excellent chapter on the economy of salt, may be seen in "Bordley's Notes on Husbandry and Rural Affairs," to which I beg leave to refer you for a variety of important and valuable information on this subject. (See the review of this instructive work in Med. Rep. Hexade I. vol. iii. p. 276.)

Knowing well your correctness of thinking and acting on the great question of our pestilential distempers, I have no doubt of your support, when I entreat you to assist me in putting our fellow citizens on their guard against the extensive and fatal evil of employing English salt to preserve any kind of flesh or fish from putrefaction. The manner in which pure muriate of soda acts in staying corruption, I formerly explained, in a paper addressed to Professor Woodhouse (Med. Rep. Hex. I. vol. ii. p. 274); but this Liverpool salt is so im pure that it does not quadrate with that theory, but stands in opposition to it; and by its diversity, indeed, confirms it. In discussing a subject so complicated and abstruse as that of our annual endemics, it is not a matter of surprise that they who' have little industry and small capacities should fall into the be lief of their being contagious, and of foreign derivation. Some of them will carry this error with them to their graves; but the majority, especially of the rising race, will take the right impressions without any difficulty, and continue to reason and to conduct properly all their days.

ARTICLE V.

OBSERVATIONS on the CONTAGIOUSNESS and IMPORTATION of YELLOW FEVER. By THOMAS DANCER, M. D. of Kingston, in the Island of Jamaica. Addressed to the Editors of the Medical Repository.

NDEBTED as I feel myself to the Medical Repository for much valuable information, I should be glad to evince my gratitude by contributing to so useful a publication. As I am impelled by the same motives that appear to actuate the ingenious writers in this miscellany, viz. the discovery of truth and the improvement of medicine, not by any desire for literary contention, I shall hazard some observations on a point which, being one of the greatest interest to humanity, has chiefly engaged the attention of the American faculty, and called forth their talents into exercise, viz. the contagiousness or non-contagiousness of Yellow Fever, and whether the Yel

low Fever is an imported disease; or one wholly of local and domestic origin.

It is greatly to be lamented that a due reverence for long established doctrines on the one hand, and a laudable ardour for discovery on the other, should alike tend to mislead us in our researches; and that the investigation of truth, in a matter of the greatest concernment to mankind-one on which the very existence of society in a great measure depends, should become an undertaking of almost insuperable difficulty. How else could it happen that so many medical, men, distinguished for talents, and no less so for a spirit of liberal and candid inquiry, should differ so widely from each other, and, at a short distance of time, from themselves; many of them having been led to change their opinion on the subject (as it is possible I may ultimately mine); which serves to show that, however simple and plain the question may seem, it is nevertheless involved in much intricacy. I will not presume that I can say much to elucidate it, or that I am competent " to set it in the best light it is capable of receiving, in order that the question may be brought to a fair and ultimate decision;"* but I shall obey the invitation given me of presenting my sentiments, if haply they may serve to bring such medical men as are disposed to consider the subject without prejudice, and apart from all other matters with which it is supposed to be connected, to a somewhat nearer point of agreement.

When "facts are more scrutinized, the advocates for either opinion will possibly find a ground of compromise." This is an event devoutly to be wished: for such differences among medical men are not creditable to the prefeșsion, nor conducive to the benefit of mankind.

A science like medicine will not always admit of definite language. This is apparent on many occasions, and is particularly so in respect to the terms infection and contagion; from the confounding of which together, or from assigning to each novel significations, proceeds, in a great measure, the obscurity that rests on the present question. Their etymological import, so critically ascertained in some late inaugural disserta

* Med. Rep. Hex. I. vol. vi.

† Some appear very unwilling to admit of the supposition of contagion, because of the consequences that might follow: but if contagion really does exist, are not the consequences of incredulity much more to be appre hended? I do not mean to defend the old quarantine regulations: they are absurd.

+ Dr. Seaman,

tions, is of little moment. It is the sense in which they are ordinarily understood, † by which we must be guided in this inquiry; and if we are to adhere to this, the pestilential yellow fever must be considered a contagious one.

Such diseases as the camp, hospital and jail fever, with ordinary typhus, which derive, or have been supposed to derive, their origin, not from marsh exhalations, &c. but from human effluvia, or emanations proceeding directly from the sick body, or else from substances imbued with these, have always hitherto, at least since the time of Sir John Pringle, been denominated contagious,§ in contradistinction to those arising as afore-mentioned, which it has been agreed to call infectious.|| That the pestilential yellow fever classes with the former, and not with the latter, there can be no manner of doubt; but if we are to adopt the new-coined distinction between infectious and contagious diseases, viz. that contagious diseases are only such as are occasioned "by morbid animal secretion, or by the vitiated product of living vascular action, like small-pox, vaccina, measles, lues venerea, &c. and which can affect the constitution only once," then the dispute is at an end. We may, however, be allowed to ask, Is this novel distinction so obvious as to be understood,** and so satisfactory as to be ad

* Inaugural Dissertation on Dysentery, by Dr. Quackenbos. Inaugural Dissertation on the Origin and Propagation of Yellow Fever, by Dr. Bayley. New-York. 1802.

† Contagion is that peculiar morbid poison which is prepared in the bodies of living animals, and which is communicated to others by contact, or by approaching too near them. Such was the acceptance of the word while it remained unwarped by prejudice, and till restricted to such diseases as occur only once, like small-pox and measles. (Med. Rep. Hex. I. vol. vi. p. 12.)

A distinction is to be made between the endemial yellow fever and the pestilential yellow fever. (See Chisholm.)

S" It is now generally allowed that the effluvia of living persons, confined in close situations, produce the poison of fever." (Ferriar.)

