Ill mAipm^fum^rnnyp^k^i^ • J IV MFMO VERITAS" A N ESS A Y READ BSrORX TUI JEFFliltsnN COLLEGE AND WASHINGTON LVLi.IM 01: LENDER 2. 1937. BY J. \V. Mt'NETTE. M I' V >v : oyay »v" Vj / NATCHEZ PRINTED BT CLARKE, nkMTCOIO AND CRllt. ( .YvK AN ESSAY. Notwithstanding the great diversity of opinions, entertain- ed by medical men, relative to the nature and production of yellow-fever miasm, and its operation upon the human sys- tem in producing that disease epidemically ; some points are admitted, on all hands, as facts attending its production, ex- tension, and destruction, in cities, and certain other localities. It is admitted on all sides, that, at certain times, a peculiar miasm is generated, which will excite, in healthy individuals who breathe it and who are not naturalized to it, a peculiar malignant fever, or disease termed by common consent, yellow fever: that this miasm, or aerial poison, may be confined in houses, rooms, and other similar places, with all its deleterious properties, even after the surrounding general atmosphere, which is unconfined and free in its circulation, has become en- tirely healthy: that this poisonous malaria, in rooms, ships, &c., insinuates itself into every opening, recess, or interstice, into which common air can penetrate, especially near the surface of the ground : that when diffused in a hot and sultry atmosphere, it has a property of extending itself gradually, and sometimes rapidly, and of imparting to that atmosphere a deleterious property, which will excite yellow fever:—or that it assimilates a sultry, hot atmosphere to its own nature, or impregnates it with the miasmatic poison, so as to produce yellow fever, and in this manner spreads through a city : that this miasm may become so concentrated, as to produce yellow fever in unacclimated persons who breathe it, even in very small quantities: or it may be so far diluted by pure, com- 4 mon air, as to produce no sensible effect in those who respire it freely: that it is heavier than the common air, and settles in the evening dews, and accumulates in low, damp places, near the ground; that it is more rarified by the sun, and de- stroyed entirely by cold, or the abstraction of heat down to 320 Fah. Then it must be admitted, that if it can be confined in a house, a ship, or a balloon, it can also be carried from one place to another, where it will be equally deleterious as before it was transported, provided its temperature be not re- duced too near 32" of Fahrenheit, and provided it be not too much diluted with pure, common air. If so, then it must be admitted, that it can produce yellow fever in any place to which it may be carried and breathed in accordance with the above conditions: or, a portion of it may be introduced, into a hot, confined, and contaminated atmosphere, and produce there the assimilating process; and thus in some degree ex- tend itself: and the miasm or infection thus generated, will be equally efficient in producing the disease, as the original source from which it was taken. This principle is exempli- fied in the infected air which is shut up in houses during an epidemic yellow fever. A storm, or gale of wind, may so completely carry off the out-door infection, that the epidemic will almost cease: yet so soon as the " leaven " of infection which is retained in the houses and enclosures, can diffuse itself, and again effect the assimilating process in the general air, the epidemic will again break forth, with renewed viru- lence. The malignity of the disease is in direct proportion to the virulence of the infection; and if, after such a change of weather, the disease again becomes equally malignant, the newly generated infection is equally deleterious with the orig- inal : and this, we believe, is the result of an assimilating process, which the infection can, and does effect, in a suitable atmosphere. It is admitted that yellow fever is endemic all the year within the tropics, and in some places more than in others: 5 that, although its habitation is properly intertropical, its great- est ravages are among northern strangers, and that it would not be known as an epidemic in the tropics, were it not for the constant influx of northern strangers, who, when numbers of them are attacked, sometimes cause the infection to become so concentrated that it will produce an epidemic even among the indigenous or acclimated inhabitants. This increase, or concentration of miasm, or infection, is apparently owing solely to the further vitiation of the local atmosphere, by the number of bodies laboring under that disease: for, in the West Indies, and other places subject to yellow fever, it is known to prevail generally among unacclimated persons or strangers, and does not attack the natives, until after a large number of strangers have died. Hence, m those countries and cities where it is endemic nearly all the year, it is called the " strangers' fever A It is known also, that when the in- fection ( or miasm) is sufficiently concentrated to produce yel- low fever, in its most malignant forms, among strangers and unacclimated persons, the natives, or naturalized inhabitants, if attacked at all, will be affected with it in a much milder form. It is generally admitted by all parties, when a city, or cer- tain district in a city, is attacked with yellow fever, that there exists in that district the peculiar miasm of yellow fever; and that strangers, or non-residents, or a portion of them, who pass into the infected district, and breathe the atmosphere so infected with yellow-fever miasm, will contract that disease; and that it will develope itself in their systems in five or six days, as a general rule : and that this disease may be devel- oped in such persons, even in its most aggravated forms, at any place to which they may have travelled in the interim, whether it be far or near. It is also admitted, that those who reside in an infected district, and have continued to breathe the air while the infection or miasm was weak, or generating in small quantities, acquire a partial immunity, by becoming a* (') Naturalized, or acelimated to it; but that they also will take the disease, and die from it, when the miasm becomes more abundant, or more virulent. This is exemplified every year ; for healthy, unacclimated persons have contracted the dis- ease in cities and places, while the resident inhabitants were healthy, or not affected with yellow fever. It is also known and admitted by all parties, that when yel- low fever is epidemic in any part of a city, that the infected atmosphere, when confined in a close room for several days, at a temperature of not less than 801 of Fahrenheit, loses none of its properties, but often acquires a new degree of vir- ulence. As before observed, it is known that this miasm, or infection, when it exists in abundance, as it does in all infect- ed places, diffuses itself into every recess and interstice into which common air can penetrate. Hence every chamber, every alley, street, avenue and cellar, within its limits, be- comes alike infected during an epidemic. It diffuses itself also in beds, bedding, and bales of blankets, and other porous articles, which always contain much air: and when retained in these, in a suitable temperature, it oftenacquires an increas- ed virulence, in like manner with that which has been con- fined in close rooms. But when, in addition to the infected air of the rooms, the beds are saturated with the secretions and exhalations of human bodies in disease, it is cal led/omi- te.s, ox fames, and is, decidedly, in all infectious diseases, more morbific than the infection diffused in the open air. In yel- low fever, the exhalations from the diseased body unquestion- ably add to the virulence of the infected air, when so confin- ed: hence this kind of infection, {or fames,) is more deleterious to all who breathe it, than the infection of the open air. By a careful estimate and calculation, it will be found, that a common feather bed, when stirred up loosely, contains from twenty to twenty-five cubic feet of air, varying according to its size; and each pillow will contain from two to four cubic feet of air; the feathers, if reduced to a solid, constitute less / than one-twf ntieth of that bulk. Blankets, and other cloth- ing, contain air likewise in proportion to their texture. Now ail these articles, in an infected district, become charged with the infected air of that district, just as they do with common healthy air, in a healthy season. The confinement of the in- fected air, so as to prevent its dispersion in the general atmos- phere, increases its power of producing disease, in proportion to the closeness and the temperature in which it is kept: and as yellow fever miasm and infection are destroyed by a temper- ature below 40'' Fahrenheit, it will acquire new virulence only when its temperature is above that point, and most at a temperature between 85 and 90° Fahrenheit. Now, if the open air of a certain district be capable of producing a cer- tain disease in those who breathe it, and if the air contained in beds, &c, be of the same quality, but more virulent, why should not this infected air, transported in such articles to an- other place, be capable of producing the same disease in those who there breathe it,as well as nearer the source of infection ? It would be a paradox if the mere act of transportation should neutralize its morbific properties. When a person sleeps upon a bed, or upon porous articles of bedding, whether charged with healthy or infected air, he of necessity breathes mo.re or less of it: his body presses out of a feather bed an equal bulk of air, which settles around him, and is respired with the common air of the room. Oth- er portions of it are likewise pressed out by each movement, or change of position, and are likewise respired. Thus, in sleeping upon abed one night, in all probability an individual presses out and respires all the air which it previously con- tained, whether healthy or infected. Thus far it matters not from Avhat source, or in what man- ner the poison of yellow fever is produced; or in what man- ner it produces its effects upon the human system. We will call it infection, and, for the sake of argument, admit that it is produced from any source which may suit the fancy of our 8 readers; still it must be admitted that it can produce the dis- ease called yellow fever, wherever it is respired in its undi- luted state; or when only moderately diluted with sultry, contaminated air. As to the peculiar nature and composition of this malaria, or poison of yellow fever, we know nothing, except by its effects upon the human system. Of its qualities, we know only by induction; and some of its general laws are deduced from repeated observation. In its effects upon the system, it is supposed by Baron Larrey* and others, and the supposition is sustained by my distinguished friend Dr. Cartwright.f of Natchez, that it is respired, and from the lungs, through the medium of the ganglionic system of nerves, produces its deleterious effects upon all the functions of animal and organ- ic life. Those deleterious effects, taken together, constitute yellow fever. Whether bodies laboring under yellow fever, are capable of throwing off any exhalation or effluvium possessing or de- riving morbific, properties, is a point yet disputed, although the general practice and the precautions inculcated, even by those who profess to believe it strictly non-contagious, tend to convince the unprejudiced, that all parties admit the princi- ple, although they deny the fact. The general admission, of those who disclaim either side of the question, is that, whin yellow fever makes its appearance as an epidemic in a city, or in a district of a city, each additional case tends still further to contaminate the air, or in other words to in- crease the virulence of the infection which is abroad. None but those who have been much conversant with yellow fever in the southern part of the United States or in the West Indies, should hazard an opinion to the contrary; even then their observation and discernment might be questiona- ble. If a body, or any number of bodies, laboring under ' r'ec Quarterly Jour, of For. Med. for April, 1832. Medical Recorder, vol 9, pp. 37,38,30. 