poison even when it is 
 largely diluted by an admixture with atmospheric air, and when, 
 consequently, it is unable to prove thus suddenly fatal, is still the 
 fruitful source of sickness and mortality — partly in proportion to 
 
 1 Poor-law Commissioners' Fourth Report, page 130. 
 
HUDSON ON THE POISON OF FEVER. 141 
 
 its intensity, and partly in proportion to the length of time, and the 
 constancy with which the body remains exposed to it, &c. 
 
 " But this poison was too subtle to be reduced to a tangible form. 
 Even its existence was ascertainable only by its mortal influence 
 on the human body; and although the induction commonly made 
 as to its origin, namely, that it is the product of putrefying vegetable 
 and animal matter, appeared inevitable, seeing that its virulence is 
 always in proportion to the quantity of vegetable and animal mat- 
 ters present, and to the perfect combination of the circumstances 
 favourable to their decomposition, still the opinion could only be 
 regarded as an inference. But modern science has recently suc- 
 ceeded in making a most important step in the elucidation of this 
 subject. It has now been demonstrated by direct experiment, that 
 in certain situations, in which the air is loaded with poisonous ex- 
 halations, the poisonous matter consists of vegetable and animal 
 substances in a high state of putrescency. If a quantity of air in 
 which such exhalations are present be collected, the vapour may 
 be condensed by cold and other agents, a residuum is obtained, 
 which, on examination, is found to be composed of vegetable or 
 animal matter in a high state of putrefaction. This matter consti- 
 tutes a deadly poison. A minute quantity of this poison applied to 
 an animal, previously in sound health, destroys life with the most 
 intense symptoms of malignant fever. If, for example, ten or 
 twelve drops of a fluid, containing this highly putrid matter, be in- 
 jected into the jugular vein of a dog, the animal is seized with 
 acute fever, the action of the heart is inordinately excited, the re- 
 spiration becomes accelerated, the heat increased, the prostration 
 of strength extreme, the muscular power so exhausted that the 
 animal lies on the ground wholly unable to stir or to make the 
 slightest effort, and after a short time it is actually seized with the 
 black vomit, identical in the nature of the matter evacuated with 
 that which is thrown up by a person labouring under yellow fever. 
 By varying the intensity and the dose of the poison thus obtained 
 it is possible to produce fever of almost any type, endowed with 
 almost any degree of mortal power." 
 
 In this last sentence we recognise the echo of Magendie's ques- 
 tionable assertions; the preceding statements are confirmed by the 
 account of experiments upon " le mau vais air," given by Devergie i 1 
 "The gas, which is disengaged from putrefying animal matters, 
 extracts with it a particular odour, infectious ' infecte,' characterised 
 by the general term putrid odour. We attribute this odour to 
 miasma, that is to say to a cause void of meaning, because we are 
 ignorant of the nature of the object which it represents. 
 
 " Guntz has endeavoured to enlighten the phenomenon by the 
 following experiment: he placed a bell glass over a portion of a 
 putrefying dead body, in such a manner as to permit the air to 
 
 1 Medicine Legale. Tom. i. p. 100. .1 am indebted to my friend Dr. 
 Aldridge for referring me to this account of experiments on the subject. 
 
142 HUDSON ON THE POISON OF FEVER. 
 
 penetrate, he submitted the apparatus to a temperature of 26° Cent, 
 (equivalent to about 78° Far.) and, after a period sufficiently pro- 
 longed, he suddenly cooled the bell glass; immediately the product 
 of the vapour assembled itself into drops, which evolved a strong 
 odour of miasma, he treated these drops with chlorine, when the 
 odour disappeared. He was thus led to suppose that the gas in 
 escaping from the putrefying animal matter carried with it the 
 vapour of water combined with a certain quantity of animal matter, 
 very minutely divided, and this constitutes what has been named 
 miasma. 
 
 " This is not the only experiment calculated to lead to this opin- 
 ion — others have been made with respect to vegetable matters. 
 Moscati entertained the first idea of condensing the water dissolved 
 in the atmosphere, for the purpose of detecting the principle which 
 occasioned ' le mauvais air.' He suspended at some distance from 
 the soil mattrasses full of ice; the water which became deposited 
 upon their surfaces condensed itself readily, when limpid it present- 
 ed many small flakes which possessed all the essential properties 
 of animalised matter. After a few days they putrefied completely. 
 In the course of the year 1812, M. Rigaud undertook, in the marshes 
 of Languedoc, a series of essays directed to the same end. He 
 condensed dew on glasses, and the water which he obtained by 
 this means presented all the phenomena obtained by Moscati. 
 
 "In 1819 M. Boussingault observed that sulphuric acid placed 
 in the proximity of a well, in which he had caused animal matter to 
 putrefy, blackened very rapidly. He repeated this experiment in 
 many infectious places, and found constantly that the coloration of 
 the acid was more prompt according as the air was more infec- 
 tious," &c. 
 
 The inference naturally deduced from such experiments as the 
 foregoing, taken in conjunction with the fact of the occurrence of 
 fever in situations where these putrid exhalations have been found 
 to exist — namely, that they contain a fever poison — has been met 
 by numerous objections. The principal seem to be the following : 
 
 1. That a mephitic poison is confounded with the fever poison. 
 
 2. It is denied that these sources ever generate fever, because the 
 number of cases does not bear a sufficient proportion to the number 
 of instances of exposure, and because they generate several diseases 
 differing in their nature from fever, and it would amount to a con- 
 founding of fever with these, 1 if we attributed its origin to the same 
 poison. 3. It has been objected to the evidence of the frequent 
 occurrence of fever from this source — that it is furnished from the 
 experience of persons who deny the infectiousness of fever, and is, 
 
 1 " Dr. Smith illustrates and supports his doctrine of the malarial origin 
 of fever by referring to facts which relate merely to periodic fevers ; and he 
 maintains the identity of the 'fever poison' of this country with the poison 
 of plague ; wherefore, on the principle, that things that are equal to the same 
 thing are equal to one another — plague and ague are generated by the same 
 poison !" — Forbes ] s Review, No. 21, p. 13. 
 
HUDSON ON THE POISON OF FEVER. 143 
 
 therefore, suspicious ;* that in the recorded cases malaria and con- 
 tagion have been confounded ; that it amounts only to a proof of 
 the frequent coincidence of fever and the effluvia from filth, and 
 does not prove that the former stands to the latter in the relation of 
 an effect to a cause ; that, granting continued fever is ever thus 
 produced, it is not contagious or typhus fever, &c. 
 
 I. It has been said 2 — " If the statements of Dr. Smith were put 
 into the simple form of the only proposition which they really con- 
 tain, they would amount merely to this — that exhalations from 
 certain putrescent matters have the power of producing both 
 asphyxia and continued or typhus fever ; the former of which is a 
 result familiar to all, and the latter, a mere assertion, deriving a 
 little hue of probability from its juxtaposition to a known truth. 
 There is a wide difference between the asphyxia, which is caused 
 by mephitic gases, and typhus fever, — a difference which can never 
 be explained, as Dr. Smith attempts to do, by a reference to the 
 diversity in the doses of the poison. We presume that if a few 
 doses of the poison, in its less potent shape, were sufficient to create 
 typhus fever, « fortiori, such a quantity of it in a more concen- 
 trated form, as would be capable of producing a state of asphyxia 
 not ultimately fatal, would commonly at least leave the sufferer 
 for days or weeks in the toils of a highly dangerous fever, yet the 
 reverse is the case, as the histories of mephitism amply demon- 
 strate." 
 
 So they doubtless do, and they, moreover, show that in some 
 cases of recovery from mephitism, a disease, apparently the effect of 
 a morbid poison, followed, though not fever. 
 
 But this writer has, like Dr. Smith, confounded the action of two 
 poisons of different kinds — an inorganic poison, sulphuretted 
 hydrogen, and a morbid poison, whose action depends not upon its 
 chemical qualities, but upon the existing condition of its particles, 
 they being at the time of their evolution in a state of decomposition 
 or transposition. 
 
 The advocate for the malarial origin of fever does not regard the 
 fever poison as the product of extreme putrefaction, capable of 
 causing mephitism or fever, according to the dose in which it is 
 applied. But he holds that during the progress to decay of organic 
 substances, matter in a slate of decomposition is evolved which is 
 capable of communicating its state to the organism with which it 
 maybe brought into contact, while, on the completion of the process 
 of decomposition, the morbid poison ceases to be evolved and the 
 mephitic poison is generated. 
 
 A perfect analogy to this is found in the effects of decayed sau- 
 sages, which, according to Christison, "are poisonous only at a 
 particular stage of decay, and cease to be so when putrefaction has 
 advanced so far that sulphuretted hydrogen (the mephitic gas) is 
 
 1 Vide Dr. Christison's article — Fever. Library of Medicine. 
 a Forbes's Review, ut supra. 
 
144 HUDSON ON THE POISON OF FEVER. 
 
 evolved." True, in mixed sources, and those which are receiving 
 daily additions of new matters, the morbid poison may co-exist 
 with the mephitic poison, and the latter may occasionally, by its 
 sedative effects upon the nervous system, assist the operation of the 
 former ; but they are essentially different in their nature and action. 
 
 The second objection — "an alleged want of proof that the fever 
 poison is ever generated in such sources" — rests, 1st, upon the re- 
 latively small number of cases of fever so produced, compared with 
 the activity of contagion ; and, 2dly, upon the fact that several 
 diseases of different kinds, from tic-doloureux up to plague, are at- 
 tributed to miasmic effluvia. Can we (it is asked) believe that they 
 are all owing to the same poison? 
 
 The first of these grounds is urged against decomposing animal 
 matters ; the second chiefly against mixed sources, as sewers, banks 
 of rivers, &c. 
 
 It is true that very few observations exist which can be said to 
 prove the occurrence of fever from exposure to animal putrefaction — 
 still, some such cases have occurred. The following is referred to 
 by Dr. Christison as an unexceptionable one : — ? 
 
 " An American merchant-ship was lying at anchor in Whampoa 
 road, sixteen miles from Canton. One of her crew died of dysentery. 
 He was taken on shore to be buried ; no disease of any kind had 
 occurred in the ship from her departure from America till her 
 arrival in the river Tigris. Four men accompanied the corpse and 
 two of them began to dig a grave. Unfortunately they lit upon a 
 spot where a human body had been buried about two or three 
 months previously, as was afterwards ascertained, — the instant the 
 spade went through the lid of the coffin a most dreadful effluvium 
 issued forth and the two men fell down nearly lifeless: it was with 
 the greatest difficulty their companions could approach near enough 
 to drag them from the spot and fill up the place with earth. The 
 two men now recovered a little, and, with assistance, reached the 
 
 boat and returned on board One of these men died on the 
 
 evening of the fourth day, and the other on the morning of the fifth, 
 after symptoms of malignant petechial fever (the petechias occurring 
 on the fourth day.) 
 
 "In eight days after the opening of the grave one of those who 
 were not engaged in the work was attacked with the same symp- 
 toms as his companions, and the fourth had a slight indisposition 
 of no very decided character." 
 
 It is to be remarked, that in the above case two circumstances 
 were present which we shall see have not always existed in the 
 negative instances, brought forward to prove that this is not a 
 source of fever; namely, "confinement of the effluvia," and a not 
 very advanced stage of putrefaction. Ferriar, who did not con- 
 sider the exhalations from putrid animal matters a source of fever, 
 
 • 
 
 1 Medico-Chirurgical Review, for Jan. 1825, p. 203. Dr. Christison also 
 refers to the Meoi. de la Soc. Royale de Med. 1. 97. 
 
HUDSON ON THE POISON OP FEVER. 145 
 
 says — la It appears from some late observations made on altering 
 the vaults of a church in France, that the confined effluvia of putrid 
 bodies produce fever when brought into action. Perhaps this is 
 the solution of the question." 2 " Fourcroy states, that the grave- 
 diggers informed him that the putrid process disengages elastic 
 fluid, which inflates the abdomen and at last bursts it ; that this 
 event instantly causes vertigo, faintness and nausea in such persons 
 as, unfortunately, are within a certain distance of the spot where it 
 happens, &c." In the exhumations, conducted on such a large 
 scale at the cemetery of the Innocents, and quoted by Bancroft and 
 others in proof of his position, neither of these conditions could 
 have existed, since no interments had been allowed for six years 
 previously. 
 
 In many of the cases also related by Mr. Walker it is mentioned 
 that the bodies had been buried for years, or were in an advanced 
 stage of putrefaction ; under these circumstances mephitism was 
 produced — but not fever. 
 
 The other part of this objection, namely that so many different 
 diseases are ascribed to this source — can they all be the effect of 
 the same poison ? can only be answered by supposing a variety of 
 morbid poisons to be formed together or consecutively in the same 
 source. Several considerations render it probable that this is the 
 case in some malarial sources. 
 
 1. The progressive nature of the changes which the decompos- 
 ing body undergoes, and the different circumstances under which 
 the same organic matters (undergoing decomposition) may be placed 
 in different places, or at different times. There is nothing impro- 
 bable in the supposition, that the same source may at one time give 
 origin to. the poison of ague, and at another to the poison of fever. 
 