Cullen, Pringle, Lind, Chisholm.

See Med. Rep. Hex. I. vol. v. p. 186. vol. vi. p. 10. The former part of this definition may, perhaps, be admitted, but not the latter.

** I cannot help thinking that the lately adopted distinction between infection and contagion is ambiguous and inapplicable. Who can say with certainty that contagion belongs only to secreted matters, and that it is not attached to the matter of perspiration, and the halitus from the lungs, and other excretions? The advocates for the new distinction are not at all agreed how to class diseases under it. By some, lues venerea (as depending on specific virus secreted) is considerd a contagious disease. Happy would it be for mankind that it answered the definition, and that it occurred but once to the same person. (See Med. Rep.)

Rather than allow yellow fever to be contagious, like hospital fever, jail

mitted? I presume otherwise. Do none of the diseases depending on a specific secreted virus affect the constitution only once? Does it appear that there is no difference between vegetable and animal putrefaction? Can the emanations from the living body be considered of the same nature with those from dead animal matter?* May not the effluvia of the hu man body, under disease, be considered as having a different nature from what they have in health? and may they not, under many diseases, be specifically so?

We are confessedly alike ignorant with respect to the matter of infection and contagion;t but is there any just ground to conclude (although they should sometimes, as it is by many imagined, co-operate) they are the same, and that all fevers arise solely from one cause; or that typhus, jail, hospital, ship, and pestilential yellow fever, all originate in the same source as bilious remittent and intermittent fevers? If this were the case, why should not the phenomena of each be the same? But we see they are not so. There is an essential difference among them. They do not exist in the same seasons and situations, nor do they run the same course, &c.

It is become fashionable to consider the several kinds of fever as grades only of the same disease, and to talk of the different states of fevers, viz. the gangrenous state, &c. But fevers originate in so many different ways they differ so much in their mode of attack, in their progress, declension and termination, that I must continue to think they differ in genera according to the remote cause. "The remote causes of fevers are of two kinds, each producing a class of fevers, whose cha

fever, &c. it is by others confidently denied that these are so, and the fact, so well established, of prisoners having communicated to the judges and court at Oxford, &c. a disease they had not themselves, is indecently ri diculed. On the other hand, Dr. Cathrall (a champion for the new distinction) allows that typhus, hospital fever, &c. do not depend on a pu trefactive process, but on a vitiated secretion; if so, why may not the pestilential yellow fever depend on the same?

* See Ferriar, Med. Hist. vol. i.

It is, indeed, pretended that the one consists of hydrogen gas, or hy. dro-carbonate, and the other of the gaseous oxyd of septon. I am fully sensible of the importance of the new discoveries in chemistry, but I do not see that they are applicable to explain the composition of pestilential efflu via. As well may we attempt to explain the nature of any specific contagion, viz. that of small-pox, lues venerea, and the poisonous odors. Are not all these combinations of oxygen, hydrogen, and azote? but who can say in what proportions, or explain the quomodo of their combination { -For the fallacy of eudiometrical experiments, see Dr. Rush, Med. Rep. Hex. I. vol. vi. p. 163.

racter depends on the nature of the peculiar fluid constituting the base of the morbific effluvia."*

Upon what does this difference among fevers depend? Certainly upon the remote cause producing them,† which cannot be always putrefaction simply considered, for it does not appear that infection (contagion) always arises from putrefaction, and it is known to spread without its aid.

It would appear, then, that there is some material or essential difference between animal contagion and ordinary putrid exhalations, although it has been supposed there is some "intimate if not inseparable connection between them."§ There may be, perhaps, no such connection, or no effect arising from their chemical union; but they may reciprocally dispose the body to be acted on by each other. This would appear very evident from numerous acknowledged facts. Whichever opinion is admitted, it will serve, in some degree, to remove the ambiguity attending this difficult subject.

That the noxious effluvia and halitus from sick bodies may adhere to clothes, bedding, furniture, &c. and thereby become a seminium or fomes of the disease, will scarcely be denied by any one; and the advocates for non-contagion will not pretend that it cannot be so imported, or that the cause of it cannot be so imported;¶ but then they affirm it cannot by Chisholm, vol. i. p. 281.

† Ibid.

Persons concerned in putrefactive processes, and living in the neighbourhood of shambles, church-yards, &c. are not peculiarly liable to fevers. Infection or contagion is rarely, if ever, received from bodies who died of contagious diseases; not even from dissecting them, unless by inoculation. (See Ferriar, Med. Hist. and Facts, vol. i.)

"It must not, however, be concealed, that noxious effluvia do frequently arise from putrefying bodies in a certain state (perhaps from confinement); but the diseases produced thereby are inflammatory, not pestilential." (See as above.)

It appears, from the testimony of many medical writers who have had great opportunities for observation, that they frequently act in conjunction, and that fevers are combined. Of this opinion are Chisholm, Lempriere, Jackson, Lind, Clark, &c.-Putrid effluvia, generated on board of ship, may have the effect of changing the type and nature of the original fever, by superseding the action of the marsh miasmata.

With what force the contagious matter generating fever will adhere to furniture, and the walls and floors of rooms, may be seen in many extraordinary cases, particularly in one related by Dr. Brocklesby, in his Diseases of the Army. Six or seven persons died in succession of a malignant fever, being put into an infected room, notwithstanding every pains was taken to purify it, each time it was vacant, by fumigation, ablution, &c. At last the walls were new plastered, and the floor planed, and it then became safe. Was this contagion common putrid matter? ¶ See Inaugural Dissertation by Mr. Quackenbos.