9 this disease, can have any agency or influence in rendering the infected air more morbific, it must be by some exhala- tion thrown off from the lungs or skin; for it is hardly pos- sible that the general infection should be rendered more active and morbific by the loss or consumption of those por- tions of it required to produce the disease in those attack- ed. The consumption, or taking away a part, certainly cannot change the qualities of the remainder; and the only inference remaining is, that each body laboring under the disease, becomes a new source of contamination to the local atmosphere, however small may be the influence of each. The lungs and the skin are two of the greatest emunc- tories of the human system, and carry off more fluids in a gaseous form, than all the other excretories together. The fluid which passes off by insensible perspiration from the skin alone, in the form of gas or vapor, is equal to about five pounds in twenty-four hours; the same from the lungs, in the same time is about seven pounds—besides which each respiration deprives the air breathed of a part of its ogygen, and imparts to it a portion of carbonic acid gas or other gaseous compounds. The effluvia thus thrown out by a healthy body, or by a number of healthy bodies, are more or less pernicous to those who respire them;—how much more so then are they from bodies laboring under a pestilential disease? A portion of these exhalations is dif- fused in the air and wafted and lost by free ventilation in the general atmosphere; another portion is absorbed into the beds and bedding used by the sick, which in close air acquires a new degree of virulence. This is evidently ad- mitted by the non-contagionists, when they enjoin free ven- tilation and cleanliness as a precaution for safety, to those who nurse yellow fever patients. If this effluvium were not thrown off; or if it were not morbific, why enjoin the ne- cessity of cleanliness and ventilation about the sick chamber ? This may be infection, or it may not be. But all dis- 10 eases, and especially epidemics are in some degree infec- tious, and require more or less the precaution of cleanliness and ventilation. There are two kinds of morbific matter eliminated from bodies diseased; which is by some called contagion, or infection: the one is a gaseous exhalation, and the other a palpable matter of secretion. Some diseases throw off one kind of infection, and some the other: and some, such as small-pox, plague, and malignant erysipelas, throw off both kinds of infection. Others, such as vaccine pock, are communicated only by a palpable virus. Of those infections thrown off a gaseous form, some are so mild as scarcely to be estimated; others are more active, but still controllable by proper care to obviate the circumstan- ces of close air, concentration of the effluvium, by maintaining cleanliness and a proper temperature: others, as small pox, throw off a subtle exhalation, which, under nearly all circumstances, is infectious to the distance of a few feet, in all states of temperature. The same may be said of typhus and jail-fever, which requires a cool or cold damp air for its dissemination. The matter of contagion is originally morbific perse: other diseases give off an effluvium which becomes morbific, or infectious, under certain circumstances: thus of yellow fever. In relation to yellow fever, the great error of both the con- tao-ionists and the non-contagionists, is ultraism. The non- contagionist, because he believes that personal contagion has no ao-ency in the extrication of the miasm in the first instance, seenTsto think he would be inconsistent if he admitted person- al infection possible in any case. The contagionist, because he believes the. disease capable of reproducing itself by an infec- tious exhalation, thinks he would be inconsistent were he to admit the possibility of the disease being produced otherwise. Tnthis as in many other disputed questions, we believe out motto indicates the correct course " In medio est tuttssmus: or a disease may certainly be epidemic, and m some degree ii infectious also : and a disease may sometimes originate from some peculiar exciting circumstances, and yet, when pro- duced, possess properties slightly infectious. For the first case of the most infectious disease, must have originated with- out personal contagion. If a disease be capable of repro- ducing itself once in a hundred times, under the most favora- ble circumstances, it is certainly infectious. The infection is specific, because in all cases it produces the same disease as that from which the infection was produced. A disease which spreads alone by personal infection or contagion, makes but slow advances from one individual to another; while epidemic infectious diseases, attack a number of individuals in close succession. If yellow fever possess no, infectious qualities, or impart none to the air, or clothing, to beds, blankets, &c. why use the precaution of cleanliness and ventilation? Dr. Rush is the author of the most enlightened views on the subject of yellow fever; and when he wrote, a very gen- eral belief was, that it spread by contagion alone; or by the exhalations from one person to another, exclusively of an in- fected atmosphere. Under this state of things, the sick were often deserted to their fate, by those who believed in the doc- trine of specific contagion. They believed that it was pro- duced solely by communication with those sick of yellow fever, and from their infected clothes, &c. Hence it was be- lieved, that the great precaution for safety, consisted in keep- ing as remote as possible from the sick; and where this belief obtained generally, the sick were neglected and abandoned by those who entertained such views. Dr. Rush, in his zeal- ous and philanthropic labors to remove this error, frequently carried his arguments even beyond the point at which he would have rested, had such prejudice not obtained so gene- rally. He strove to convince the people, that the disease was the result of local causes and circumstances; and not pro- duced solely by the emanation from a diseased body, or from a secret contagion brought from the West Indies ; by which 12 one man was infected; to whom all other cases were to be traced. In his efforts to disabuse the public mind on this point, it was not necessary to stop and discuss the exceptions to the general rule; it was politic in him to pass them by, and direct all his efforts to establish the great fundamental truths which he was inculcating. Hence, nearly all his writ- ings go to show, that it was of domestic origin, and spread from an infected atmosphere, more or less local. It was his business to break down the general prejudice, and prepare the way for calm and impartial reasoning : this he did: and left it to his successors, and to other times, when public senti- ment should be prepared, to define the precise nature and extent of the exceptions to the general rule. It is in this track we presume to tread. In pointing a local cause suffi- cient to contaminate the air of a city, or district, it became him to urge upon them the agency of those prominent causes which they would most readily admit, until such time as more light might be let in upon the subject; and when the pre- conceived opinions of contagion might be so modified as to ensure a patient hearing and consideration. Hence he di- rected public attention especially to putrid animal and vegeta- ble matters in the city, about the wharves and shipping, and to city filth :—matters which were perceptible, and withal re- volting to their senses, and which of course would chain their attention. But now, when the barrier of error has been broken down, we may begin to examine the subject more mi- nutely, and, if possible, fix the precise limits where truth and error meet. To contribute to this end is our object, and we hope we shall be heard patiently and with a desire to arrive at truth, more than to establish or confute any particular theo- ry or set of opinions. The grand fundamental point con- tended for by Dr. Rush, is, that the yellow fever is and has often been generated by the local circumstances in our com- mercial cities. But he admits, that, under certain circum- stances, it may tend to reproduce itself. He admits that it 13 will not spread from a few cases in a pure air, and that in an impure or miasmatic air it will spread. This miasmatic air he contends is produced from animal and vegetable putrifac- tion, in certain states of weather. We also say yellow fever will spread, and become epidemic in an air strongly charged with miasm; but we ascribe the miasm to a different cause. Dr. Rush says, " yellow fever is not contagious (infec- tious ? ) in its simple state, and spreads exclusively by means of exhalations from putrid matters, which are diffused in the air. That it does not spread in the ( pure air of the) coun- try, when carried thither from cities in the United States: That it does not spread in yellow fever hospitals, when they are situated beyond the influence of the impure air in which it is generated. * * That it generally requires the co-op- eration of an exciting cause, with miasmata to produce it." Med. Repos. v. 6, p. 156, &c. In relation to yellow fever patients, confined in close, sul- try, filthy rooms, where the exhalations and excretions are suffered to accumulate, he admits it to be infectious. He says, " I have heard of two or three instances in which the yellow fever was propagated by these means, in the country, remote from the place where it originated, as well as from every external source of putrid exhalation." Ibid. p. 157. Dr. Rush says, or admits, that yellow fever maybe con- tracted by "a person sleeping in the sheets or upon a bed impregnated with the sweats and other excretions, or by being exposed to the smell (breathing?) of the foul linen or other clothing of persons who had the yellow fever." « That it was once produced in Philadelphia from the effluvia from a chest of unwashed clothes, which had belonged to one of our citizens, who had died with it in Barbadoes: but it extended no further in a large family, than to the person who opened the chest." He accounts for this happening so seldom, by "the superstitious dread of contagion, which has generally produced great care not only in washing sheets and clothes, b 14 and airing beds supposed to be infected, but frequently the total destruction of them by water or fire A Ibid. Here the most eloquent champion of the non-contagious nature of yel- low fever, and one of the most learned setiologists admits all that we contend for: that an effluvium is generated from a yel- low fever patient, which is capable, under favorable circum- stances, of reproducing that disease in those who breathe it. His explanation of the modus operandi, does not accord with our views of the subject: the fact is important. Still we do not consider it essentially a contagious disease, notwithstand- ing these facts, which our own experience and a mass of au- thority might swell to a volume: but it convinces us of the necessity of cleanliness, ventilation, and precaution. Another important fact admitted by Dr. Rush, is one fur- nished him by Dr. Otto: viz.