 2. The fact that an individual exposed to these sources will fre- 
 quently become affected with two diseases. These will usually 
 follow one another at a short interval. " In the vast horde of 
 cases," says Dr. Addison, 3 " which the river side is continually 
 sending forth, synochus and typhus are of frequent occurrence, and 
 these are frequently followed, when the patient is convalescent, by 
 well-defined agues." Sir H. Marsh has noticed the same occurrence 
 in the epidemic of 1826, in Dublin, and it is well known that after 
 this epidemic the hospitals of that city were filled with cases of 
 ague. This is perfectly analogous to what happens from exposure 
 to two morbid poisons, the one which has the shortest latent period 
 takes precedence and is followed by the other, as in the case related 
 by Dr. Williams of a boy who was inoculated at the same time 
 with the virus of measles and cow-pock. The cow-pock, first ran 
 its course, and was then followed by measles. In the same way it 
 is very possible that the poison of ague, imbibed at an early part of 
 
 1 Medical Histories, vol. i. On New Contagions. 
 
 2 Walker's gatherings from Grave-yards, p. 124. 
 
 8 On Malaria. London Medical Gazette, — vol. iii. new series. 
 
 4 — f 5 hudson 
 
146 HUDSON ON THE POISON OF FEVER. 
 
 the year, may lie latent until the conclusion of a continued fever 
 received many weeks later. 
 
 3. This power of generating different diseases, is alleged of those 
 sources in particular which contain a variety of organic matters, 
 and which are in a state of constant change from the superaddition 
 of new materials or from atmospheric changes — such are sewers, 
 the banks of rivers, &c. — and it is to these that the great body of 
 evidence, as to the frequent production of fever, applies, and not 
 to the regular, uniform, and spontaneous decomposition of any 
 * single portion of animal matter, however great its bulk. 1 
 
 Sect. II. — In order to obviate the objections urged against the 
 evidence of the frequent occurrence of fever from malarial sources, — 
 namely, that it has been cqnfounded with contagion, and that, at 
 all events, the evidence proves no more than the frequent co-exist- 
 ence of filth, fever, and poverty. 
 
 We shall select only a few cases which have occurred under cir- 
 cumstances unfavourable to the supposition of such a cause as 
 contagion, and the histories of which present contrasts to that of 
 contagious fever in some of the following particulars. 
 
 I. The class of persons affected, not those usually obnoxious to 
 contagious fever unless under circumstances of prolonged exposure. 
 
 II. Occurring without the presence of any of the aids to contagion 
 and at an opposite season of the year. 
 
 III. In localities in which contagious fever does not prevail. 
 
 IV. Spreading in spite of the preventive measures, which are 
 found to check the diffusion of contagious fever. 
 
 " In great towns," says Christison, "cases are met with during 
 the intervals between epidemics, and in a station of life where 
 epidemic fever in epidemic seasons of the worst kind is seldom 
 witnessed. A fever of this description, tedious in its course, charac- 
 terised by much nervous and muscular depression, without any 
 particular local disturbance, and, especially, without the marked 
 
 1 If the subject admitted of an explanation purely hypothetical we might 
 draw an analogy, not destitute of plausibility, between the action of human 
 contagion and putrefaction in this particular; and we might suppose, that as 
 in fever generated spontaneously in the human body, there does not seem to 
 exist any power of communication by infection, so in dead animal matter 
 the product of any single mass of spontaneous putrefaction is not a fever 
 poison, but that this is' generated by the exposure of fresh dead organic mat- 
 ter to the contagion of the former. For this hypothesis tobeponsistent with 
 the facts, the following should be the various consequences of exposure to 
 putrefactive decomposition : — 
 
 1. From exposure to a single mass of animal matter undergoing spontane- 
 ous putrefaction — no fever. 
 
 2. From exposure, to the emanations from substances added to the former 
 disease, varying in intensity in proportion as circumstances were more or 
 less favourable to rapid communication of the "contagion of decay" from 
 decomposing to recent organic matter. 
 
 3. From successive exposure of a number of individuals to successive ad- 
 ditions of organic matter, (under above circumstances,) a number of cases 
 of disease. 
 
HUDSON ON THE POISON OP FEVER. 147 
 
 disorder of the functions of the brain which distinguishes most 
 cases of epidemic typhus and synochus. was so prevalent among 
 the better ranks in certain streets of Edinburgh some years ago, at 
 a time when fever was not prevalent among the working classes, 
 that a general impression arose among professional people of the 
 existence of some unusual local miasma. A great variety of parallel 
 facts might be referred to — all leading to the general conclusion, 
 that a disease if not identical with, at all events closely resembling, 
 synochus and typhus as described above, may arise without the 
 possibility of tracing it to communication with the sick. A state- 
 ment of this kind acquires great weight in the instance of such a 
 visitation of disease as that just alluded to, which prevailed among 
 people in easy circumstances in a great town." 
 
 Very similar is the testimony of Dr. Cheyne : — "For several 
 years the fever appeared in families only in solitary instances, or if 
 more than one were affected they were seized nearly at the same 
 time, but it did not extend so as to lead us to think that it propa- 
 gated itself. We were unable to assign the cause of the disease 
 further than that we observed in several houses, in which our 
 patients lay, that fetor which is discoverable when a sewer is 
 choked, and, in some instances, upon enquiry it was found that the 
 sewer leading from the house had been improperly constructed and 
 neglected." 
 
 A similar instance of fever, apparently caused by defective 
 sewerage, came under my observation recently in the house of a 
 gentleman of fortune in this county. For a longtime an unpleasant 
 odour had been remarked in several parts of the mansion, more 
 especially near this gentleman's study and in the men servants' 
 sleeping apartment. The poisonous effects of the malaria were first 
 produced in the form of obstinate dysentery in one of the female 
 servants. Then the owner of the mansion was attacked with what 
 he at first supposed was mere biliary derangement, but which 
 rapidly assumed all the characters of severe gastric fever, becoming 
 attended towards the close with purple petechias and terminating 
 fatally on the 11th day. 
 
 About the same time two men servants were seized with symp- 
 toms of fever. In one it was cut short and in the other it ran its 
 course, ending favourably about the 11th day. 
 
 Two other persons who came to the house on business (from the 
 neighbourhood) and who remained in it for a few hours, were 
 seized with the same fever, which ran through its course at their 
 own houses but without extending to other individuals. 
 
 After this lamented occurrence the cause of the effluvium was 
 searched for and found to be a leakage of the soil pipe of one of 
 the water-closets, which had allowed the filth to percolate through 
 the wall and exhale into the atmosphere of the house. This exha- 
 lation was also much favoured by the warm temperature kept up 
 in the house by heated flues. 
 
 About the months of October and November, 1839. 1 was repeat- 
 
 5* 
 
148 HUDSON ON THE POISON OP FEVER. 
 
 edly consulted by the inmates of a large establishment in the 
 neighbourhood of Navan, on account of different forms of gastro- 
 enteric affection, especially diarrhoea and dysentery. So many 
 instances occurred at intervals, (in some cases of weeks,) and the 
 general resemblance was so great, that I thought they must arise 
 from some local cause, and I expressed a strong suspicion that some 
 source of malaria existed in the house or immediate vicinity. The 
 house itself was large, airy, and commodious, so that our inspection 
 was directed rather to the immediate neighbourhood, and it was 
 thought that the cause had been discovered in an old sewer which 
 had been laid open in the course of some building operations. The 
 closing of this was not, however, attended with the effect of stop- 
 ping the endemic affection, though it gradually ceased after about 
 a dozen people had been attacked. The following spring was re- 
 markably dry, scarcely any rain having fallen for about six weeks; 
 toward the close of this period an effluvium of a very disagreeable 
 nature became perceptible in some parts of the house, and at the 
 same time — within a day of each other — two of the inmates were 
 attacked with exquisitely marked typhus, attended with profuse 
 measly eruption, and in one of the patients with violent delirium. 
 Every circumstance rendered the existence of contagion in either 
 case highly improbable, I might almost say impossible, and on my 
 again expressing my strong conviction that some form of malaria 
 was the cause of the fever, I was informed of the effluvium per- 
 ceived in some of the passages, and also of the fact that in the 
 original construction of the water-closets they had been made to 
 depend for their supply of water upon a cistern of rain water, which, 
 of course, had been for weeks empty during the present spring and 
 preceding autumn. These cases did not spread; and all traces of 
 indisposition were removed by making the required alterations for 
 ensuring a constant supply of water. 
 
 In the month of October, 1839, 1 attended a respectable man who 
 resided in a large and airy mansion, as "care taker," during the 
 absence of the family upon the Continent. His illness had come 
 on slowly and insidiously, but, when I saw him, had all the cha- 
 racters of bad remittent fever, attended with much abdominal con- 
 gestion. This it was attempted to relieve by leeches, &c. but it 
 increased and led afterwards to large evacuations of blood from the 
 bowels. He recovered slowly and with difficulty. At the time I 
 saw him he was lying in the basement story of the house. 
 
 A few weeks after the return home of the family, the butler was 
 attacked with symptoms of gastro-enterite and slight jaundice. He 
 recovered partially in a few days, but in the course of a week after 
 was suddenly seized with complete loss of muscular power, paleness 
 and coldness of the surface, sickness of stomach, &c, followed by 
 vomiting of a dark olive fluid, and in two days by large evacuations 
 of tarry blood from the bowels, hiccup, subsultus, &c, while the 
 skin was covered with vibices and black petechia? — some of them 
 of the size of large shot. The fever which followed had no percep- 
 
HUDSON ON THE POISON OF FEVER. 149 
 
 tible remissions and perfectly accorded with the descriptions of 
 putrid malignant fever by Huxham and others. The striking 
 resemblance of some of the symptoms of this case to that which had 
 occurred in the same place more than a year before, led me to at- 
 tribute both to a common cause and to enquire for the source of the 
 malaria. The following were the facts ascertained : — In a room in 
 the basement story, occupied by the last patient and in which he 
 had latterly sometimes slept, was a sink emptying into a pipe, 
 which communicated at the distance of about ten feet with the main 
 sewer of the house — into which the contents of two water-closets 
 passed. This sewer was very large at its termination and when 
 the wind blew from that direction towards the house, there being 
 no smell trap under the sink, the effluvium of the sewer was carried 
 up into this room and became so insupportable that the patient used 
 to stuff the aperture with a piece of rag when retiring to bed. 
 Upon inquiry I was informed that the first patient had frequently 
 before his illness remarked the same fetid effluvium. It is worthy 
 of remark that the sewer had not been cleaned in the interval be- 
 tween the two cases. 
 
 The following case, very similar to the last in its nature and 
 origin, I give upon the suspicious authority of ananticontagionist: 1 
 " I attended," says Dr. Armstrong, 2 " a very respectable tradesman, 
 labouring under a remarkable bad attack of typhus fever. It was 
 such a case as would have been called plague in the time of Syden- 
 ham. He had knotted glands and carbuncles, and black petechia?. 
 He was one of four or five individuals who had transacted some 
 business in a nobleman's kitchen ; a filthy fluid had overflowed that 
 kitchen ; he was sickened at the time, and in common with all 
 the others had an attack of typhus fever." 
 
 If we looked about for a large town less liable to contagious fever 
 than others we mi^ht probably find it in Birmingham, — yet here 
 endemial causes, of the kind which Dr. Davidson has pronounced 
 inadequate to this effect, have produced fever. A good instance 
 for illustration is found in Dr. Ward's account of an endemic fever, 
 which prevailed in certain localities in Birmingham in the summer 
 of 1837. 
 
 3 " The river Rea, that separates Birmingham from its suburb 
 Badesley and serves as a cloaca maxima to both, carries its filthy 
 stream onward, partly to turn a mill and partly to fill a mill pond. 
 During the drought which prevailed last year the water was very 
 low in the main stream and mill pond, and the mills not being 
 regularly worked became quite stagnant and offensive. The back 
 stream also became dry and showed its mud banks, that were only 
 occasionally wetted by a flush of the washings of the town after a 
 shower, or by the small surplus accumulated during the cessation 
 
 1 See Christison, ut supra. 
 
 8 Lectures by Rix. 
 
 % Provincial Medical Transactions, vol. 6. 
 
150 HUDSON ON THE POISON OF FEVER. 
 
 of the working of the mills. The exhalations from the half dried 
 mud and putrid water were so disagreeable at night as to nauseate 
 the more delicate inhabitants of the adjoining streets, and soon pro- 
 duce disease in the form of typhoid fever of an infectious (?) charac- 
 ter." He goes on to state that about 50 cases — some fatal — occurred 
 in the immediate vicinity of the stream, and " still lower down the 
 stream, where the water was as black as ink, there were 13 pauper 
 cases in one yardr, and many others, both pauper and private, along 
 the same line." That this fever was owing to the state of the stream 
 is proved by the disease being confined to the locality, the small 
 number affected in so large a population as Birmingham, the sea- 
 son of the year, and the exemption of this town from the causes 
 which aid contagion — these are well summed up by Dr. Ward. 
 
 " There is a difference of nearly 200 feet in the elevation of dif- 
 ferent parts of the town. The streets and the courts or yards in 
 which the mechanics live are wide and airy in general ; fuel is 
 cheaper than in any other large town in England ; the water is 
 excellent — and till within the last year there has been but little 
 distress." 
 