—" In the autumn of the year 1798, it (a malignant remittent fever) prevailed upon the shores of the Delaware, in Gloucester county, New Jersey. A mild Remittent prevailed, at the same time, on the high grounds, a few miles from the river. During this time, the Doctor observed, if a person who had taken the yellow fever in Philadelphia, afterwards came into a family near the river, the same disease appeared, in several instances, in one or more branches of that family: but where persons brought the fever from the city, and went into a family on the high grounds, where the mild remittents prevailed, there was not a single instance of a yellow fever having been excited by them in any of its members." Med. Repos. v. 6, p. 160. This is an important admission, and one which every unprejudiced person, who has been conversant with yellow fever, will also admit: and in substance it is precisely what I contend for; viz: that, in an infectious air, yellow fever may spread, with- out proper care. And Dr. Rush further says, that "the city of Philadelphia has furnished, in all our yellow fever years, many additional proofs of the correctness of Dr. Otto's re- marks " What is it but personal infection, added to an infer- 15 tious state of the atmosphere? For when, as Dr. R. observes, the atmosphere is highly infectious, or "charged with the miasmatic effluvia, or ' pestilential exhalations,' a single case of yellow fever will excite it in a whole family." Ibid. p. 160. Dr. Tilton, an old physician of great celebrity, during and soon after the revolutionary war, in speaking of the yellow fever which prevailed at Wilmington, Delaware, August, 1798, says, "no one doubted it having been brought from Philadelphia, in infectious or bad air, in boats, shallops," &c. He says it began about the water's edge, and spread gradually up to the highest streets: having first appeared early in August, it became epidemic by the middle of Septem- ber.* Dr. Geo. Monroe, speaking of the same epidemic, says it was clearly traced to an infected vessel from Philadel- phia, then at the wharf, and that part of the town near the wharf suffered most severely.! The atmosphere being in a suitable condition for propagating the disease, the air from the vessels acted as a leaven. It must be borne in mind, that these facts are not adduced as evidences of contagion, nor do the persons who detail them consider them as evidences of con- tagion, but as showing clearly that the bad, infected air of ships, as well as other localities, may be so diffused about a wharf, as to produce yellow fever in those who are highly predisposed, by a strongly miasmatic or infectious atmosphere. They contend, that the infection, or infected air, of ships and other places, will diffuse itself, and produce disease in those who breathe it, provided the general atmosphere in which they live is highly morbific, or predisposing to disease, but that it will not otherwise: that when such a condition of air exists, the infection will gradually spread, and finally, without a change of weather, produce an epidemic: and that, in a healthy state of the air, this infected air, or infection, does not extend itself. I That a ship, when so infected with yellow fever miasm, maybe as much a source of miasm, or that it ' Med. Rep. vol.3, p 123-130. t Ibid, p. 136. ; Med. Kcp. vol. 3, p. LOO, 16 may be disseminated from a ship upon the contiguous popu- lation, as well as from a pile of oysters, or putrid coffee, or any other source of miasm. That this infected air from ships, in a healthy state of the atmosphere, will not produce the dis- ease in those near the wharf where it lies, unless they go on board; or it will not infect the contiguous atmosphere, unless that asmosphere be highly contaminated, and have already predisposed the population to disease. Dr. Rush, and others, who were compelled to admit these facts, affirm that this in- fected air acts only as an exciting cause; and that, in this re- spect, it sustains the same position that dissipation, exposure, fatigue, and the like, sustain to disease. We do not object to this either; but if it thus becomes an exciting cause, which is unavoidable, and produces or excites disease in those who would avoid the other exciting causes, it is certainly as much to be deprecated as if it were called by another name ; for it causes the death of those who might otherwise escape. Another great pol.rt of difference among medical men, is in relation to the source or origin of the malaria of yellow fever, as an epidemic. As to its nature or properties, as be- fore observed, we know nothing except by its effects upon the human system. It is an invisible, inodorous, aerial poison, which cannot be perceived by any of our senses; and has not been detected by any chemical analysis. Yet most men seem to look for it in the foetor which arises from the putrifaction of animal and vegetable substances: and these substances are looked upon as the only true source of the miasm of yellow fever. Hence, whenever yellow fever makes its appearance in any portion of a city, they immediately commence a search for the source of the infectious miasm : and the first matters of the animal or vegetable kingdoms, in a state of decompo- sition, with which they meet, are at once unequivocally de- clared as the source of the pestilential miasm. If nothing purely animal or vegetable be found in a state of putrifac- tion, they seize upon whatever, in their opinion, is most nearly 17 allied to them. And this continues to be the case, notwith- standing these foetid effluvia have been tested, and found to contain no principle particularly deleterious to health: each one, in reference to the cause of an epidemic, looks alone to those matters which are most offensive to their olfactories; notwithstanding experience teaches that the infected atmos- phere cannot be distinguished from common air, by any of our senses. In searching out the source of this disease, in- stead of being directed by reason and experience, it is too fre- quently the case, that they are "led by the nose" alone; and where nothing else can be found sufficient, all the pestilence is traced to a filthy back yard, a wet sewer, a dead rat, or a rotten potatoe. As we before observed, the immediate cause of yellow fever as an epidemic, is a subtle gaseous poison in the atmos- phere : but how it is generated, or from what it is thrown off, we are not certainly informed. The medical faculty have been constantly engaged in efforts to detect its origin and ex- plain its nature; they have manifested zeal and industry worthy the cause of science, to search out and expound the hidden, if not mysterious cause. In unnumbered instances, they have supposed they had traced the monster to his den : but when they have attempted to place the shackles upon him, he has vanished. The difficulty of arriving at the true knowledge of such a mysterious agent, has only stimulated the zeal, and excited the industry of the medical faculty, whose province is to search out the physical causes of morbid phenomena. Hence the great diversity of opinions entertained and ad- vanced on the origin of this pestilential miasm. At onetime, it has been traced successfully, as was believed, to putrefying and putrid vegetable matter, sometimes of one kind, and some- times of another. At another time, it has been as clearly traced to putrescent animal matters of one kind or another: at another time, it has been as clearly traced to the union.of animal and vegetable matter in a state of putrefaction; at an- 18 other time, it has been traced as clearly to a source dirfeiing widely from either, and apparently entirely independent of all of them; at another time, it has been tractd to some at- mospheric phenomena, independent of any cause under our control; at another time, it has been traced to increased and continued temperature of the seasons; at another to vicissi- tudes of weather, which were perceptible to our senses, as changes from heat to cold and rice versa; and, at another time, to changes of which we can form no definite idea, such as a mysterious epidemic constitution of the atmosphere. Oth- er circumstances, again, have carried, as was believed, incon- testible evidence that it has originated from personal contagion alone ; others, again, seem to show, that personal contagion has no agency in the matter, but that it is a poisonous air gen- erated in ships at sea, with or without putrescency. In every instance, the facts and arguments arrayed to sustain one theo- ry, have militated equally against all others; and thus of each in turn; so that nearly every theory is opposed, if not contro- verted by all the others: and whatever ground is taken, there is ten to one against it. Under these circumstances, Ave must take a middle course; for, although it is not probable that all are true in the whole, it is equally improbable that all should be entirely erroneous. All these different circumstances or relations may have had some agency, at different times, in modifying the action of the poisonous miasm: although all of them certainly could not have been actual sources for its pro- duction. Some of these circumstances may have increased or diminished the susceptibility of the system to its action, or so modified it as to render its effects apparently more or less direct from the efficient malaria. Great solar heat is one circumstance which invariably pre- cedes, and is certainly an essential requisite to generate the miasm or infection of yellow fever; and the fact that the ab- sence of heat, or cold, as invariably destroys it, shows that its production is effected by some unknown combination of solar 19 heat, with some unknown principle in the atmosphere; and we infer that the numerous other sources to