 We have already adduced the effects of seclusion of the sick in 
 proof of the infectiousness of typhus. In the fever arising 1 from 
 endemial sources this measure has no such influence. I was much 
 struck with this fact when making some investigations as to the 
 source of a fever, which prevailed in the summer of 1839 in a ham- 
 let attached to a flax manufactory near this town, from which a 
 considerable number of cases had been sent to hospital in the 
 months of April, May, and June. The object of an examination 
 which I made of the place was to obtain satisfactory instances of 
 contagion, but I soon found that no such evidence was to be pro- 
 cured. For the intervals between the illness of different members 
 of the families were too irregular to admit of communication from 
 one to-another. Thus, in one house the first case sickened on the 
 2d of April, and the second on the 5th. In another, more than 
 three months intervened between the first and second cases. And 
 in several families in which the first case had been early removed 
 to hospital, the second had sickened before the patient's return. 
 Besides, there was too much cleanliness and comfort : several of 
 the houses had been repeatedly white-washed during the time that 
 the fever was going through the family, and the inmates were all 
 well off — being employed in the neighbouring factory. 
 
 Several things convinced me that this fever had a malarial origin. 
 The hamlet was built in the form of two parallel streets, terminat- 
 ing in a large open space, in front of which were twelve houses 
 looking northeast. This space had no drainage and was full of 
 shallow pools of black putrescent water, into which the inmates 
 daily threw cabbage leaves, <fcc, to rot for manure. In this country 
 the east and northeast winds prevail for the first three months 
 of summer — April to June — and in consequence the inhabitants of 
 the twelve houses described were peculiarly obnoxious to the ema- 
 
HUDSON ON THE POISON OF FEVER. 151 
 
 nations from these pools. The weather had during the summer 
 been unusually dry and favourable to such emanations. Accord- 
 ingly I found that while only seven cases of fever had occurred in 
 twenty-two houses, forming the longer of the two streets, 30 out of 
 50 (the entire number) had occurred in these twelve houses. 
 
 The proof was to my mind rendered complete by the immediate 
 effect of the heavy rains which set in in July. The disease was 
 stopped at once, and I have not heard of a case of fever in the same 
 place since. 
 
 Similar proof, derived from the sanatory effect of the removal of 
 the assigned cause, was afforded me in the case of a house in this 
 county from which three servants were sent into the Navan hospital 
 at short intervals labouring under continued fever, one of whom 
 was also admitted a second time with severe dysentery. A very 
 offensive smell had been long noticed in the yard adjoining the 
 kitchen, and after the occurrence of these cases the sewer leading 
 from the kitchen was in consequence examined, and found to be 
 completely obstructed by a quantity of black putrescent matter. 
 Upon the removal of this the smell of course disappeared, and no 
 return of indisposition has since occurred, either among the servants 
 or family. There was not the slightest evidence of contagion in 
 any of these cases. 
 
 A reason for attributing the fever to the operation of endemial 
 causes might be found in some instances, in the fact of the great 
 indisposition of the disease to spread in the house in which a case 
 occurs, even though the circumstances favourable to contagion may 
 be present. Such an instance is given by Dr. Fergnsson which 
 we shall have again to notice. 
 
 In a paper on the statistics of fever, in Belfast, Dr. Mateer states 
 that " one street, Carrick's Hill, and its continuation, Mill-field, with 
 the adjoining lanes and entries, are found to have furnished three 
 fifths of the whole amount of cases, and yet they are by no.means 
 the poorest or worst ventilated parts of the town." He attributes 
 the prevalence of fever in this locality to the great want of water — 
 "the consequences of which are want of cleanliness and bad sewer- 
 age, so that decayed animal and vegetable matter of all kinds, not 
 being carried off by a current of water in the usual way, accumulate 
 and generate miasmata." 1 This observation is of the more value 
 that Dr. Mateer adduces it in support, of the action of infection. 
 Upon which an acute reviewer remarks : — " Surely this offers the 
 very strongest argument against Dr. Mateer's own view of the ex- 
 tensive operation of contagion ; why should this be all powerful in 
 one particular locality? why should it not do its worst where 
 poverty and bad ventilation flourish ? why, but that on the large 
 scale other causes of fever are far more potent than contagion.' 
 
 1 Dublin Medical Journal, September, 1836. 
 * Medico-Chirurgical Review, Oct. 1836. 
 
 >:2 
 
152 HUDSON ON THE POISON OF FEVER. 
 
 Lastly, the following case by Dr. Currie illustrates this form of 
 fever in several particulars : — 
 
 " The 30th regiment, as is usual with troops in Liverpool, was 
 billetfed in the town but paraded and mounted guard in the fort, 
 siluated north of the town and on the banks of the river. The 
 general guard room had been used, previous to the arrival of the 
 30th, as a place of confinement for deserters; it was extremely 
 close and dirty, and under it was a cellar, which in the winter had 
 been full of water. This water was now half evaporated and 
 from the surface issued offensive exhalations. 
 
 " In a dark, narrow, and unventilated cell off the guard room it 
 was usual to confine such men as were sent to the guard for mis- 
 behaviour, and about the beginning of June, 1792, several men 
 had been shut up in this place on account of drunkenness, and suf- 
 fered to remain there twnty-four hours under the debility that suc- 
 ceeds intoxication. The typhus or jail fever made its appearance 
 in two of these men about the first of the month, and spread with 
 great rapidity. Ten of the soldiers labouring under this epidemic 
 
 were received into the Liverpool Infirmary The symptoms 
 
 of the fever were very uniform, in every case there was more or 
 less cough with mucous expectoration ; in all those who had sus- 
 tained the disease eight days and upwards there were petechia? on 
 the skin, in several there were occasional bleedings from the nose 
 and streaks of blood in the expectoration. The debility was con- 
 siderable from the first Great pain in the head with stupor 
 
 pervaded the whole, and in several instances there occurred a con- 
 siderable degree of low delirium Our next care was to stop 
 
 the progress of the infection ; with this view the guard house was 
 at first attempted to be purified by washing and ventilation; the 
 greatest part of its furniture having been burnt or thrown into the 
 sea. All our precautions and exertions of this kind were, however, 
 found to be ineffectual. The weather was at this time wet, and 
 extremely cold for the season ; the men on guard could not be pre- 
 vailed on to remain in the open air, and, from passing the night in 
 the infected guard room, several of the privates of the successive 
 reliefs on the 10th, 11th, and 12th of the month, caught the infec- 
 tion No means having been found effectual for the purifica- 
 tion of the guard room it was shut up, and a temporary shed erected 
 in its stead. Still the contagion proceeded on the morning of the 
 13th, three more having been added to the list of the infected. On 
 that day, therefore, the whole regiment was drawn up at my re- 
 quest, and the men examined in their ranks : seventeen were found 
 with symptoms of fever upon them. It was not difficult to distin- 
 guish them as they stood by their fellows. Their countenances 
 were languid, their whole appearance dejected, and the admata of 
 their eyes had a dull red suffusion. These men were carefully 
 separated from the rest of the corps and immediately subjected to 
 the cold affusion These means were successful in arresting 
 
HUDSON ON THE POISON OF FEVER. 153 
 
 the epidemic — after the 13th of June no person was attacked 
 by it." 
 
 It may seem presumptuous to offer an opinion differing from 
 that expressed by the distinguished writer under whose observa- 
 tion these cases occurred, but we think there is every reason to 
 question the existence of infection, and to regard them as of purely 
 endemial origin. Let us consider them with reference to the cir- 
 cumstances unfavourable to the existence of contagion before enu- 
 merated. 
 
 1. The class of persons affected. — British soldiers in time of 
 peace are not obnoxious to contagious fever. The fact is stated 
 by Dr. Cheyne, that while fever of this kind prevailed in the street 
 contiguous to the principal barrack in Dublin, in 1817, and among 
 a class of persons with whom the soldiers commonly associate, they 
 escaped, because " little under the influence of the predisposing 
 causes of fever ; for the pay of the soldier is ample, he is well 
 clothed, well fed, well lodged, and well looked after, and all his 
 wants in health as well as in sickness are provided for." 1 
 
 2. The season of its occurrence is another strong reason for con- 
 sidering this fever of an endemial kind. A contagious epidemic 
 may live out the summer, but unless it is imported we should doubt 
 its being generated at that season. 
 
 3. The locality was also unfavourable. Isolated as it was, an 
 imported contagion was unlikely. 
 
 4. The inefficacy of all the preventive measures, short of re- 
 moval from the locality, with the immediate cessation of the disease 
 which followed this step, are strongly opposed to the idea of infec- 
 tion. In fact if it be admitted that the stage of maturation or crisis 
 is the period of infection, an examination of the dates of these cases 
 will show that in no one was the disease so far advanced as to have 
 enabled the patient to communicate it to his comrades, supposing 
 them (which is not at all probable) to have had access to the hos- 
 pital. On the other hand the positive evidence in favour of ma- 
 laria is clear and decisive. Several individuals were exposed to 
 this source during the debility which succeeds intoxication, and 
 slept in its immediate neighbourhood. They were attacked, and 
 others in succession as they became exposed to the same source. 
 The malarious spot is abandoned on the 12th, and no case is ob- 
 served after the 13th. Hereafter we shall attempt to show that the 
 symptoms of these cases were such as characterise not typhus but 
 typhoid fever — especially the late appearance of petechias, the exu- 
 dations of blood from the air-passages, and the form of disturbance 
 of the sensorial functions. 
 
 The above are a few of the instances which might be brought 
 forward to prove the occurrence of fever in situations and circum- 
 stances unfavourable to contagion, and not liable to the objection 
 that filth has existed merely in fortuitous connection with fever and 
 
 1 Dublin Hospital Reports, vol. ii. 
 
154 ' HUDSON ON THE POISON OF FEVER. 
 
 •poverty. It would not be difficult to draw from the published his- 
 tories of infectious fever (so called) such a number of similar facts, 
 as would render doubtful the justice of Christison's objection, that 
 "as for the few instances remaining, where true primary fever ap- 
 pears to originate in one of the above causes, all that need be said 
 farther is that for one instance where such fever follows such cause, 
 a thousand instances occur where no effect of the kind ensues, and 
 that, consequently, some more essential influence is probably brought 
 into play, than what appears merely on the surface of the investi- 
 gation." But some argue that the disease produced is not fever — 
 for, first, it does not diffuse itself as fever does by infection. This 
 is not the place to enter upon an examination of the conflicting 
 statements upon this question — we shall do so hereafter ; but ad- 
 mitting that it has been asserted too hastily by Dr. S. Smith, and 
 others, that infectious fever is generated by paludal sources, we 
 deny that this justifies the inference sought to be deduced, that, 
 therefore, continued fever is not so generated. On the contrary, it 
 seems more consonant with reason to infer, that if fever affects a 
 number of individuals in a certain locality without appearing to be 
 communicated from one individual to another, and without, in any 
 instance, being carried from that locality, this fever must arise from 
 some local source common to all the affected persons. And if that 
 party are in extreme, who hold that fever of a contagious specific 
 character is daily generated by common causes external to the 
 human body, equally so are the opposite party who deny to these 
 sources the power to cause fever, " not typhoid," while at the same 
 time they are ready to admit the identity of their own " specific 
 contagion" with a disease which, the most eminent observers main- 
 tain, is never contagious ! It is surely more consistent with the 
 doctrine of the speciality of typhus to let it stand alone, and to give 
 a place to non-contagious continued fever, than to exclude the lat- 
 ter by a doubtful assimilation of typhus and typhoid fevers. Here- 
 after we shall attempt to show that the most recent science is in 
 accordance with the practical observation of Grant, that " these 
 fevers, ' typhus,' are generally contagious, which the common fevers 
 are not, unless their nature is altered, and they are rendered malig- 
 nant by bad treatment'' — while we may see reason in the present 
 state of society in our large cities, in the widely prevailing influ- 
 ence of crowding, poverty, non-ventilation, &c. and the conse- 
 quently frequent and facile transition of common into contagious 
 fever, why the most opposite conclusions are formed as to their 
 origin and diffusion, and why it happens, as Christison truly re- 
 marks, that "the greater proportion of the discrepant doctrines of 
 the present day as to the origin of fever are founded essentially 
 upon the same great body of facts." 
 
 Again, by some it is urged that the disease produced by paludal 
 emanations differs from continued fever in symptoms and in type. 
 Thus Dr. Christison alleges that " few inquirers have taken suffi- 
 cient pains to distinguish primary continued fever from irritative 
 
HUDSON ON THE POISON OF FEVER. 155 
 
 gastric fever." This objection cannot be allowed to have much 
 weight so long as the primary nature of typhoid fever is a matter 
 of dispute. Upon the subject of the type Dr. Christison may be 
 quoted against his party, for if, as he asserts, " The coast remittent 
 fever of Africa and other tropical countries seems to differ little in 
 its characters from synochus, with a rapid and early stage of ty- 
 phoid depression," 1 what becomes of the argument against the ma- 
 larial origin of continued fevers from alleged differences in the 
 nature of these and the intermittent and remittent fevers, also pro- 
 duced by malaria? Besides how can the exclusive contagionist 
 answer the anti-contaHonist who rests his doctrine on such facts 
 as those adduced by Armstrong: "Shortly after I had published 
 my third edition on typhus fever, in which I had strenuously main- 
 tained the doctrine of human contagion, I met with a case of inter- 
 mittent fever ; in a few days the fever became remittent, and in a 
 few days more put on the continued character, and the patient died 
 with all the most malignant symptoms ?" 2 or how will he dispose 
 of the assertion of Dr. Elliotson, that most cases of so called typhus 
 fever are really remittent, 3 or explain the occurrence (already no- 
 ticed) described by Marsh and Addison of well-defined ague, fol- 
 lowing on the subsidence of continued typhus or synochus ? Was 
 the ague also the effect of contagion ? Or will the contagionist 
 escape from the necessity of adopting so easy a solution of the diffi- 
 culty as the supposition of different morbid poisons, generated at 
 different periods in the same locality, by a simple denialof the fact, 
 and an impeachment of the accuracy of the observers who have 
 recorded: it? " In Sydenham's time," says Dr. Hancock, "and even 
 in that of Pothergill, thequotidian of spring became continued fever 
 in summer, while the simple continued fever of summer often 
 changed to a malignant type in autumn. These were simple ob- 
 servations at a time when systematic arrangements had not put 
 physicians in trammels. But now lest we should be guilty of medi- 
 cal heresy we must not insinuate that ague can change into con- 
 
 1 Library of Medicine. 
 
 2 Lectures by Rix. 
 
 3 Lectures by Rogers. Dr. Mateer also observes — ".We have the par- 
 oxysms of which fever is made up best seen in the intermittent and remit- 
 tent fevers, but still by careful observation we can detect something of the 
 same kind, though masked and often difficult to recognise, in the continued 
 fevers of this country. These almost always assume more or less of the re- 
 mittent character." — Dublin Journal, ut supra. 
 
 Dr. Currie remarks, whoever has watched the progress of fever must have 
 observed the justness of the observations made by Cullen, Vogel, De Haen, 
 and others, that even those genera which are denominated continued are 
 not strictly such, but have pretty regular and distinct exacerbations and re- 
 missions in each diurnal period — Med. Reports, p. 16. 
 
 And Dr. Fordyce says, the similarity between these three kinds has de- 
 termined practitioners of the greatest eminence, through the whole history 
 of medicine, to consider them as the same disease. Many have thought 
 that in a continued fever the subsequent paroxysm takes place in the hot fit 
 of the prior paroxysm, &c. — {Third Dissertation, p. 59.) 
 
156 HUDSON ON THE POISON OF FEVER. 
 
 tinued fever, and non-contagious fever into contagious typhus, 
 either in an individual case or in the course of the year." 
 
 Sect. III. — Varieties of the Sources and Modes of Application 
 of the Poison. — The organic matter constituting the source of the 
 morbid poison may be purely animal, vegetable, or a mixture of 
 both. 
 
 It must be admitted that fever seems to be very rarely produced 
 by exposure to purely animal exhalations, and the facts brought 
 forward by Bancroft, Chisholm, Duchatelet, and others, show that 
 in the great majority of cases this exposure has been continued for 
 any length of time with perfect impunity, but still there have oc- 
 curred well authenticated instances to the contrary, some of which 
 have been referred to ; and a fact lately published, by M. Devergie, 
 deserves farther notice. It is the occurrence of hospital gangrene 
 in the hospital of St. Louis, which he attributes to the emanations 
 from Montfaucon, since the disease was confined to the wards 
 which were exposed to those emanations, and did not appear in 
 other parts of the building. 
 
 1 Now if we admit the inference which seems naturally to follow 
 from such instances as those related by Pringle, Hennen, (fee, of 
 the occurrence of typhus in the un wounded, in wards in which 
 hospital gangrene existed, and of typhus attacking the attendants 
 employed in washing the bandages' of the same — namely, that hos- 
 pital gangrene is a modification, or as it has been expressed, "a 
 visible personification" of the typhus poison ; we cannot avoid the 
 admission that a fever poison may be generated by decomposing" 
 animal matter under certain conditions. 
 
 What the conditions required for this result may be, and why it 
 so seldom-happens that fever is thus produced, are questions to be 
 resolved by deeper and more accurate investigations than appear 
 yet to have been made. 
 
 There seems to be a more general belief in the activity of the 
 vegetable poison, though why it might be difficult to say, unless 
 from juxtaposition with the known fact of their power to cause 
 periodic fevers, since there is at least an equal paucity of strict evi- 
 dence with regard to this as to the animal source. About fifteen 
 years since I witnessed the origin of a highly typhoid petechial 
 fever in a healthy village in England, which appeared to arise from 
 a vegetable source, a heap of putrefying turnips. In a house close 
 to the nuisance, a boy had for two or three weeks been complain- 
 ing of headache, lassitude, and debility, but had not been placed 
 under any medical care. On the day on which I saw him he had 
 been attacked with epistaxis which continued till his death, on the 
 day following. His skin was covered with small ecchymotic pete- 
 chias. After his death petechial fever appeared in the family, con- 
 sisting of six persons, and in the adjoining houses, and proved fatal 
 in several instances. It did not spread beyond the locality, and 
 subsided in a few weeks. The season of the year (summer,) with 
 
HUDSON ON THE POISON OF FEVER. 157 
 
 the other circumstances 3 were unfavourable to the supposition of 
 contagion. 
 
 But it is to sources containing mixed organic matters that the 
 experience of all observers point as most efficient in producing con- 
 tinued fever; such are slaughterhouses, obstructed sewers, cess- 
 pools, &c. <fec. It were needless to add to the details already given 
 of cases originating: in these sources. 
 
 The modes in which the poison may be applied to the organism 
 are by direct introduction into the circulation, by being taken into 
 the stomach, by inhalation, and by the skin. 
 
 Fever, or a disease confessedly bearing a close resemblance to it, 
 has been produced in the lower animals by experiments too well 
 known to need us to dwell upon them, and occasionally the typhoid 
 symptoms which appear in other diseases would seem to be owing 
 to the absorption of putrid matters into the circulation. A case of 
 the kind once occurred under my own observation : a boy aged 
 ten years was received into hospital, labouring apparently under 
 typhoid fever ; he sunk after a few days, and on dissection the only 
 lesion discoverable was a carious state of the petrous bone, with a 
 minute opening communicating with the lateral sinus, through 
 which the matter of the carious abscess had passed into the circu- 
 lation. 
 
 It is but rarely that an instance occurs of fever produced by 
 putrid matters taken into the stomach, and the immunity enjoyed 
 by savages, who live much upon putrid flesh, &c, has been referred 
 to by Bancroft and others, not only against the fact, but also against 
 the supposition of putrid animal matters containing a fever poison. 
 It is not difficult to understand that this should be the case, since 
 digestion, an antiseptic process, precedes assimilation, and changes 
 remarkably the matters submitted to its operation ; or, as accurately 
 expressed by Liebig, putrid poisons having an alkaline reaction are 
 rendered inert by the acids contained in the stomach, while these 
 exert no such power over poisonous sausages which have an acid 
 reaction. But this rule is not without some exceptions. In Dr. 
 Christison's work on poisons is a report of a case which occurred 
 in Stockport in the year 1830, of a family of five persons who were 
 poisoned with broth made of putrid beef; in three instances the 
 disease produced was severe, and in one fatal. It is worthy of re- 
 mark (and is in accordance with the mode of action of a morbid 
 'poison) that in the worst cases the illness did not commence till the 
 second (and in the fatal case the third) day after the meal. A case 
 is somewhere narrated of a regiment in which putrid fever prevailed, 
 and in which the disease was checked upon a discovery being made 
 that the water used for drinking was drawn from a well in which 
 some bodies were lying in a state of putrefaction. 
 
 Dr. Copland 1 remarks upon the effects of drinking the water of 
 the Seine at Paris, and Dr. Hancock observes, that it has been fre- 
 
 1 Dictionary of Practical Medicine, art. Endemic Influences. 
 
158 HUDSON ON THE POISON OF FEVER. 
 
 quently remarked that this water produces diarrhoea in every one 
 except the Parisian accustomed to the use of it. 1 Dr. Tweedie 
 refers to the history of a fever ascribed to the combined effect of 
 drinking putrid water and the emanations from the same — and 
 others ascribe the putrid fevers of Paris to the fact that " there are 
 numerous wells in that city from which many of the inhabitants 
 derive their whole supply of water, not a few of which are situated 
 in the very neighbourhood where the 'fosses' are the worst con- 
 structed and the least attended to ; the urine, therefore, permeating 
 the soil must necessarily contaminate the springs from which these 
 wells are fed." 2 
 
 The evidence given before the committee on the health of towns, 
 by Mr. J. B. Wood, bears upon this question. After stating (qs. 
 2150-4) that 31,000 persons live in the cellars of Liverpool — form- 
 ing two thirds of the working population — he states that, "in the 
 districts in which these cellars are situated, there is a great deal of 
 broken ground in which there are pits ; the water accumulates in 
 these pits, and of course at the fall of the year there is a good deal 
 of water in them, in which there have been thrown dead dogs and 
 cats and a great many offensive articles. This water is neverthe- 
 less used for culinary purposes. I could not believe this at first, 
 I thought it was only used for washing, but I found it was used by 
 the poorer inhabitants for culinary purposes." 
 
 The change produced in the fluids and solids of an animal by 
 over driving seems to be capable of becoming a cause of disease in 
 the human body. In the remarkable case given by Andral from 
 Du Hamel it does not appear that fever, strickly speaking, was pro- 
 duced. The effect rather resembled hospital gangrene ; but an in- 
 stance is recorded of typhus fever following from eating the flesh of 
 animals under similar circumstances. It is thus quoted by Dr. 
 Gross: 3 " A few years ago a number of fattened cattle were driven 
 into one of the New England cities, and having been pressed too 
 hard in a sultry day were so overheated that some of them became 
 quite exhausted. In this condition they were slaughtered, and the 
 consequence was, as is stated by the reporter of the case, Dr. Foun- 
 tain, that nearly all who partook of their flesh were seized with 
 typhous fever." 
 
 These and similar observations would seem to show that the 
 morbid poison, the product of putrefactive decomposition, may be 
 received into the system through the stomach, more especially if 
 presented in the fluid form ; but there is every reason to conclude 
 that fever is but seldom produced in this way, and that the general 
 mode of introduction is through the respiration of the gaseous ex- 
 halations, which, as we have seen, are found upon their being col- 
 lected and condensed to contain animalised matter in the state of 
 
 1 Cyclopaedia of Practical Medicine, art. Endemic Diseases. 
 
 2 Medico-Chirurg. Review, vol. vi. 
 
 3 Pathological Anatomy, vol. i. p. 223. 
 
HUDSON ON THE POISON OF FEVER. 159 
 
 progress to decay, whose power of producing* disease, in those 
 exposed to their influence, has been questioned and is by many 
 denied, but appears to be proved by evidence of a very satisfactory 
 nature, and which applies with most force to cases occurring under 
 circumstances unfavourable to the action of contagion. 
 
 Sect. IV. — On the Mode of Action of the Poison. — This does 
 not appear to be attributable to its chemical qualities, but to its 
 condition. It is the power of communicating an action, since there 
 can be no doubt that its effects continue to be produced equally 
 after the removal as during the presence of the cause, when once 
 this cause has impressed its mode of action upon the organism. 
 What the mode of this impression is, and what part of the system 
 is the subject of it in the first instance, w T e have now to enquire, as 
 also into the order of the phenomena subsequently produced and 
 constituting the formed disease. 
 
 The generally received opinion seems to be that the nervous 
 system is the subject of the first morbific impression, and its de- 
 rangements the first in the morbid series constituting fever. 
 
 This doctrine is thus maintained by Dr. Southwood Smith 1 — 
 " The immediate exciting cause of fever is a poison which operates 
 primarily and specifically upon the brain and spinal chord. The 
 diseased state into which these organs are brought by the operation 
 of the poison, deprives them of the power of communicating to the 
 system that supply of stimulus, (nervous and sensorial influence,) 
 which is requisite to maintain the functions of the economy in the 
 state of health. The organs, the seats of the functions, deprived 
 of their supply of nervous influence, become deranged, the derange- 
 ment in each taking place in a fixed order and in a determinate 
 manner. 
 
 "Subsequently to the nervous and the sensorial, the organs the 
 next to suffer are those of the circulation, then those of respiration, 
 and, ultimately, those which belong to secretion and excretion. 
 The condition of the nervous system, which produces this derange- 
 ment in this circle of organs, occasions further, in that portion of 
 the circulating system which consists of the capillary blood-vessels, 
 that peculiar state which constitutes inflammation : hence inflam- 
 mation is almost always established in one or more of the organs 
 comprehended in the febrile circle and sometimes in all of them." 
 In another passage the same writer says — "The more closely and 
 extensively the subject is investigated the more clear and satisfac- 
 tory the evidence becomes, that the great primary cause of fever is 
 a poison, the operation of which, like that of some other poisons, 
 the nature of which is better understood and the action of which 
 has been more completely examined, is ascertained to be upon the 
 nervous system. How these poisons act upon the nervous system 
 we do not know, nor can we possibly know as long as we remain 
 
 1 Treatise on Fever. 
 
160 HUDSON ON THE POISON OF FEVER. 
 
 so profoundly ignorant of the nature of the action of the nervous 
 system in the state of health." 
 