which it has been ascribed, have had their agency only in modifying the effects of this poison on the human system. To enter into a detailed explanation of the manner in which these various causes may effect the susceptibility of the system, is beyond our present purpose. We will only remark briefly on some of the most prominent theories, in relation to the source and production of this miasm, or malarious poison. Those who contend for its origin in vegetable putrefactions have ascribed it to putrid coffee, to putrid potatoes, to putrid oranges, to rotten corn, to putrid sour crout, sour porter, and the like; in warehouses, on board ships, or lying exposed upon the wharves. Those who believe it originates from animal putrefaction, have ascribed it to the opening of old burial gronnds, to pu- trid fish, to putrid bacon, to putrid pork, to putrid animal car- cases, to putrid hides, to putrid oysters, and to similar matters discovered about the wharves and shipping, or in other parts of cities. Those who contend for its origin in effluvia generated by the sun from the surface of the earth, have ascribed it to exha- lations from stagnant water in marshes; to the exhalations of marshy ground, when all moisture is evaporated; to exhala- tions thrown off by loose earth exposed to the sun; to exhala- tions thrown off by mud, and common city filth, in sewers and back yards; and, Avhen these are wanting, to any thing their fancy may suggest. Those who believe it to originate in sensible changes of the atmosphere, have ascribed it to a dry, heated air; to moist hcatedair; to a continued mean temperature at or above 80° for forty days togethei ; to suddrn \icisiitudes from hot to cool weather, and the reverse ; to the absence or presence of much electricity in the atmosphere, and absence of thunder, &c; others ascribe it to a peculiar insensible " epidemic constitu- tion" of the atmosphere. 20 To nearly all of these causes have the yellow fevers of Natchez been ascribed, by the advocates of those different theories; and each have adduced certain facts to sustain thcr opinions. Upon each of which we shall make a few remarks, and pass on to the history of the epidemics of Natchez. 1st. Of animal putrefaction. Dr. Bancroft, in his work on yellow fever, to prepare the way for establishing his theo- ry of marsh-miasm, has adduced an array of facts and evi- dence incontrovertible, proving that animal putrefaction may exist to any extent, and under all circumstances, without pro- ducing yellow fever; and consequently, that it is not a neces- sary source of the miasm; and that, of course, yellow fever miasm is, or may be, produced from some other cause. He has shown, that this kind of putrefaction, is not even a fre- quent concurring circumstance; and that animal putrefaction has existed in cities, and other localities, under the most favor- able circumstances for its production, according to that doc- trine, Avithout having produced yelloAv fever, either epidemic- ally or sporadically. He has shoAvn conclusively, that pu- trid pork, putrid bacon, putrid fish, &c, fresh or salted, will not generate this miasm; nor will dead bodies of any kind, without salt, in a putrescent state, produce it; not even the pu- trefaction of human bodies, by hundreds, upon the burning sar.ds and marshes of Egypt; nor is it produced by the intol- erable stench produced and kept up by animal matters in cities, or about factories of glue and catgut; about butcheries, tanneries, chandleries, &c. These facts, Avhich are incontro- vertible, all confirm the opinion sanctioned by experience, that the miasm or infection of yelloAv fever, be it what it may, is not, in any sense, dependent upon, or connected with the fator of animal putrefaction, either in its incipient state, or in a state of complete decomposition. It has been placed beyond doubt, that the miasm, or infection of yellow fever, has been generated abundantly in the holds of ships at sea, where no putrid animal or vegetable matters have existed; a good ex- 2' ample of this kind is found in the United States brig " Enter- prise," hereafter referred to. There are cities or towns in the tropics, where abundance of putrid animal and vegetable matters are combined with effluvia from mud and marshy bot- toms of shallow harbors, and yet they enjoy uninterrupted health: an example of this kind is found in the town of Cam- peac hey hereafter cited. 2d. Of vegetable putrefaction. That this is not the es- sential cause of yellow fever miasm, is proved by the same array of facts and arguments which are brought against that of animal putrefaction. Vegetable putrefaction "of the most offensive kind, and in the most extensive degrees, have oc- curred, without producing a single case of yelloAv feA-er in those frequenting them ; and the most devastating epidemics have prevailed, where no mass of vegetable putrefaction could be detected, In our own neighborhoods, how often do we find cotton seed in a rotten state, to the amount of several hundred bushels together, with a stench almost intolerable, Avhere no fever of any kind, much less yelloAv fever, is pro- duced on the plantations? During the hot weather of sum- mer, this is a common occurrence; yet, in no instance has it produced yellow fever among the swarms of negroes, and often white men, Avho are daily about them. In the last epi- demic of Natchez, no masses of vegetable putrefaction were even suspected. When vegetable putrefaction or decomposi tion is carried on most rapidly, or in seasons Avith regular vicissitudes of rain and sunshine, .there is no yelloio fever: but it makes its appearance often when all moisture is dissi- pated from the face of the ground; and when the process of vegetable decomposition, must have entirely ceased, for want of moisture. The whole weight of testimony is against the probability of vegetable putrefaction being an active cause. 3, Of marsh miasm. Dr. Bancroft has labored much to prove that this is the true cause of yellow fever; but his labors on that point have all been in vain. We find this dis- 22 ease prevailing equally in the vicinity of marshes, and on the dry and barren rock, where no marsh is near. We find it equally prevalent on high and on low situations; upon the high bluff at Natchez, and on the still more elevated hills of Washington, as well as in the low marshes of Charleston and the quagmires of New Orleans; upon the sandy beaches of Pensacola and Mobile, and upon the rocks of Lisbon, Cadiz, and Gibraltar: we find it equally in the alluvial delta of the Mississippi and Orinoco, and upon the sterile shores of Curra- coa, where marshes are unknown. On the other hand, in many alluvial and marshy regions on the loAver Mississippi and elseAvhere, which ought to be most favorable to the pro- duction of marsh-miasm, yellow fever is unknown. In the West Indies, where it is endemic all the year, it prevails alike on the fertile, and on the barren shores; but it is unknown in the interior. 4th. Arid and humid atmosphere are alike non-essential to its production. For, under every variety of aridity or humidity of the atmosphere, has it appeared in our own coun- try, as Avell as elsewhere. It has made its first appearance in New Orleans as an epidemic, in cloudy, damp, and Avet weather; it has appeared there also in the driest Avea- ther ; it has appeared also in other southern ports, in dry and in humid weather; after a wet and a dry spring; after a warm and a cool spring; it has prevailed at Natchez, after a Avet and a dry summer; and, again, when the same months have not been either unusually Avet or dry. It prevails in commercial places, equally where the air is habitually humid, and Avhere it is habitually arid: no less in Charleston and New Orleans, than on the parched shores of Curracoa. Dr. Peixotto informs us, that the yellow fever is endemial in the island of Curracoa at all times and seasons, but it occurs more especially in the calm and sultry months of the year. New comers from northern latitudes are its appropriate* sub- jects : the natives and seasoned inhabitants being exempt from 23 its attacks." * On this island, it becomes epidemic only when large numbers of northern strangers arrive during the sultry months of the year. Yet the air of this island is proveibial for its dry, elastic qualities. Dr. P. informs us, " The air is pure and dry, and seldom or never darkened with mists and fogs, so frequent at the north. * * * During the droughts, which are common, the leafless desolation of winter reigns under a tropical sun: ordinary wells are exhausted; animate and inanimate nature suffers under the burden, and seems nearly ready to waste away and perish." f On this island, there is no marsh, or scarcely a stream of fresh water. 5th. Sensible changes of temperature, alone, have no ma- terial influence over the generation, or accumulation of this miasm. The general views, entertained by those Avho advo- cate the theory that a certain unremitted mean temperature is thechief cause of yellow fever, is embraced in Dr. Caldwell's "Dissertation upon Yellow Fever;";): viz. that whenever the mean heat or temperature is steadily up to 80° Fahrenheit, or above, for forty days or more in succession, yellow fever will be produced; but if the same mean temperature be main- tained for only twenty, thirty, or even thirty-five days, there will be no yellow fever, provided there be no "epidemic con- stitution in the atmosphere," which he has not explained. This, at first sight, might appear plausible; but facts com- pletely confute the arguments. We need not go further than to our own city for the facts. Aceording to a meteorological table given by Dr. Perlee, || the mean temperature of July and August, for sixty-two days, in 1814, 1816, and 1818, Avas steadily from 80° to 83,° yet no yellow fever occurred in Nat- chez in either year. In 1817, the mean temperature of July was 80° for thirty-one days, and August 77° for thirty-one days, giving a mean temperature of 78|° for sixty-tAvo days ' New York, Med. and Phys. Jour. vol. 1, p. 411, 412' t Ibidem, p. 398, 400. ;Soe Med. and Phys. Memoirs, Lexington, 1826, p. 141,'J. A.c. I Chapman's Med and Phys. J. v. 3, p. 17. 21 and yet the yellow fever prevailed malignantly. In 1819, the mean temperature of both July and August, sixty-two days, was up to only 79° each month, and the mean of Sep- tember for thirty days, was 75,° and yet the yellow fever pre- vailed with great mortality, having become epidemic on the 14th of September. We might cite authority without end, to show the same facts in other places every year; but we will adduce only one more from Natchez, as obtained from the tables of Dr. Tooley and others. In 1824, the mean tem- perature of July was 86° for thirty-one days; of August, 82£° for thirty-one days : together sixty-two days, averaging 84,° and yet no yellow fever occurred in Natchez that year.