 It will be seen that Dr. Smith's argument, like that of others al- 
 ready examined, is rested upon a fallacious analogy to certain other 
 poisons, and like these is open to the fatal objection, that such 
 poisons really produce their effect upon the nervous system subse- 
 quently to their diffusion through the blood. It moreover lacks the 
 support derived in the former cases from the occurrence of a nervous 
 shock, since such rarely, if ever, attends exposure to the paludal 
 sources of fever. On the other hand, some of the arguments for a 
 modified humoral theory before adduced, apply with greater force 
 to this than the animal miasm, and additional ones are not wanting 
 to strengthen the proofs that all derangements of function in fever 
 are subsequent to the introduction of the poison into the blood, and 
 the consequent vitiation of that fluid. For, its latency is even more 
 remarkable than that of the animal infection of typhus, while a 
 close observation of the state of the patient, during this period, will 
 show a derangement of the secreting and excreting functions, which 
 seem to be labouring to rid the system of the poison, or of those 
 products which it has a tendency to generate in the blood ; again, 
 we can not unfrequently trace the abrupt termination of this period, 
 and the supervention of formed disease to a suspension of the de- 
 puratory action, by cold, intemperance, or any other cause which 
 disturbs the order of the excreting functions and arrests the elimi- 
 nation of the morbid product. Thus, in an exquisitely marked 
 case of paludal fever, which was lately under my care, and which 
 terminated fatally after large evacuations of blood from the bowels, 
 it was remarked spontaneously by the patient's friends that, for six 
 weeks before fever commenced, not only had he suffered from ca- 
 pricious appetite and irregular bowels, but that a remarkable thick 
 copious deposit had been constantly present in his urine. During 
 this period he had been living and sleeping in immediate proximity 
 to a collection of filth, which at times filled the house (in other 
 respects a cleanly and comfortable one) with an insufferable putrid 
 effluvium. 
 
 This instance also illustrates the cumulative property of the poi- 
 son, which is much more remarkable than that of the animal 
 infection. Unlike the latter, which is often most severe upon its 
 first introduction into a family, the poison of malaria seems com- 
 monly to affect each successive patient more severely than the pre- 
 ceding. 
 
 To what can this be attributed but to the accumulation in the 
 blood consequent upon longer continued imbibition of the poison ? 
 This is similar to the explanation offered by Cruveilhier, of the 
 general incurability of phlebitis from the absorption of pus. Ex- 
 periments have shown, that from a single injection of putrid pus 
 into the vein, an animal may, after copious evacuations, recover: 
 he therefore concludes that similar success might attend the eva- 
 cuant treatment of phlebitis, did not the renewal of the sources of 
 
HUDSON ON THE POISON OF FEVER. 161 
 
 infection follow the incessant renewal of the pus. But we can not 
 only detect the presence and agency of the poison in the circulation 
 through the deranged excretions, but also occasionally in the phy- 
 sical changes of the blood itself previous to the occurrence of 
 formed disease. The following observations of Dr. Potter 1 on this 
 subject, are highly interesting and important, and from the care 
 and accuracy with which they appear to have been made, are en- 
 titled to great weight in the discussion of the mode of access of 
 fevers, arising from malaria. He says, " it was remarkable in all 
 cases in which it was deemed expedient to bleed, the blood wore 
 the same general appearances. After a separation had taken place, 
 the serum assumed a yellow shade : often a deep orange, and a 
 portion of the red globules was invariably precipitated. 
 
 "It occurred to me that if the remote cause resided in a common 
 atmosphere, the blood of all who had inhaled it a certain time 
 would exhibit similar phenomena. It accorded with the pathology 
 I had conceived, to conclude, that all who lived in an atmosphere 
 so impregnated were constantly predisposed, and that an additional 
 or exciting cause only would be required to develope the symptoms 
 and form. To ascertain the appearances of the blood in subjects 
 apparently in good health, I drew it from five persons who had 
 lived during the whole season in the most infected parts of the city, 
 and who were, to every external appearance and inward feeling, 
 in perfect health. The appearance of the blood could not be dis- 
 tinguished from that of those who laboured under the most inve- 
 terate grades of the disease. As this experiment might have been 
 considered inconclusive unless the blood could be compared with 
 that of those who lived in a purer atmosphere, remote from the 
 evolution of miasmata, I selected an equal number of persons who 
 lived on the hills of Baltimore County, and drew from them ten 
 ounces of blood. The contrast in the appearances was so mani- 
 fest that no cause for hesitation remained. There was neither a 
 preternaturally yellow serum, nor a red precipitate; the appear- 
 ances were such as we find in the blood of healthy subjects. A 
 young gentleman, having returned from the western part of Penn- 
 sylvania on the 10th of September, 1 drew a few ounces of blood 
 from a vein on that day ; it discovered no deviation from that of 
 other healthy persons. He remained in my family till the 26th of 
 the month, and on that day I repeated the bloodletting. The serum 
 had assumed a deep yellow hue, and a copious precipitate of red 
 globules had fallen to the bottom of the receiving vessel. Of the 
 six persons whose blood assumed those indications of the remote 
 cause, four were seized with fever during the epidemic ; the other 
 
 1 Quoted by Dr. Tweedie, Art. Fever, Cyclopaedia of Practical Medicine. 
 
 Dr. Tweedie's own expressed opinion is " whether the opinion of the 
 older writers, that in fevers originating from contagion, the contagious prin- 
 ciple alters the properties of the blood be correct or not, we certainly think 
 the strong analogy in the cases alluded to tends to confirm the supposition 
 of typhoid fevers originating in diseased blood." 
 
 5 — f 6 hudson 
 
162 HUDSON ON THE POISON OF FEVER. 
 
 two escaped any formal attack, but complained occasionally of 
 headache, nausea, and other indications of disease." 
 
 Similar experiments were instituted by Dr. Stevens, and with a 
 like result, the blood being black in colour, and evidently deranged 
 in its properties previous to the commencement of the fever. 
 
 It might almost be considered unnecessary to strengthen the in- 
 ference from such facts as these, by observing on the effect upon 
 the blood of the gases, evolved from sources which we consider the 
 evidence already adduced proves to contain a fever poison, when 
 these are presented in a sufficient degree of concentration to pro- 
 duce rapidly fatal effects. 
 
 Describing the consequences of exposure to the emanations from 
 Parisian privies, Dr. Christison says: — "The appearances in the 
 bodies of persons killed by these emanations we fluidity and black- 
 ness of the blood, a dark tint, of all the internal vascular organs, 
 annihilation of the contractility of the muscles, more or less red- 
 ness of the bronchial tubes and secretion of brown mucus there as 
 ivell as in the nostrils, gorging of the lungs, an odour throughout 
 the whole viscera, like that of decayed fish, and a tendency to early 
 putrefaction." 
 
 With these and similar facts before us, we cannot agree in the 
 sweeping decision of Dr. Smith, that "changes in the fluids can 
 only be second in the series of morbid events : they can never hold 
 the first place in that series : they can never be antecedents or first 
 causes, but merely sequents or effects." 1 We rather think that the 
 evidence existing on the subject, if fairly examined, points to the 
 blood as the seat of the primary operations of the morbific agent, 
 and the subject of the changes which it is a part of its condition 
 necessarily to produce. And regarding all derangements of the 
 functions occurring in fever as the consequences of the molecular 
 changes in that fluid, we proceed to examine into the order in 
 which these consecutive phenomena occur — the mode of their pro- 
 duction, and their mutual dependence one upon another. 
 
 Supposing Dr. Smith's to be a fair exposition of the views gene- 
 rally entertained in this country, we find, upon reverting to his 
 chapter on the theory of fever, that the doctrine maintained is, that 
 subsequently to the supposed primary nervous impression, "the 
 organs the next to suffer are those of the circulation, then those of 
 respiration ; and ultimately those which belong to secretion and 
 excretion. The condition of the nervous system which produces 
 this derangement in this circle of organs, occasions further in that 
 portion of the circulating system which consists of the capillary 
 bloodvessels, that peculiar state which constitutes inflammation : 
 hence inflammation is almost always established in one or more of 
 the organs comprehended in the febrile circle and sometimes in all 
 of them." If this passage admits of a precise construction it must 
 be that in consequence of a certain impression on the nervous 
 
 1 On Fever, page 330. 
 
HUDSON ON THE POISON OF FEVER. 163 
 
 system a state of general inflammatien exists (or at least a state ap- 
 proaching to inflammation) in the capillaries of all the organs, and 
 which is equally likely to become actual inflammation in any of 
 them during fever. Without denying this frequency of visceral 
 inflammation in fever, or the great necessity of recognising and 
 combating it, it may be reasonably doubted if so variable and non- 
 essential an occurrence — with one exception — or one so dependent 
 for its existence and its seat upon accidental causes — as season, 
 atmosphere, epidemic influences, states of constitution, &c. — as 
 these local inflammations are, can be properly admitted into the 
 discussion of a theory of fever. Either this combination of inflam- 
 mation in some organ, with a peculiar state of the nervous system, 
 is necessary to constitute fever, or it is not. That it is, seems un- 
 likely, since morbid anatomy fails to detect it in a large proportion 
 of instances. If it be not, then, according to this theory, nothing 
 will remain but a certain peculiar affection of the nervous system to 
 account for the phenomena of fever. But in the kind of fever un- 
 der consideration there is a local affection generally regarded as 
 inflammatory, and which is so constantly present and found to ex- 
 ercise so great an influence on the disease as to have been consi- 
 dered by some eminent pathologists to be the essential cause of 
 typhoid fever. It is that affection of the mucous glands of the 
 small intestines described under the name of dothinenteritis. This 
 affection claims a special consideration, since no one can impar- 
 tially examine the evidence put forward in support of their views 
 of the pathology of fever by Louis and Chomel, in France, or the 
 cases incidentally published in the writings of Bright, Tweedie, 
 Smith, Graves and Stokes, Hodgkin, &c. in this country, without 
 being convinced that in some forms of fever — which farther ex- 
 amination will show to be paludal fever — this dothinenterite is a 
 constant and a most important complication, if indeed it be not the 
 pathological cause of the disease. 
 
 But if we seek an explanation of its occurrence in Dr. Smith's 
 theory, we are first at a loss to know why an impression on the 
 brain and spinal chord should lead to consequent, inflammation in 
 a part the most remote of any from their influence, and whose 
 functions are under the control of a different portion of the nervous 
 system. Then, in very many cases, we find that the symptoms of 
 intestinal irritation preceded this nervous impression — that in 
 others, in which death took place at an early period of fever, it was 
 found far advanced — as by Louis so early as the eighth day — and 
 could not therefore be regarded as a secondary phenomenon. And 
 that in other cases, in which the poison was presented in so con- 
 centrated a form that death took place before fever could be esta- 
 blished, the glands of Peyer exhibited the same appearance as in 
 that disease. The following -interesting case of this kind is given 
 by Dr. Christison. 
 
 In August last, twenty-two boys, living at a boarding-school at 
 Clapham, were seized in the course of three or four hours with 
 
 6* 
 
164 HUDSON ON THE POISON OF FEVER. 
 
 alarming symptoms of violent irritation in the stomach and bowels, 
 subsultus of the muscles of the arms, and excessive prostration of 
 strength. Another had been similarly attacked three days before. 
 This child died in twenty-five, and one of the others in twenty- 
 three hours. On examination after death, the Peyerian glands of 
 the intestines were found in the former case enlarged, and, as it 
 were, tuberculated : in the other, there were also ulcers of the 
 mucous coat of the small intestines, and softening of that coat in 
 the colon. A suspicion of poisoning having naturally arisen, the 
 various utensils and articles of food used by the family were ex- 
 amined, but without success. And the only circumstance which 
 appeared to explain the accident was, that two days before the first 
 child took ill, a foul cesspool had been opened, and the materials 
 diffused over a garden adjoining the children's play ground. This 
 was considered a sufficient cause of the disease, by Dr. Spurgin 
 and Messrs. Angus and Saunders of Clapham, as well as by Drs. 
 Latham and Chambers and Mr. Pearson, of London, who person- 
 ally examined the whole particulars." There cannot, we think, 
 be a doubt that their opinion was correct, and that nothing but the 
 rapid termination prevented the developement of the phenomena of 
 fever in these cases ; but in fairness to Dr. Christison, it should be 
 added, that he considers "this opinion cannot be received with 
 confidence by the medical jurist and the physician, since it is not 
 supported by any previous account of the effects of sulphuretted 
 hydrogen." Perhaps these cases may receive some confirmation 
 from the following report (certainly not a full one) of a similar ac- 
 cident by Dr. Arnott. 1 " In a mews behind Bedford-square, a stable 
 had been let for a time to a butcher, and a heap of dung had been 
 formed at the door, containing pigs' offal, pigeons' dung, &c. During 
 the act of removing this heap, a coachman's wife and her three 
 children, of an adjoining stable, sat for a time at an open window 
 nearly over the place, until the insufferable stench drove them 
 away ; two of the poor children died of the poison before thirty-six 
 hours, and the mother and other child narrowly escaped." 
 
 In Dr. Christison's cases the description of the appearances of 
 Peyer's glands exactly corresponds (especially the first case) with 
 Dr. Bright's description, and with the representation given in one 
 of the plates in his great work. As also with the minute investi- 
 gations of Dr. Staberoh, who regards the first stage of the follicular 
 affection, as ^an infiltration into the mucous coat, and especially 
 the crypts called Peyerian glands," but also taking place, as he has 
 repeatedly seen it, in different parts of the colon, "and to which he 
 considers the inflammation of the mucous membrane secondary." — 
 (Dublin Journal, vol. 13.) 
 