* In 1825, the mean temperature of July was 81° for thirty-one days; and of August 83^° for thirty-one days: averaging 82° for the whole, or 2° less than 1824, yet the yellow fever prevailed with great mortality. If the miasm of yellow fever Avere the result of any change of moisture, or of tempera- ture solely, which the thermometer would indicate, then we might avert it by Avatering the streets, to reduce the tempera- ture : or, at least, we might be able to foretel its appearance, and escape in time. But this has not yet been done. There is, doubtless, more or less of a general " epidemic constitution of the atmosphere" existing at certain times, over an extensive scope of country. This peculiar state of the atmosphere, aviII doubtless predispose the inhabitants to dis- eases of a certain type, and they will be afflicted epidemically, Avhere the particular locality is favorable, and the requisite exciting causes are brought into action. But as regards yel- low fever, we believe the peculiar condition of the general atmosphere, which precedes it, can be observed, and guarded against, by proper and timely precaution, and the avoiding and removing what are admitted to be exciting causes. This in July • 9 days in August, and 5 in Sent " 11 «« « 5 » 25 " epidemic constitution of the air," can be nothing else than the to Qiov of Hippocrates; or the " seminarium e codo di- missum" of Diemerbrceck, if it be not from some physical cause; and the present state of medical science is such, that we are not satisfied with an explanation which implies mystery. Whether yellow fever infection can be imported, and dis- seminated in an impure air, is a point upon which there is less difference of opinion, than upon the origin of the miasm : for, although many contend for its local origin, and the non- contagious character of the disease, yet there are but few who cannot perceive, and must admit, that when the miasm, or in- fection, is once generated abundantly, it may be introduced into impure air, and there spread the disease. But few re- main Avho are not able to perceive,that persons maybe infect- ed Avith yellow fever, who sleep in beds or blankets, taken from highly infected air, or Avhich have likewise been used as the death-bed of yellow fever patients. As we have said that yellow fever is a commercial disease, we will show to what extent it is so, and in what manner it obtains that character. In our citation of authority, we have been careful to depend upon those who range themselves as the advocates of the domestic origin of the disease, and not upon those Avho have been steeped in the doctrine of conta- gion. This fact, we hope, will give due weight to the au- thority which we adduce. All testimony tends conclusively to establish the point, that ships which have been long at sea in tropical latitudes, have occasionally become thoroughly infected with yellow fever miasm or infection, either Avhile at sea, or while in port: and that this infection has occasionally been so concentrated as to have produced yellow fever in its most aggravated form, in those who have gone on board from shore; and that such persons have taken the yellow fever, and died of it in from five to ten days after they breathed the infected air of the ship; although, at that time, none of the sailors or hands on c 26 the ship, were laboring under that disease. In this manner doubtless, in some instances, has yelloAv fever begun to pre- vail in sea-ports, among the many Avho daily, unconscious ol the infection, visit such ships Avhile in port. In this manner, in many instances, have the first twenty or thirty cases been traced to intercourse with an infected ship, or to goods from the same. These first cases are generally persons near the wharves, draymen, day-laborers, and others Avho are engaged in assisting to unload the cargo. It is perfectly immaterial Avhether the ship brought the infection from a foreign port, or generated it during her voyage. If the air in her hold can be disseminated about the Avharf, or even if it will cause those who visit the ship to die of yellow fever, it certainly is an imported disease to those Avho suffer. A ship can certainly become infected, and much more com- pletely than a house, or a district of a city. On shipboard, the air below is necessarily close for Avant of ventilation.— We will not travel over all the mass of testimony Avhich might be adduced : but will cite only a feAv instances in our own country, which are conclusive : for one unquestionable case, is as amply illustrative of the principle, as tAventy. Dr. Tully,* one of the most scientific physicians of Con- necticut, gives an account of a number of cases of yellow fever at Knowles' Landing, in August, 1796. This is a A-il- lageon the Connecticut river, about six miles below Middle- town, containing a population of about two hundred souls, and situated on a steep declivity, Avith spacious and airy streets, and not crowded Avith houses. The number of cases that occurred at this place was eleven, of whom nine died. Every case was clearly traced to communication with a vessel which had recently airived from Havana, on board which one of the sailors had died with yellow fever on the voyage. The Avhole number of cases occurred and terminated in the course of a fortnight; for the alarm excited by the appearance of ' See Med. and Phys. Jour, of New York, vol. 1, p. 153-8 27 a malignant disease among them, caused a complete and speedy desertion of the village, and non-intercourse with the ship. This village has always maintained the character of uncommon salubrity. Up to the arrival of the infected ship, no disease of any kind prevailed; and immediately the ship was abandoned by the inhabitants, the disease ceased. The infection on board this ship was not generated by putrefaction of either animal or vegetable matters, as none existed on board; and Dr. Tully declares that she Avas perfectly clean; no such matters were found in the town, or suspected by any as the cause of the disease: the ship was the undoubted source, and none were attacked but such as had been on board. In this case had the Aveather been such as generally precedes epidemic yelloAv fever: and had the inhabitants not fled, but remained, and continued their intercourse with the infected ship, the town would doubtless have been visited with epidemic yellow fever. Dr. Tully informs us, that as many other cases occurred at the different places at which this vessel anchored in ascend- ing the river, and always in those only who had been on board. He also informs us, that, for 'the last twenty-five years, scarcely a year has passed, in which one or more simi- lar cases have not appeared at different points on the Connec ticut river; all of which are clearly attributable solely to in- tercourse with vessels from the West Indies, or from southern ports of the United States. Dr. Bay ley,* health officer of the port of New York, gives an account of a number of cases of yellow fever Avhich occurred, in the autumn of 1821, at the "quarantine estab- lishment," on Staten Island, six miles below the city. From the 8th of September until the 7th of October, twenty-nine cases and twenty-one deaths occurred ; of the latter, fourteen had black vomit. These cases were clearly traced to inter- course Avith infected vessels then lying at the wharf, and re- ' New York Med. and Phys. Jour. vol. 1, p. 27, 28,&c. 28 cently from the West Indies and NeAV Orleans. The health of those about the " quarantine establishment" never A\as better, both immediately before and after these cases : nothing like bilious or remittent fever had been seen: neither marsh- es, nor filth, nor vegetable putrefaction existed any Avhere in the vicinity. The cases were traced clearly to the ships, and to them alone: and each case occurred just five days, and one on the sixth day, after the particular exposure to the in- fected air of the vessels. A Avashenvoman and her two daughters, took the disease, without having been on board the vessels. They contracted their disease by handling and wash- ing the foul clothes and bedding of four men who had died of yelloAv fever about four days previously. The bedding and clothes had been throAvn aside until taken to her to be washed. She took the disease just five days after she had handled the clothes, and died on the fifth day of her disease; her daughters were attacked afterwards. In this case, a fa- vorable condition of the air would, no doubt, have caused it to become epidemic. Dr. Bayley * also gives us the case of the United States' brig Enterprise, infected with yellow fever, at the " quaran^ tine ground," in 1822. This vessel Avas perfectly clean, and free from any animal or vegetable putrefaction. She arrived from Havana with ten cases on board; and immediately the sick were removed to the hospital, and the well were quar- tered on shore, to avoir! the infected air of the vessel. She was then thoroughly cleansed, ventilated, washed, and white- washed with lime, in a tenfold degree; lime was slalcd in her timbers in large quantities. Yet, after this purification, she retained the infection, and communicated the yellow fever to those who afterwards went on board; of whom five, out of eleven, died. The process of purification was again insti- tuted. Artificial ventilation Avith windsails was constantly performed; water, to the depth of several feet, Avas daily let ' New York Med. and Phys. Jour,, vol. 1, p. 4215-7 .Scc. 29 in, and pumped out: lime A\ras streAved in the hold, and her timbers thoroughly whitewashed, and still the infection was not destroyed, until cold weather. In this case, her own crew having taken the disease first, the people from shore avoided the vessel, and escaped the disease. Another case is given by Dr. Kollock, and quoted by Dr. flush, in Avhich a vessel at sea, in tropical latitudes, engen- dered on board a malaria Avhich finally produced yellow fever. This is the case of the United States' frigate General Greene, which became infected Avhile on a cruise in the West India seas, and did not become disinfected until she reached the cold climate of Rhode Island. During the time, she retain- ed the infection, every kind of cleansing, fumigation, and ven- tilation, were used freely, but ineffectually. In this case, the vessel was new, and perfectly clean and healthy, Avhen she left Newport, Rhode Island, on the 3d of June, 1799. She had on board a complement of two hundred and fourteen souls, besides large quantities of provisions for a cruise in the West India seas. Having encountered a storm, soon after she put to sea, the Aessel became leaky, and a noxious mala- ria was generated, during a subsequent period of unusually hot weather. At first, and for some days, the disease assumed the symptoms of a violent bilious fever, Avith no deaths until they arrived in the port of Havana; when immediately seve- ral cases began to assume symptoms of yellow fever. " After this period," says Dr. Kollock, "three, four, and five new cases occurred daily; and the violence of the symptoms seemed to increase with the multiplication of cases, during the six days she lay in port." f Cases and deaths continued to multiply daily, until she passed the capes of Virginia, when the disease became gradually milder. The whole number of