 But farther — if dothin-enterite were a consequence of disordered 
 circulation depending upon an impression on the brain and spinal 
 chord, we might expect to meet it in other cases in which these 
 
 1 Fourth Report of Poor Law Commissioners, p. 106. 
 
HUDSON ON THE POISON OF FEVER. 165 
 
 organs are engaged, as in the periodic fevers and in typhus : but 
 we do not, nor can any other local inflammation be named as 
 similarly constant in these diseases, and filling its place in the 
 " febrile circle." On the contrary, M'Cartney, Armstrong, and 
 others, have fully proved that the vascular congestion commonly 
 found in these diseases is not of an inflammatory nature, and that 
 though it may remotely give rise in certain cases to an inflamma- 
 tory reaction for its removal, it is yet a distinct pathological condi- 
 tion. 1 
 
 Two other opinions may be entertained of the relation of dothin- 
 enteritis to fever. One, that it is the primary cause : thai fever is 
 the sum of the symptoms of this inflammation — the other, that it is 
 the specific effect of the septic poison from which typhoid fever 
 originates, and like the other symptoms of this disease, merely a 
 link in the chain of sequences constituting fever. 
 
 Perhaps the strongest arguments for the first of these opinions 
 are the large proportion of cases of typhoid fever in which it is 
 found to exist — the influence it exercises upon the severity of the 
 disease, and the effects of antiphlogistic remedies, more especially 
 of topical bloodletting. It will be presently seen that the two first 
 circumstances are equally well explained upon the second opinion. 
 With reference to the effects of bloodletting it must be admitted 
 that a very considerable amelioration of symptoms, and not unfre- 
 quently their total removal, has followed timely and free abstraction 
 of blood, especially by leeches applied over the affected intestine, 
 and not only are the tenderness and pain in the part, with the me- 
 teorism and diarrhoea thus relieved, but the headache, thirst, pulse, 
 and other general symptoms commonly undergo at least a tempo- 
 rary and partial improvement. But it may be doubted whether 
 this is to be attributed so much to the removal of inflammation as 
 to an impression made upon the general disease, by the new move- 
 ment given to the circulation in general by the smallest local ab- 
 straction of blood, and which is felt in eyery part of the system. 
 
 One or two circumstances may be cited in proof of this dynamic 
 effect of bleeding, and to illustrate its application to the present 
 case — 1st, the well known fact that the impression made upon the 
 central organ of the circulation by the bleeding from a few leech 
 bites is totally disproportionate to the quantity taken away. 2d. 
 The effect of leeching, or bleeding in some other disorders in which 
 no supposition of inflammation could exist. In amenorrhosa, for 
 instance, we have known the disorder of several months' standing 
 removed by the application of a few leeches to the inguinal region 
 before the leeches were themselves removed. In ague also, an 
 effect almost equally marked may be sometimes produced by the 
 
 same means. The following short case illustrates this. C. F , 
 
 set. 20, was admitted into the Navan Hospital on the 22d of Feb- 
 ruary, labouring under tertian ague. The fit comes on two hours 
 
 1 For Dr. M'Cartney's observations, see Dub. Med. Trans, vol. ii. p. 574. 
 
166 HUDSON ON THE POISON OF FEVER. 
 
 earlier at each period. Has some tenderness on pressure, and ful- 
 ness of epigastrium, thirst, tongue red at tip and edges — previous 
 to entering hospital took two emetics and an aperient. A fit took 
 place about 3 a. m. on the 21st, and might be expected to recur at 
 1 a. m. on the 23d. I ordered 12 leeches to be applied on the 
 evening of the 22d to the epigastrium, and a draught to be taken at 
 bed time, containing twenty drops of laudanum. The fit occurred 
 at 5 a. m., four hours later than it was expected. On the 25th it 
 came on at seven, and the leeching being repeated on the evening 
 of the 26th, he sweated copiously during the night, and had no 
 return of the fit. There was a slight return of it five days after, 
 but from this time he got rapidly well. 
 
 Without entering farther into the discussion of the theory, that 
 dothinenieritis is the cause of the febrile phenomena, we pass on to 
 submit certain considerations in support of the view which regards 
 it as an effect not of the fever or of the state of the nervous and 
 circulating systems produced by the fever, but as the direct effect 
 of the poison itself — as one (probably the first) of the links in the 
 chain of sequences, constituting- fever, and one upon the occur- 
 rence of which some of the others may probably depend. This 
 view approaches nearer to that of Louis, who is of opinion that the 
 affection of the follicles occurs in the beginning of the disease, than 
 to that of Chomel, who seems inclined to admit its classification 
 among the secondary inflammations, but differs from the definition 
 of the former eminent pathologist, inasmuch as it seeks to establish 
 the agency of a morbid poison as the cause of fever, in place of his 
 decision "that the cause is unknown" The following extract 
 from his summary of the diagnostic symptoms of typhoid fever is 
 important, as containing two particulars which we shall find to 
 have a bearing upon this inquiry. 
 
 " Maladie aigue accompagnee d'un mouvement febrile plus ou 
 moins intense, variable dans sa duree; propre aux jeunes sujets, 
 principalement a ceux qui se trouvent depuis peu de temps au 
 mileau de circonstances nouvelles pour eua;, dont la cause est in- 
 connue ; debutant par un frisson violent, 1'anorexia, la soif, et dans 
 la tres grande majorite des cas par des coliques et la diarrhee" &c. 
 
 The two circumstances here mentioned by Louis, of the subjects 
 of typhoid fever being those newly exposed to influences, the na- 
 ture of which he concludes are not known — and the diarrhoea 
 which ushers in the complaint — we conceive tend to support the 
 theory that the intestinal affection is a consequence of the effort 
 made by the excreting organs — more especially the liver — to rid 
 the system of the poison which has been introduced into the blood. 
 It is easy to conceive that the native of Paris, born and brought up 
 in the atmosphere of its fosses, and drinking all his life the tainted 
 waters of its wells and river, may habitually eliminate from the 
 blood such products as are thus taken in unfit for assimilation or 
 nutriment, and that to a constitution unused to such a task the 
 consequence of taking into the circulation the same decomposing 
 
HUDSON ON THE POISON OF FEVER. 167 
 
 substances should be different. And if we aid our conception of 
 this fact by a reference to what takes place in the different classes 
 of persons exposed to malaria of other kinds in temperate climates, 
 we shall see why intestinal affections should be among the first 
 consequences of the process ; for it will appear that the liver is the 
 organ by means of whose excretions the poison is attempted to be 
 got rid of, and according to the facility with which this is performed 
 or otherwise, will be the chances of escape or the contrary, from 
 the effects of the poison. It is well known that, while the lungs of 
 a native of a warm climate are liable to become diseased upon re- 
 moval to a cold one, the liver is the organ prone to suffer upon the 
 inhabitant of a cold removing to a warm climate. It is also found 
 that the stranger from a colder country will rapidly contract fever 
 from exposure to malaria in a temperate climate, while the person 
 newly arrived from a warm one will not be similarly affected until 
 that change in the order of his functions termed acclimatization has 
 taken place, and he becomes assimilated in habits to the inhabitant 
 of the same latitude. 
 
 The following are the data upon which the proof of the connec- 
 tion of diseased mucous follicles with the peculiar effects of a mor- 
 bid poison upon the biliary excretion, may be rested. 
 
 1st. It may be considered as admitted, that the special characters 
 of substances fitted for assimilation are absence of active chemical 
 qualities, and the capability of yielding to transformations ; and 
 that every substance may be considered as nutriment, which loses 
 its former properties when acted on by the vital principle, and does 
 not exercise a chemical action upon the living organ. 
 
 2diy. That in the progress of the functions of nutrition, certain 
 chemical and organic substances are produced, and from time to 
 time are present in the blood ; which products it is the office of the 
 different excreting organs to discharge from that fluid — the relative 
 activity of these organs depending partly upon the matter to be 
 eliminated, and partly on other circumstances ; thus we have seen 
 that, in one situation the lungs assume a disproportionate activity, 
 in others, the liver, &c. 
 
 The foregoing propositions being admitted, the following maybe 
 regarded as convertible from them. If substances be introduced 
 into the blood which are not capable of assimilation or of affording 
 nutriment — whether from their chemical qualities or from their 
 condition (of decomposition) — it will follow that, instead of these 
 suffer in or the transformations which food undergoes to become as- 
 similated, the blood will undergo their transformation and disease 
 will be produced. 
 
 Also, that numerous modifications in the composition and condi- 
 tion of the compounds, produced from the elements of the blood, 
 may be the immediate result of the introduction into it of these 
 substances, and a change in the quality of the excretions may thus 
 be the first indication of the action of the poison, as well as of the 
 effort made to expel it. 
 
168 HUDSON ON THE POISON OF FEVER. 
 
 Numerous facts and observations tend to show that, in the case 
 of organic or putrid poisons, the liver is the organ by whose excre- 
 tions an attempt is made to rid the blood of the new products thus 
 formed in it. 
 
 As first — by a reference to the experiments of injection of putrid 
 pus, &c. into the veins of animals, performed by Magendie, Gas- 
 pard, Cruveilhier, &c. it will be seen that when the animal reco- 
 vered it was after copious discharges of a vitiated character from 
 the bowels ; to these discharges the last named writer attributes 
 the recovery, and adds, that it is a fundamental fact of pathology 
 that the intestinal canal is chiefly affected in diseases caused by 
 miasmata. 
 
 Again, if we refer to the published cases of poisoning from putrid 
 ingesta, we see that, besides those of irritant poisoning in which 
 the rapid rejection of the substances was followed by recovery, 
 there is another class in which, after an interval allowing of the 
 absorption of the poison into the circulation, a different set of symp- 
 toms followed, as in the following from Dr. Christison's work on 
 poisons : — " A family of five persons took for dinner broth made of 
 beef, which owing to its black colour the master of the family had 
 previously said to his wife he thought bad and unfit for use. 
 
 " In the course of some hours two boys were attacked with sick- 
 ness and vomiting, but appear to have got soon well, probably from 
 the early discharge of the poison. Next morning a washer-woman, 
 who had dined with the family, was seized with violent pain in 
 the bowels, diarrhoea, racking pains, and weakness in the limbs, 
 and did not recover for ten days. On the evening of the second 
 day the master of the house was similarly affected and was ill for a 
 fortnight. And a day later, his wife was also seized with a similar 
 disorder, preceded by soreness of the throat and tongue, and diffi- 
 culty of swallowing, and ending fatally in fourteen days." 
 
 It is worthy of notice that the severity of these cases was in pro- 
 portion to the interval allowed for absorption of the poison — alto- 
 gether their resemblance to the description of the symptoms of 
 typhoid fever, quoted from Louis, is remarkable. If 'we inquire 
 why the mucous glands of the lower portion of the ileum, are more 
 than other parts of (he intestine liable to suffer from this peculiar 
 derangement of the biliary excretion, we shall see reason to think 
 the cause is the same as would explain their existence in greater 
 number there than elsewhere, and that this is probably owing to 
 the fact of a second digestion or chymification being performed in 
 the ceecum, during which, it is believed by some physiologists, 1 
 that the entrance to the large intestine is closed, and bile collected 
 in the lower portion of the small intestine, which does not enter the 
 csecum till the secondary chymification is completed. The effect 
 of such a retention of an acrid and depraved secretion must be ob- 
 viously to produce irritation in the part subjected to its influence, 
 
 1 Schultz quoted by Muller. 
 
HUDSON ON THE POISON OF FEVER. 169 
 
 and the same deranged products of secretion, continuing through 
 much of the duration of the fever, we can account for this affec- 
 tion not seeming to be limited to any portion of that period, but 
 why commencing with it — frequently even preceding it, it ordina- 
 rily survives the continuance of the most prolonged disease. 
 
 This explanation also accounts for the disease in these glands 
 being found farthest advanced nearest to the termination of the in- 
 testine — for perforation occurring almost invariably close to the 
 caecum — for the lymphatic glands of the mesentery, corresponding 
 to the diseased follicles, becoming diseased — and for the severity of 
 these affections bearing a direct proportion to the severity of the 
 fever, and, as it would appear, to the amount of the poison imbibed 
 into the system. 
 
 This view of the relation of diseased follicles to the action of the 
 septic poison differs both from that which regards dothinenteritis 
 as the cause of fever, and from that which assigns to it a merely 
 secondary place in this affection. To the latter are opposed the 
 extremely frequent and early occurrence of abdominal symptoms 
 (as diarrhoea) in the typhoid form of fever. With the post mortem 
 appearances in subjects examined at an early stage ; while the 
 former is irreconcileable with the occasional absence of the lesion, 
 the frequent want of correspondence between its amount and the 
 gravity and fatal result of the fever, (a correspondence which should 
 exist if the other phenomena of fever were but the sympathies of 
 the affection of the follicles,) with the occasional persistence of the 
 local disease after the fever has subsided, and with the presence 
 (almost equally frequent in typhoid fever) of other lesions which 
 cannot be considered sympathetic of this, but must be ascribed 
 either to the immediate operation of the poison, or to that state of 
 the blood produced by it ; such are the softening of the spleen, 
 liver and heart, and the inflammatory affection of the brain and 
 thoracic viscera. 
 
 These pathological changes, as well as the derangements of 
 function constituting the febrile state, will probably be best ex- 
 plained by some such hypothesis as that advanced by Dr. Hodgkin, 
 which supposes the febrile state to depend upon a suspension, or at 
 least very considerable interruption of that process by which, 
 during health, the various parts of the system are continually un- 
 dergoing a change, the old materials being removed while others 
 are substituted in their place." 1 This hypothesis will be found 
 perfectly in accordance with that of the action of a morbid poison 
 
 1 Lectures on Mucous Membranes. Lect. 23. 
 
 Dr. Hodgkin's hypothesis seems to explain the great difference in the fa- 
 tality of fever as affecting the higher and lower classes of society, since by 
 the mode of life of the former, more nutriment being taken into the system, 
 and more organic matters, constantly present in the blood, an arrest of the 
 process by which they are eliminated, must naturally be followed by more 
 complete deterioration of the mass of circulating fluid, and more serious 
 injury to the functions and structure of the organs supplied by it. 
 
170 HUDSON ON THE POISON OF FEVER. 
 
 upon the hlood, since it will be the natural effect of the molecular 
 change produced in that fluid by the decomposing particles of the 
 poison so to modify it as to render it unfit to undergo the capillary 
 attractions constituting the processes of interstitial absorption, nu- 
 trition, and jecretion ; and thus instead of Dr. Smith's formula of 
 the order of successive derangements in fever — namely, derange- 
 ment of innervation — then of circulation, and lastly of secretions 
 and of the animal fluids ; the more correct one will probably be, 
 first the molecular change in the blood, then the suspension or 
 modification of the interstitial processes — or change of particles — 
 then certain derangements of innervation and of the heart's action, 
 and the result — formed fever. 
 
 According to this view, dothinenteritis is one of the phenomena 
 of the second stage in the action of the poison, and immediately 
 consequent upon certain modifications of the biliary (and probably 
 also the intestinal) secretion. Its occurrence cannot be considered 
 essential to typhoid fever, as the contamination of the blood may 
 cause the molecular changes upon which the foregoing hypothesis 
 supposes fever to depend without this — albeit its absence in typhoid 
 fever is very rare — while, on the other hand, it may exist without 
 fever necessarily folio wing", for we frequently see that, of a number 
 of individuals exposed to the same source of miasm, some will 
 suffer an a'tack of typhoid fever, while others will be affected with 
 diarrhoea or dysentery : a fact which is explained by a reference to 
 those experiments of Gaspard, in which the recovery of the animal 
 after putrid injection, was attended with profuse and offensive dis- 
 charges — seemingly the mode of relieving the blood from the pre- 
 sence of the poison. 
 
 Reference has been already made to another set of cases, in which 
 dothinenteritis occurs without fever: those namely, in which the 
 poison was so concentrated as to produce a rapidly fatal effect, and 
 where examination after a diarrhoea of only a day or two showed 
 the same peculiar affection of the follicles as in typhoid fever ; the 
 inference from such cases taken conjointly with those of fever from 
 the same causes without dothinenteritis, must be that this lesion is 
 neither cause nor effect of the fever \ but a concurrent and contin- 
 gent effect of the poison. Most of the other pathological changes 
 of fever are to be explained by the alterations in the constitution of 
 the blood. Such is evidently the cause of the softening of the 
 spleen so invariably present in typhoid fever, and such a little con- 
 sideration will show to be the cause of the congestive character of 
 the typhoid inflammations : for the occurrence most likely to follow 
 such a change in the molecular attractions of the blood as will in- 
 terfere with its capillary circulation, is stagnation in this part of 
 the system, of which the consequences are venous congestion, pas- 
 sive hemorrhages, and the softening of parenchymatous organs. 
 The stagnant character of the typhoid pneumonia has been re- 
 marked by many ; thus Dr. Williams saj^s, "it may be almost a 
 
HUDSON ON THE POISON OF FEVER. 171 
 
 question whether in these cases the local disease in the lungs is 
 not rather a congestion of blood in an altered state than an inflam- 
 mation, and it is very commonly the sequel rather than the cause 
 of the fever,'"- — an opinion which seems fully warranted by dissec- 
 tion, as well as consistent with the modifications of the physical 
 signs in this form of disease. 2 Huxham was so much struck with 
 this connection of the local affection and diseased blood, that he 
 compared the state of the latter in these cases to the scorbutic habit ; 
 and Andral countenances this analogy in the following passages. 
 "The ataxo-adynamic fever recognises ibr its commencement some 
 alteration of the blood, whether this alteration may have taken 
 place spontaneously, and produce a sort of acute scorbutus, or it 
 may follow the introduction of deleterious agents, as miasms, virus, 
 matters in a state of putrefaction; these agents after having modi- 
 fied the composition of the blood come to poison the nervous cen- 
 tres. Then the disease is everywhere, where blood and nerves are 
 to be found, and in every part lesions may occur which perform but 
 a secondary part in the production of the symptoms. 3 
 
 Again — " Congestions of the parenchymatous tissues and mem- 
 branes are tolerably frequent during the course of fevers. These 
 congestions seem to depend on the rupture of equilibrium between 
 the globules and fibrine ; they are very frequent in typhoid and 
 typhus fevers, and small-pox ; the spleen and other parenchyma- 
 tous tissues are usually congested in these diseases, and a diminu- 
 tion of fibrine as compared with the globules (whether absolute or 
 relative) is the alteration of the blood observed in these maladies. 
 
 " The ancients concluded from the phenomena just mentioned 
 that in the diseases in question, the blood is altered, and that its 
 elements have a great tendency to separate. They designated by 
 the phrase putridity, that morbid condition in which the vital 
 powers seem to yield to physical causes, and the blood becomes 
 putrescent. Borden, whose opinions as to the nature of typhoid 
 fever are remarkably sagacious and philosophical, does not hesitate 
 to consider that malady as connected with a general condition of 
 the system, which he designates by the name of acute scurvy. 
 This phrase is not inaccurate, so far as regards the condition of the 
 blood. A diminution of the quantity of the coagulable material of 
 the blood is a general fact observed in all great febrile disturbances; 
 thus in miasmatic fevers there is first absorption of the miasma, 
 and immediately after, the only prominent phenomenon is an al- 
 
 1 Article Pneumonia, Cyclop. Prac. Med. 
 
 8 See ray Observations on Typhoid Pneumonia, Dublin Journal, vol. vii. 
 for several dissections of this disease. 
 
 3 Clinique Medicale Translated, p. 610. Several cases are given, in 
 which all the symptoms of typhoid fever were produced apparently by 
 mental and bodily depiession, but after death no lesion was discovered — 
 for a striking case of this acute scorbutus, see Dr. Law's paper before 
 quoted. 
 
172 HUDSON ON THE POISON OP FEVER. 
 
 teration of the blood. This alteration which occurs in typhoid 
 fever is the efFect of some cause as yet unknown." 1 
 
 Hemorrhage is well known to be characteristic of typhoid fever. 
 That from the air passages is enumerated by Chomel among the 
 distinctive symptoms of the disease. Intestinal hemorrhage is also 
 a frequent and an unfavourable symptom, and indicative of a dis- 
 eased state of the blood. This hemorrhage is preceded by stagna- 
 tion. The softening- of viscera is always observed in conjunction 
 with an altered and fluid state of the blood. In some descriptions 
 of softened spleen by Andral and others, the blood contained in it 
 is compared to the lees of wine. 
 
 Sect. Y. — Characters of the disease produced by the putrid 
 miasm. — It has been remarked, that a general resemblance may be 
 traced between the disease produced by the infectious animal poi- 
 son of typhus and the exanthemata; its first and most striking 
 analogy being the almost constant presence of a peculiar eruption. 
 Another particular in which it resembles them and differs from the 
 disease now under consideration is the absence of any constant in- 
 ternal lesion ; the pathology of typhus being of a functional or phy- 
 siological kind, while that of endemic or typhoid fever is anatomical 
 and precise in its nature. The distinctive characters of the two 
 affections may be thus stated. In typhus, a poison is generated by 
 certain changes in the fluids of the living body, which, being re- 
 ceived into the blood of a healthy individual, has a tendency to 
 excite in that fluid the transformations from which it has itself 
 arisen, and by which it will be reproduced; a process during which 
 certain phenomena occur, as that of eruption (an effort apparently 
 to free the system from the presence of the poison,) and the conclu- 
 sion of which is marked by the presence in the excretions of the 
 material necessary for the generation anew of the disease in any 
 person into whose blood it may be received. All these phenomena 
 may occur without appreciable change in the structure of any 
 organ, and in fact death may be produced without any morbid ap- 
 pearance beyond that degree of congestion naturally connected 
 with the modification of its processes of nutrition and secretion. 
 
 In typhoid fever the events following the introduction of the 
 putrefactive poison are different ; it will appear upon examination 
 into these, that no new material of reproduction is generated, that 
 the eruption is not a true exanthema or identical with that of 
 typhus, being later in its appearance, less constant, more scanty, 
 consisting of successive crops rather than persistent and uniform, 
 as in typhus. A marked modification of the molecular changes of 
 the system occurs in this as in every variety of febrile movement, 
 but its continuance is evidently less uniform than in typhus, being 
 subject to alternations and remissions, at times approaching those 
 of the periodic fevers ; and the critical change attending its reso- 
 
 1 Lectures on the Blood, reported in Dublin Medical Press, Aug. 11, and 
 Provincial Medical and Surgical Journal, Aug. 21. 
 
HUDSON ON THE POISON OF FEVER. 173 
 
 lution is more gradual and liable to be less certain and complete, 
 as well as to recur by relapse, unlike that of typhus. But the most 
 important distinction consists in the fact that the typhoid miasm 
 has, like other putrid poisons, a tendency to be eliminated from the 
 system through the biliary excretion, in the course of which pro- 
 cess a peculiar form of irritation is set up in the alimentary canal, 
 while no such tendency can be asserted of the poison of true typhus, 
 in the majority of cases of which the biliary excretion suffers rather 
 a diminution than otherwise. 
 
 But it may be said it is by no means proved that the typhoid af- 
 fection of Louis and Chomel is of endemial origin, and in order to 
 establish the connection between miasm as a cause, and fever cha- 
 racterised by dothinenteriUs as the effect, either this must be proved, 
 or it must be made to appear that the fevers which in our own 
 country may be traced to this source are to be distinguished from 
 typhus by the intestinal lesion. 
 
 With regard to the French typhoid fever, we are led to infer 
 this conclusion from the following facts: the existence of such 
 miasm in abundance in the fosses, wells, and river of Paris — the 
 almost invariable occurrence of gastro-intestinal affections in those 
 newly-arrived there — the fact that typhoid fever attacks the same 
 class so constantly as to make a change of circumstances regarded 
 as one of the essential causes of the disease — and lastly, the testi- 
 mony of the most distinguished physicians that it is not propagated 
 by contagion. Let the experience of our large hospitals, with re- 
 ference to the infection of typhus, be compared with the following 
 statement of Andral. " In Paris, either in the hospitals or out of 
 them, we never recognised in this disease (dothinenteritis) the 
 slightest appearance of a contagious character. In the hospitals 
 we do not see it transmitted from the individual who brings it from 
 without to those who are lying 1 in the beds next his own ; neither 
 do we see that the patients who lie in a bed previously occupied by 
 a person who has recovered from, or who has died of a dothinente- 
 ritis, are attacked by it : neither are the physicians or medical stu- 
 dents who come there attacked with it, more particularly those who 
 have had to come in contact with patients labouring under the dis- 
 ease. Out of the hospitals what circumstances are more favourable 
 to contagion than those generally found combined in the case of 
 medical students who attend their companions when affected with 
 typhoid fever ? Shut up in a room which in general is very small, 
 they pay them the most assiduous and devoted attention night and 
 day ; if the affection were contagious almost all of them would con- 
 tract it, and yet we do not remember to have seen the disease even 
 once arise in this way in a healthy individual." 1 
 
 Louis does not mention contagion in his observation on the causes 
 of the disease, but Dr. Gerrhard states that, in conversation, he in- 
 formed him that he had never seen a case so communicated. 
 
 1 Spillan's Clinique Medicale, p. 728. 
 
174 HUDSON ON THE POISON OF FEVER. 
 
 But the question may be elucidated by an examination of some 
 of the published histories of fevers occurring in this country from 
 exposure to endetnial sources, from which it will be seen that in 
 numerous instances these were found to be attended with the cha- 
 racteristic dothineuteritis of the French typhoid affection. Thus 
 in London, after making every due allowance to the advocate of 
 the exclusive infectiousness of typhus, we must contend that the 
 writings of Dr. Armstrong, Dr. Southwood Smith, and others, 
 prove the frequent occurrence of coutinued fever from these causes, 
 while the treatise of Dr. Smith shows how large a proportion of the 
 fever of Loudon is of the intestinal kind — having all the characters, 
 symptomatic and anatomical, of the " typhoid affection." A similar 
 remark may be made of Dr. Tweedie's work, which contains nu- 
 merous cases of dothineuteritis, while it affords strong indirect tes- 
 timony to the endemial source in the statement as to the period of 
 the year at which the disease prevailed, and its remarkable subsi- 
 dence under the influence of low temperature, rain, and frost — 
 causes which exert a precisely opposite effect upon contagious 
 typhus. 1 
 
 1 Dr. Tweedie, wh© is by no means a strong advocate for the malarial 
 origin of fever, remaiks, that " cold and wet summers are always remarked 
 to be comparatively healthy, while disorders of the bowels in such seasons 
 are seldom observed. The number of patients admitted into the Fever 
 Hospital, in the Autumn months of the last three years, establish this prin- 
 ciple. In August, September, and October, 1827, there were 205; in the 
 same months of 1828, the numbers were 170 ; in the Autumn of 1829, only 
 94 were received. The cause of this progressive diminution is undoubtedly 
 to be traced to the cold wet summers of the last two seasons." 
 