the cases was forty; and twenty of them died. In this case, an infectious air was generated in the ship's hold, by the num- ber on board, during the hot weather and leaky condition of t Med. Rep. vol. 4, p. 3. C* 30 the vessel; and it appears that the " leaven" of infection was superadded at the port of Havana, either by persons going on shore, and contracting the disease there, or by the introduc- tion of infected air, &c. Many other cases might be cited, in which infection has been generated and carried in ships into ports, and there produced yelloAv fever in those from shore who entered on board, although the creAV of the vessel, being acclimated, remained free from disease. The only point remaining, to establish the importability of epidemic yellow fever in ports, is whether the dissemination of the infected air of the ship in the vicinity of the wharf, among the crowds that frequent them, and reside near them, together with ten, twenty, thirty, or more cases, which were contracted by going on board such vessels, be capable of causing the disease to spread, among those contiguous, who do not go on board, and this when the temperature of the season, and the sultry, and if desired, the miasmatic state of the air, is in the most favorable condition for disseminating the disease. Of this, we think there can be no reasonable doubt. Dr. Rush, and his coadjutors in favor of the domestic origin of yellow fever, admitted that^it might, and had occasionally, spread from ships in an impure air. Dr. Mitchell,* one of the most able advocates of the local or domestic origin of yellow fever, in a report made to Con- gress, February 25th, 1803, admits, and even contends that vessels oftenbecome highly infected, while at sea-, that an im- pure air is generated in the holds during hot, sultry weather, in tropical climates: that this infection may be communicated not only to those who go on board, but that the infected air may be diffused in the atmosphere about the Avharves and shipping, and thus excite the disease more generally. He contends, very properly, against useless and idle detention at quarantine, when no disease or infection has been on board the vessel; but he urges the necessity of detention, and tho- ' See Med. Kepos. vol. 6, p. 460, A:c. 31 rough ventilation and cleansing, in case of infection, until the infection is destroyed. In all this he denies the foreign origin of infection. But is it not immaterial to those in sea port towns, whether the infection be generated on board, or con- tracted in a foreign port? If it can spread among those where the ship arrives, it is as important to guard against it as if it were of foreign origin. Dr. Rush unequivocally admits that there is much danger to be apprehended from "the foul air of ships," Avhere cases of yellow fever have oc- curred. He also admonishes us, "to prevent the landing of persons affected with the ship fever, in our cities, and the more dangerous practice of ships pouring streams of pestilential air from their holds upon the citizens, toho live near the docks and wharves." Med. Rep. vol. 6, p. 166. Again, in a communication from Dr. Rush and others to Gov. Mifflin, in relation to the yellow fever of 1797, in Phila- delphia and Kensington, it is maintained, "that, in addition to the filth and putrefaction about the city, the foul air issuing from the holds of tAvo ships, (designated,) produced the yellow fever, independently of foreign contagion." Again, the au- thors declare, that " the close, unventilated holds of ships, after long voyages in hot climates, with perishable matters on board, thrown open in a heated, sultry atmosphere, are a fruitful source of miasm: although they infer, that " yellow fever has not been so often propagated by contagion, as has been supposed." See Med. Repos. vol. 2, p. 95, 96. Without multiplying authority, we will cite one case which is full of instruction to those who preside over the port police of our cities. We mean the " Yellow Fever " of New York in the summer and fall of 1822. This epidemic, if it could be so called, commenced by scattering cases from the 15th to the 20th of July, and cases multiplied gradually until the 15th of August, when it Avas considered epidemic. The whole number of yelloAv fever cases, from the I5th of July until the 1st of N®Arember, Avhen it ceased, was about four hundred and thirty, of whom about two hundred and fifty died. It began in Rector street, near the wharf, where four ships' cargoes had been discharged from infected vessels, a feAV days before. From this point, it spread very slowly over several squares in the vicinity, having extended only a few squares in thirty days: while the remainder of the city was unusually healthy. The squares over which it prevailed most fatally, Avere bounded by Avide, clean, and airy streets, and the most substantial buildings in the city: no filth could be found in the vicinity; the infected air from the original in- fected point having been wafted thither by the winds. These are the facts without speculation ; viz : the first cases began betvveen the I5th, and 20th of July. Between the 1st and the 9th of July, the cargoes of four infected vessels from Havana, were discharged at the Avharf at the foot of Rector street, and stored in Avarehouses. Two of these ves- sels had lost some of their crews by yellow fever, on the voy- age; the crews of the other two were Spaniards and accli- mated sailors. During the first two weeks of July, the wea- ther was very warm, the sun cloudless, and the air "very calm and sultry." During the months of July and August, there were almost daily arrivals of other vessels from Ha- vana, and other ports where yellow fever Avas known to be prevailing. During this period, the number of vessels from West India ports Avas unusual; because, on account of the terror of pirates, they came in companies, under the convoy of battle ships. The following are the arrivals at the quar- antine ground, between the 11th of June, and the 17th of Oc- tober ; viz: From Havana, eleven vessels, having, or having had on board, forty-four cases of yelloAv fever and twenty-one deaths; from Matanzas, one vessel, with three cases of yellow fever; from St. Jago, two vessels, having had three deaths from yellow fever ; from Port au Prince, St. Domingo, four vessels, with six deaths from yellow fever : from Vera Cruz between July 17th and 28th, three vessels, with nineteen 33 cases and tAvo deaths from yellow fever, before arrival. Be- sides these, there were, during that time, about forty other vessels from southern and West India ports, whose crews, be- ing Spaniards or acclimated seamen, had no cases during their voyage, although the air in some of the vessels proved infec- tious to those who were unacclimated. If any one -will take the pains to examine the accounts of this epidemic, as detailed by Dr. Townsend,* Dr. Bayley, and Dr. Walters, and after making every alloAvance, especially to Dr. Townsend for his vievvs of contagion, of that charity Avhich the advocates of the exclusive local origin of yellow fever are so ready to bestow, he will find ample reason toaura:f; that the atmosphere about the wharves was contaminated by the infectious air imported in ships from tropical cli- mates. To'those who are at all conversant with the history of nau- tical diseases in hot climates, it cannot be a matter of doubt, that vessels frequently become infected, Avhile cruising in trop- ical seas, and lying in tropical ports, and the sailors and pas- sengers, especially when they are unacclimated natives of northern latitudes, will sicken and die. An infected air also accumulates gradually, in some manner, in the holds, which Avill infect strangers, although the crew may not suffer.— When large quantities of this air is brought into our ports- in hot, sultry weather, as was the case at New York in 1822, it will certainly infect the contiguous local atmosphere; or act as a morbific "leaven" to it, just as the infected air of an "infected district" gradually extends itself over other parts of a city. It does not change the nature of the case, whether the injected air depend, in any degree, upon personal " conta- gion." But if the yelloAv fever, as an epidemic, depend sole- ly upon "an epidemic constitution of the atmosphere," Ave would inquire, why it does not affect every part of a city in- discriminately, and not that part only near the shipping? ' See Townsend on Yellow Fever of New York, in 1822. 34 If any one admits that the air of a city can be infected from a pile of putrid matters or filth, why can he not perceive that it can be much more readily infected from a source where the infection is completely formed, and virulent, and only requires diffusion in the air? Let not the specious term "contagion," mislead. If these sources of miasm or infection be capable of excit- ing yellow fever in those persons who reside near the land- ings, although highly predisposed by the impure air of the city, but Avho might otherwise escape, it is but poor consola- tion to be informed, that it is not " contagion," or that the in- fection is not brought from a. foreign port. To them it is im- ported, although it may have been generated only three days- or twenty-four hours before the ship arrived in port. If only the exciting cause is thus imported, would not all cities do well to prohibit the introduction of this exciting cause? We have said yellow fever is a commercial disease; and that it prevails mostly in ports which carry on extensive trade with tropical countries or ports. Those towns and cities which do not carry on such commerce, are mostly exempt from yellow fever, although in the same latitude with those afflicted by that disease, and under the same general circum- stances. To say the least, they are exempt from the excitin"- cause, whether it be infected air from ships, or the simple fa- tigue and exposure of seamen about the ships. In certain years, a general predisposition exists, as the effect or result of continued hot, sultry weather, from New York, or even from Boston, along the whole sea-board, to New Orleans.__ This general predisposition, which may, however, vary in degree at different places, finally, in most places, passes off without any epidemic yellow fever, except in a few towns or poits, which, have fine deep harbors, and enjoy extensi\'e com- merce with tropical countries. In others not possessing these advantages, it does not prevail. Hence Ave find it pre- vails in Philadelphia, New York, Baltimore, Norfolk 35 Charleston, Mobile, and NeAv Orleans; but Avhy does it not prevail, at the same time, in Harrisburg, at Troy, at Washing- ton City, at Richmond, at Columbia, at Oppelousas, at Tusca- loosa, and other inland to\Arns? The same general predispo- sition, or " epidemic constitution of the air," exists in all these places; but only a feAv of them are exposed to the " exciting cause, necessary to produce an epidemic:—the "leaven" from the infected air of ships, or goods from infected places, are wanting to complete the train. Those towns that are destitute of these, avoid the pestilence. Sporadic cases may occur from high exciting causes of another kind, but in a free, pure air, it passes off Avithout exciting other cases. A case presents directly in point, on this subject, as well as in relation to the agency of putrid exhalations and marsh miasm in the production of yelloAv feA'er. The town of Cam- peachey is situated on the Gulf of Mexico, in latitude 19° 45' N.