 A similar remark has been made by many physicians as to Dublin; thus 
 Dr. Percival says, "it has long been observed, that protracted dry weather 
 is peculiarly productive of fever in Dublin ; and that rainy weather agrees 
 best with the general health of its inhabitants." And while he states that 
 the worst forms of typhous fever prevailed at an advanced period of the 
 winter, and were characterised by cerebral congestion, he thus distinctly 
 characterises the endemial fever: "But the seat of peculiar congestion in 
 the autumnal fever was the inner surface of the intestines, and sometimes 
 the mesenteric organs. The type of this epidemic was more irregular than 
 any other ; its invasion more obscure ; its progress and duration less defined. 
 The subjects of the disease were often broken down and declining constitu- 
 tions, in which the digestive organs had been long impaired, &c." Could 
 any description more resemble that of the dothinenteritis of Louis? Dr. 
 Davidson, who argues for the identity of the two fevers, meets the above 
 statement of Dr. Tweedie thus: — "An opinion exactly opposed to that of 
 Dr. Tweedie is given by Dr. Armstrong. He states, that in England, 
 typhus is evidently favoured by a low temperature, being most prevalent in 
 the cold seasons of winter and spring, generally abating or disappearing, as 
 the heat of summer advances, and often prevailing to a considerable degree 
 in cold wet autumns." This passage is extracted from his work on typhus, 
 in which Dr. Armstrong advocated the doctrine of contagion. At a later 
 period of his life he taught the exclusively malarial origin of fever, and in 
 his lectures adduces in proof of that doctrine the great prevalence of fever 
 in London during hot seasons, and particularly during the dry hot summer 
 of 1818. The only mode of reconciling these opposite opinions of the same 
 
HUDSON ON THE POISON OF FEVER. 175 
 
 A^ain, while Dr. Addison ascribes the numerous cases of syno- 
 chus and typhus presented at Guy's Hospital to river malaria, Dr. 
 Bright and Dr. Hod g kin prove the identity of many of the cases 
 received into that institution with the disease described by Louis. 
 Similar observations have been made in other places. In Bir- 
 mingham, dothinenteritis is stated to be the constant morbid ap- 
 pearance of the few cases of fever which occur ; and on referring 
 to Dr. Ward's account, already quoted, of a fever which he 
 clearly shows to have arisen from river malaria, we find it stated 
 that it was present in all the fatal cases. 
 
 In Dublin, Dr. Cheyne marked three periods occurring in his 
 experience, during which the contagious typhus, usually prevalent, 
 gave way to epidemics of intestinal fever, in which evidence of 
 malaria was frequently met with, but infection not so — the patho- 
 logy was that of dothinenteritis. These observations are confirmed 
 by others : thus, Drs. Graves and Stokes have published a number 
 of cases of peritonitis from perforating ulcer of the ileum, occurring 
 during one of these periods, 1826-29. Dr. Kennedy states that 
 the glands of Peyer were found by him to be more or less diseased, 
 in a large proportion of the cases of the same period, presenting, as 
 he remarks, a striking contrast in this respect to the fever (conta- 
 gious typhus) of 1837. 1 Dr. Stokes also says, "In the epidemic of 
 1826 and 1827, we observed the follicular ulcerations (dothinente- 
 ritis of the French) in the greater number of cases. In many in- 
 stances perforation took place, and the whole group of vital and 
 cadaveric phenomena corresponded almost exactly to the dothinen- 
 teric affection of the French authors." 3 
 
 We meet with similar evidence of two fevers in Glasgow. In 
 1836, says Dr. Stewart, 1 was much struck with the simultaneous 
 occurrence in the wards of the Glasgow Fever Hospital, of two sets 
 of cases in which the symptoms (however little most of them might 
 seem to differ when viewed individually) presented, when taken 
 collectively, characters so marked as to defy misconception, and to 
 enable the observer to form with the utmost precision the diagnosis 
 of the nature of the disease and the lesions to be revealed by dis- 
 section. More particularly it was remarkable to observe, that while 
 in the one disease the affection in those who presented no eruption 
 was so slight and of so short duration as to make it very question- 
 able whether it deserved the name of typhus, and while the fatal 
 cases presented an abundant and generally a profuse eruption \ 
 those labouring under the other, which equally and even in a 
 much higher proportion, went on to a fatal termination, rarely pre- 
 
 observer, is by supposing that he described the nature of each epidemic cor- 
 rectly as it was presented to him, but not being prepared to recognise a dis- 
 tinction in their nature, was naturally led by the evidently non-contagious 
 character of the last observed, to doubt the correctness of his views of the 
 origin of the first. 
 
 1 Medical Report of the Cork Street Fever Hospital. 
 
 2 Lectures, Lond. Med. and Surg. Journal. 
 
176 HUDSON ON THE POISON OF FEVER. 
 
 sented any, and then only a very scanty eruption. It was further 
 remarkable, that while in the one several successive patients had 
 either been restored to health or fallen victims to the severity of the 
 affection, the disease under which those laboured who lay side by 
 side with them, though characterised by much less urgent symp- 
 toms, pursued its gradual course through weeks and months con- 
 secutively, and in the majority of cases to a fatal issue. And 
 finally it was more remarkable still, that to complete the contrast 
 already so striking, dissection proved the existence in the one dis- 
 ease of most extensive local lesions, in the other, the absence of all 
 prominent local lesion whatsoever. 
 
 Dr. Stewart adds, "that during the summer and autumn of 1836, 
 the cases of typhoid fever were numerous, but from the month of 
 November in that year, (at which time both the type and amount 
 of typhus became more formidable) till June, 1838, not more than 
 a dozen cases, if there were even so many, and these at long inter- 
 vals, were admitted for treatment." 1 
 
 This evidence is pretty clear as to the existence of two forms of 
 disease. As to the causes, the highest authority in Glasgow on 
 this subject, Dr. Cowan, writing during the period referred to, and 
 with the cases before him, says — "many of the cases of the pro- 
 duction and propagation of disease must be ascribed to the habits 
 of our population, to the total want of cleanliness among the lower 
 order of the community, to the absence of ventilation in the more 
 densely peopled districts, and to the accumulation for weeks and 
 months together of filth of every description in our public and pri- 
 vate dunghills, to the over crowded state of the lodging houses re- 
 sorted to by the lowest classes, and many other circumstances 
 unnecessary to mention." 
 
 In Edinburgh, according to Dr. Christison, "the intestinal af- 
 fection has repeatedly presented itself in groups — the constitutio 
 dot hine titer ica, to speak in nosographical language, has repeatedly 
 appeared and disappeared as a subordinate or intercurrent epidemic, 
 in the course of the more general epidemic — typhus." And ac- 
 cording to Dr. Reid, such cases occur not unfrequently in the 
 country parts of Scotland, and are occasionally sent to the Edin- 
 burgh Infirmary. 
 
 In Liverpool we are informed they occur in an intercurrent 
 way, as in Glasgow, 2 and we need only refer to (he evidence before 
 the committee on the health of towns for proof of sufficient ende- 
 mial causes. 
 
 In the Navan Fever Hospital there have been for the last seven 
 years almost always two distinct forms of fever present, one or 
 other occasionally preponderating, so as at times nearly to exclude 
 the other. Thus for the first three years the prominent features 
 were pain, tenderness, and meteorism of the abdomen, diarrhoea, 
 
 1 On Typhus and Typhoid Fevers, Edin. Med. and Surg. Journ. No. 145. 
 
 2 See Dr. Lombard's Letter, Dub. Med. Journal, vol. x. 
 
HUDSON ON THE POISON OP FEVER. 177 
 
 and not unfrequently these symptoms combined with catarrh ; 
 several cases of perforation of the ileum occurred towards the close 
 of this period ; petechia? were not frequent and were late in their 
 appearance, and we had few instances of communication by conta- 
 gion. Daring the three following years a highly contagious fever 
 prevailed, and the symptoms and treatment were completely dif- 
 ferent, delirium, subsultus, dysphagia, being the ordinary symp- 
 toms, and diarrhoea being rarely met with ; — nearly every case 
 presented the measly efflorescence, and instances of contagion were 
 as numerous as they had been rare previously. During the present 
 summer the prevailing type has been the abdominal fever of the 
 first period, and instances of typhus are infrequent, certainly not a 
 fourth of the whole, and sent exclusively from a district in which 
 the epidemic of last year still lingers. 
 
 In America the existence of two kinds of fever has been main- 
 tained by Dr. Jackson and Dr. Gerrhard. The former says, in his 
 report on typhoid fever, " it is plain that there are at least two spe- 
 cies of continued fever, both in Europe and in this country, and 
 further researches may very possibly show more." 
 
 Dr. Gerrhard states, that " from the information we possess we 
 should conjecture that the two diseases (British or Irish typhus 
 and dothinenteritis,) are widely different in their symptoms, anato- 
 mical characters, treatment, and mode of transmission." 
 
 The following extracts from his able paper will show that the two 
 forms of fever exist in America at different periods and with distinct 
 characters, just as in our own cities. 
 
 " Dothinenteritis is by no means a rare disease in Philadelphia, 
 although less common than at Paris. In the essay alluded to, I 
 established the identity of the anatomical characters and of the 
 symptoms of the fever occurring at Philadelphia with that observed 
 at Paris. . . \ , The typhus fever which is so common throughout 
 the British dominions, especially in Ireland, is not attended with 
 ulceration or other lesion of the glands of Peyer For a pe- 
 riod of at least ten years, there has been no epidemic of this nature 
 at Philadelphia. In the year 1827, a large number of Irish emi- 
 grants were ill of a typhoid fever with ulceration of the small in- 
 testines, which was probably dothinenteritis, and during several 
 successive years there were more or less extensive epidemics of 
 remittent and intermittent fevers occurring in the neighbourhood 
 of the city, but not often extending into the central parts of the 
 town. In the winter of 1835-6, a form of fever not commonly met 
 with at the hospitals was observed from time to time. It was cha- 
 racterised by pungent burning heat of the skin, dusky aspect of the 
 countenance, subsultus, delirium, with great stupor and prostration, 
 but there was no diarrhoea, and but few symptoms referrible to the 
 alimentary canal. It was the disease which afterwards appeared 
 
 as an epidemic The evidence of contagion was direct 
 
 and conclusive ; three of the principal nurses and about a dozen 
 
 assistant nurses, besides a number of patients ill with various 
 
 5 — g 7 Hudson 
 
178 HUDSON ON THE POISON OF FEVER. 
 
 diseases were taken with the fever. There was only one nurse of 
 a ward in which many of the patients were collected who escaped; 
 but several of his assistants and patients were taken ill. The 
 wards in which the fever patients were placed were large and well 
 ventilated. The contrast between the two fevers in this respect 
 
 (their infectious character) is obvious Season of the 
 
 year. — The epidemic began in March and continued until August 
 — there were a few scattering cases afterwards. The summer was 
 
 unusually cool, and the spring and winter cold 
 
 Pathological anatomy. — In this large number of autopsies, amount- 
 ing to about fifty, there was but in one case, and that doubtful in 
 its diagnosis, the slightest deviation from the natural appearance of 
 
 the glands of Peyer The fact that the morbid 
 
 changes pathognomonic of dothinenteritis are not met with in the 
 typhus fever, would of itself seem conclusive that the two diseases 
 are no more identical than pneumonia and pleurisy. Although in 
 some respects the two affections are analogous and even similar ; 
 the radical difference of anatomical lesions is at least as well 
 marked as the distinction between the symptoms. It is indeed sin- 
 gular that there should be of late a strong tendency to confound 
 two fevers which were regarded as entirely distinct by some of the 
 older physicians." 
 
 In the above quotations we see strongly marked the differences of 
 the two affections as to prevailing season — symptoms, pathology, 
 and mode of transmission, and the similarity of each to one or other 
 of the two forms of European fever. 
 
 Having endeavoured to collect and arrange the testimony of the 
 best authorities as to the sources of the fever poison, we stop upon 
 the threshold of the extensive inquiry into the laws which regulate 
 the diffusion of the disease in an epidemic form. 
 
 To attempt this would require the fullest investigation into the 
 differences and analogies of the two affections, their modes of com- 
 bination in the same individual, and their occurrence in an inter- 
 current mode during the same epidemic period, all of which modi- 
 fications of disease would be found reconcileable with the theory of 
 two poisons ; the one having its elements in the blood, and repro- 
 duced in it ; the other a product of putrefactive decomposition, and 
 not reproduced in the human body ; while on the other hand Dr. 
 Davidson's recent essay contains in itself proof that his own theory 
 of a single typhoid poison is not tenable, since it involves the asser- 
 tion of the identity of two diseases, one of which (according to 
 him) requires to be kept up by an uninterrupted series of cases of 
 contagion, while the other, according to the best observers, never 
 propagates itself by contagion at all. In short, according to this 
 doctrine, we must believe that the same poison, shall at the same 
 time and place, and among the same collection of individuals, pro- 
 duce two diseases totally dissimilar in their mode of access, symp- 
 toms, pathology, treatment, and mode of transmission. 
 
ERRATA. 
 
 Page 95 — line 9. for account, read amount. 
 
 „ 106 — line 9, after on the, insert contrary. 
 
 „ 112 — line 27, for violent, read violet. 
 
 „ 115 — line 42, for committed, read admitted. 
 
 „ 125 — line 7. for receiving, read secerning. 
 
 „ 130 — line 4, for Bruserin, read Burserius. 
 
 „ 133 — line 11, for epidemics, read epidermis. 
 
 „ 135 — line 34, for epidemics, read epidermis. 
 


Library of Congress 
 Branch Bindery, 1903