—Vera Cruz is situated about three hundred and fifty miles distant, but in about the same latitude. Campeacheyis healthy, and Vera Cruz is visited annually with yellow fever. The circumstances generally considered most favorable to the production of yellow fever, are equal in both places. Cam- peachey is built mostly of stone, upon a substratum of lime- stone rock; the soil of the surrounding country, as well as a part of the town, is a sandy loam, and often becomes very muddy; the town is surrounded by a stone Avail about ten feet high; the streets are wide; the houses are large and airy; on the back part of the toAvn, there is a high hill, or moderate mountain, which greatly interrupts ventilation, so that the inhabitants suffer greatly, from " all the inconve- niences of a sultry, confined air." "In front of the middle of the city, is a large wharf or mole, extending one hundred yards into the water. Along this mole, there is constantly deposited large quantities of filth of every kind, together with ■■ large quantities of putrid fish. " " When the tide, (which rises and falls two or three feet,) retires, all these matters are 36 left exposed in the mud, and on the shore, to the direct rays ot a vertical sun, until the stench is intolerable to strangers. Besides these things, there are also other "accumulations of filth in other parts of the town." Yet "the inhabitants are very healthy " : there is only one physician in the place, and he has not half employment in his profession, although " the population is about ten thousand." See Med. Rep. vol. 4, p. 5-8. Vera Cruz is situated upon a sandy plain, with sand hills in its rear; contains no more filth than Campeachey; the air is no more confined or sultry ; the inhabitants are no less temperate; yet Campeachey is healthy, and Vera Cruz is annually visited with yelloAv fever of the most malignant type. See Med. Repos., vol. 4, p. 7 and 8 : also, vol. 3, p. 46, &c. A. D. 1800. How is this paradox explained?—Campeachey has an ex- tensive, but shallow harbor, so that large ships cannot ap- proach near the town; only boats and small craft can enter the harbor, such as do not exceed fifteen or twenty tons.— Hence, so far as commerce with remote regions, and the foul air of large ships, from long tropical voyages, are concerned, it is equivalent to an inland town: and it is also free from the croAvds of strangers, who infest large commercial ports. But Vera Cruz carries on an extensive commerce, has a fine deep harbor, and thus does not lack for infected air from ships, and crowds of strangers upon Avhom it operates. These, Avhen attacked, contribute to the infection, which is like " leaven" in the contaminated atmosphere, and assists in producino- the epidemics. Ibid, p. 78. Although the yellow fever is endemial all the year in Cu- ba, it is almost exclusively confined to the commercial ports. The elevated savannas of the interior are as much a stranger to it, as our own interior towns. In the ports, it attacks prin cipally strangers, and prevails mostly from the beginning of July to the middle of November. When there is a great in- flux of strangers, it becomes more malignant, and finally at- 37 tacks many of the acclimated inhabitants, especially such as are exposed to the ordinary exciting causes of fevers. It is believed, among the people of Cuba, that the influx of stran- gers, and their numerous attacks from yellow fever, contami- nates the air, or infects it, and causes it sometimes to become epidemic, Avhen otherwise it would not have prevailed. To produce yellow fever as an epidemic in our cities, we conceive three grades or stages of action in the production of the infection:—first, the miasm, or simple basis, which alone is innocent. 2d. Its combination Avith impure, or ex- hausted air, or with air deprived of its healthy, respiratory properties, and charged with animal exhalations:—in this state, Ave call it infectious air, or malaria. In this state, it is a strong predisposing cause of disease, and a suitable "nidus" for the reception and extension of personal infection. 3d, Infection, or the union of personal infection with infectious air, or malaria. In this state, it is an aerial ferment; and, when respired, becomes the active, predisposing, and exciting cause of yellow fever. These views we will further illustrate: I. The Miasm of Yellow Fever.—This we consi- der as a subtile, gaseous, invisible, and inodorous matter, gen- erated by the action of the sun, or by solar heat, upon the atmo- sphere, independently of any effluvia or foetor from the decom- position of animal matters, and independently of any exhala- tions from marshes, dry earth, or vegeto-animal compounds, or any thing of those kinds. We believe it to be the result of some unknown combination of the solar rays, with the atmosphere, which takes place at all times and in all places, while the tem- perature in the shade is steadily between 83Q and 98° of Fah- renheit, or between 110° and 130° in the open sun : that its specific gravity is much greater than that of common air, and that it possesses the common properties of aerial fluids. We think it probable, that, in its simple state of miasm, it is innoc- uous ; but becomes morbific by combination with impure air; that commonly it becomes separated from pure air, and settles 38 near the ground; that it is partially neutralized by a temper- ature of 55° or 60°; and is entirely destroyed by a tempera- ture of 50° or 45° at the lowest. The degree of its morbific qualities depends upon the nature and degree of combination. Hence, in our opinion, it can accumulate in dangerous quantities only when the vveather is steadily betvveen 88° and 98° during the day, and above 60° or 70Q at night, and du- ring a period Avhen there is but little Avind to disperse it, or only sufficient to waft it gently in the air, and cause it to settle in low confined places, in a manner similar to the collections of carbonic acid gas. We think, unless the weather is un- usually calm and sultry, or remarkably warm, to cause its rapid formation, that it requires from ten to fifteen days for it to accumulate sufficiently to be in anywise prejudicial; that strong winds sweep it away, or diffuse it in the general air; and heavy rains wash it partly off or cause it to settle in low, damp places, and deep bayoux; where, in a long succeeding calm, hot period of weather, it will accumulate until they overflow, and spread it over the surrounding grounds near their margins : that it assumes a level surface, like water, and hence is deeper in some points than at others, in proportion to their relative elevation : that it cannot accumulate on steep de- clivities without a barrier below, when it rises only to the level of the barrier. On perfectly level surfaces, it seldom raises its surface more than three or four feet above the ground, and most commonly not more than two or three feet. A cold night, with a temperature beloAv 50°, Avould destroy all that had previously generated; a strong Avind or tornado Avould sweep it out from bayoux, ravines, or Ioav confined places. Hot weather favors its formation; calm weather favors its accumulation, as well as the contamination of the air requi- site to form a morbific union with the miasm. We believe it requires for its formation an extreme tempera- ture above 88°, because unless the temperature has been up to that point during the hottest period of the day, for many 39 days, no yellow fever has occurred; whereas, although the temperature of the nights may have been up to 808 or above, so that the mean temperature is 80° or 82°, yet if the great- est heat of the day has not been up to 88? at least, there is no yellow fever. Again, a few days may give an extreme temperature of 90° or 95°; yet if one or two cool nights, at a temperature of 50° or 55° succeed, there will be no yelloAv fever for ten days subsequently at least. Again, there might be thirty days in succession, with an extreme temperature as high as 93° or 95°, and yet two cold nights, ten or fifteen days apart, would neutralize all the miasm previously formed; and although the mean heat, for a month or longer, might average more than 80°, there would be no yellow fever. Hence the mean heat should not be taken into our estimates; but the actual temperature by day and by night. The winds may be fresh from the south, so as not to reduce the temperature below 90Q by day, and yet they may carry off all the miasm, or all the contaminated air: or a calm, hot day, may be suc- ceeded by a gale at night, which will carry off the miasm. This miasm is not injured or neutralized by damp air: on the contrary if calm, damp, foggy, cloudy, or misty Aveather, succeed many days of intensely hot and sultry weather, the miasm previously formed, remains, if it does not accumulate; damp, moist air is congenial to it, and seems to attract it: or it settles over low, damp places, in preference to dry ones of the same elevation. Hence it accumulates in deep ravines or bayoux. Upon these principles, we perceive why yellow fever is most prevalent in low, damp sections of cities, near the wharves and about the shipping. These places attract and retain the miasm already formed: as well as favor its generation and preservation. The temperature about such places, from their exposed situation, is often at least two or three degrees higher than in other parts of the city. The reflection from the water adds to this effect by day, and mode- rates the cold by night. The temperature of the country air 40 is generally at least two or three degrees less than it is in any closely built parts of cities, not only during the day, but at night; country air is necessarily much cooler, because there is not such an accumulation of heat in radiating bodies. Although it requires a temperature above 88° to generate miasm, we find that it requires a reduction of nearly one-half to neutralize or destroy it. Hence yellow fever is often en- demic all the year in the West Indies; for there the tempera- ture of the air is seldom beloAv 55? of Fahrenheit, and where infection exists, even that temperature will not destroy it. These facts may be illustrated by sirriilar ones in relation to another fluid. Thus water, for example, under the common atmospheric pressure, will not boil at 200° or 205° Fahren- heit; but it will boil at 212°. At the latter temperature it passes off rapidly into vapor; and a much lower temperature is required to condense this vapor again into water. To effect this, it must be reduced to a temperature but little above one third of that which has been necessary to convert it into steam; and by reducing the temperature to one-half of the last, it becomes solid. Somewhat similar may it not be with the miasm of yellow fever? It seems to require a temperature of 120° in the sun, or 88° or 90° in the shade, to generate it; although it is destroyed by a temperature as low as 50°. We suppose this miasm innocuous, when uncombined, be- cause we find during the hottest Aveather in cities, when the thermometer at mid-day ranges between 90° and 95° in the shade, there will be no yellow fever, while the air is sufficient- ly agitated with winds to carry off the air which has been freely respired, and is freely charged Avith exhalations from living bodies: for, although the miasm may be generating rapidly at such times, there is no tendency towards yellow fever, until the air becomes stagnant, and often respired, and charged with animal exhalations: when it seems to acquire new properties and new virulence. We know that but a a short time before an epidemic begins to prevail, the most 41 perfect health often prevails among those who become the first victims; although, at other times, cases of common bilious remittents are the harbingers of the epidemic. The latter, we believe, occurs only after much hot, damp weather, and the former after hot and dry weather. We suppose that this miasm is not morbific per se; that it separates itself from pure, free air, and settles to the lowest places; but that it combines actively with impure air, espe- cially such as has been frequently respired; and thus it be- comes a more active cause of disease. When thus combined, we call it malaria or infectious air; and in this state it is a predisposing cause of disease, as well as a suitable nidus for infection. In this infectious air, infection will spread, and yellow fever may be disseminated among the people, by exci- ting causes of a mild kind, or Avithout any. When thus com- bined with contaminated air, it becomes more volatile than before, and diffuses itself more generally in the atmosphere, although it is still heavier than common air, and remains about those places which collect and retain the miasm. II. Infectious Air or Malaria. This combination, when not concentrated, or Avhen moderately diluted with free air, conveys a very slight predisposition to yellow fever: but when concentrated by close, sultry weather, in a dense popu- lation, the predisposition will be so strong that sporadic cases, under highly exciting causes, will occur; especially among strangers, and those Avho are unacclimated. Those who are acclimated escape. If many sporadic eases occur, we may infer the existence of malaria or infectious ai?, and without a change in the Aveather, such as a reduction of temperature, winds, or a rain-storm, we may expect yellow fever to become epidemic. Each case appears to hasten on the epidemic, as if it were by imparting some deleterious property to the impure air at different points, and thus forming finally a fermentative coalescence. If several of these sporadic cases occur in the same vicinity, as it will do if there be many unacclimated 42 foreigners together, the disease will begin to spread from that point. Others who are unacclimated, will be attacked without any highly exciting cause, and finally without any exciting cause except the infectious air about them, which has gradu- ally become infected. When the air becomes highly infected, it appears to be more volatile and in some manner diffuses itself more readily than when in the form of miasm alone, or even of malaria, and it doubtless does possess the power of extending or reproducing itself. The impure air, which unites with miasm, and forms the infectious air, which is the proper basis for receiving and ex- tending the infection, is dependent, we think, chiefly upon the effects produced upon common air at a high temperature, by respiration and animal exhalations, especially from human bodies. This prepares it for the union with miasm. Thus from miasm the first degree of contamination is effected by exhalations from healthy bodies in a high temperature: the second by the accumulated exhalations from bodies laboring under high grades of yellow fever; or, by a much greater concentration of the morbific properties, which appears to take place after, but not before the sporadic cases occur. Our reasons for believing that respiration and cutaneous exhalations effect the morbid change in the air, to form mala- ria, are principally as follows : 1. That sultry weather is always necessary to produce malaria, and to cause yellow fever to spread when infected air has been introduced. I have in no case found yellow fever to become epidemic at any place shortly after it had been tho- roughly swept o-.it by a storm, unless in cases where infected air had been previously generated and retained in the houses. Stagnant air, when exhausted by men and animals, is as de- structive to health and life in them, as stagnant Avater is to fish, when overstocked. Running water always affords a change for fish; and in the large masses of water, they change their places in it. So with air, where from the con- 43 fined situation of a city or district, or from the nature of the buildings and enclosures, or from a general and protracted stagnation of the atmosphere, the air is not sufficiently re- newed, it becomes more or less morbific, by being breathed repeatedly and charged with animal exhalations. 2. When there are sufficient Avinds to sweep out the ave- nues and streets of cities frequently during summer, there is no yellow fever generated as an epidemic, although the actu- al heat, as indicated by the thermometer, may be at least three or four degrees higher, than it is in sultry Aveather, when yellow fever begins. This is confirmed by the history of every epidemic yellow fever Avhich Ave have been able to ex- amine, either in the United States or the West Indies. 3. We know that yellow fever, during our epidemics, pre- vails especially along the margins of the large and deep ra- vines or bayoux, which originate around the city, and spreads mostly in the space embraced in the declivities towards these ravines. The miasm settles in them at all times; and the air contaminated by exhalations and respirations of the contigu- ous population, in sultry, calm Aveather, settles in these decli- vities, and the infectious air becomes more concentrated near the margins of the ravines, and especially in their channels. Gentle breezes, after a long, sultry, calm spell, will sweep over the tops of the houses and points of the hills, but will not SAveep out these bayoux; at most they will agitate and waft it upon those who Avere before out of its reach. In proportion to the distance and the range of elevation above the declivity to the margin of the ravine, so is the immunity of persons. 4. There are other bayoux and ravines, equal to those about Natchez, in the country, but, although they may and do generate miasm as fast as those near, and in Natchez, they do not produce yellow fever; because they have not the popu- lation to contaminate the air, and cause it to combine with the miasm, so as to produce yellow fever malaria. On those 4 1 bayoux or deep ravines in the country, we find only common grades of bilious fever; which is produced by the union of marsh exhalations ivith miasm. 5. The same principles are illustrated by the facts con- nected with epidemic yellow feA-ers in cities differently situ- ated from Natchez; Avhere, instead of bayoux, there are other low surfaces to accumulate the malaria. 6. The same principle is fully sustained in the production of yellow fever on boar J large ships at sea, crowded with human beings, as line of battle ships: these become infected at sea, only when there is a continuation of hot, calm, sultry weather. At other times, only bilious fever Avill occur in them. This malaria, in common seasons, may generate so slowly, or be so slightly concentrated, as to produce no active disease. While in this state, like other poisons, the whole population of a city may be respiring it in such small quan- tities, that they not only feel no inconvenience, but they actual- ly, by habitual exposure to it in its diluted state, acquire an immunity to its effects, even when it becomes more concen- trated. The same immunity to its action is obtained by the development of the disease, provided it be so mild as not to destroy life. This effect is produced by blunting the sensibil- ity to its action, similar to that produced by a continued use of ardent spirits. Those who have undergone this acclima- ting, will remain unharmed during an epidemic, while stran- gers and non-residents will be cut off rapidly by the disease. When the malaria of common seasons becomes concentrated by a continuation of hot, sultry Aveather, or by numerous sporadic cases of strangers, or by infected air introduced, the epidemic follows. Sometimes, doubtless, an epidemic might be avoided, were it not for imprudent exposure to com- mon exciting causes, Avhich, in such a time, oive additional power to the malaria, by preparing the system to its action : or by diminishing the poAvers of the system to resist its ope- ration. 45 We have said the air Avas exhausted by respiration in sultry weather, in addition to the animal exhalations with which it is charged. Doubtless respiration is one of the most potent sources of contamination to the air, when, confined. Wheth- er this contamination proceeds from any new principle or property imparted to the air from the lungs, as carbonic acid gas, ammoniacal gas, or nitrogen; or by depriving it of any property known to chemistry, we presume not to decide. But we believe it is exhausted, to a certain extent, of the vitalizing principle, the "pabulum vita," and at the same time contami- nated Avith animal effluvia. Hence the necessity of winds and storms to carry off these matters and replace fresh air. Ail- exhausted by respiration and charged with animal effluvia without miasm, will produce fever; and the same at a low temperature will produce common typhus, jail, and ship fever. The same with miasm in a hot climate will produce yellow fever. The most rapid effects from exhausted air on record, are those of the hundred and forty-six Englishmen, confined in the "black-hole" at Calcutta, of whom all but twenty-three died in less than eighteen hours, with all the symptoms of a most malignant and ardent fever, produced solely from ex- hausted air charged with human effluvia. The general atmosphere sometimes in hot, sultry weather, seems to possess this vivifying property in a less degree than common. This state of the atmosphere is indicated by a sense of oppression under which all animals appear to labor, as evinced by the relaxation of the skin, and profuse perspira- tion ; and the rapid respiration or panting, especially after even moderate exercise. When this sensible condition of the air exists longer than a very few days, with a temperature during the day ranging betvveen 88° and 95° in the shade, and from 80° to 85° at night, with a calm or serene atmosphere, whether cloudy, foggy, smoky, or hazy, we may be sure the miasm is accu- mulating, and especially in cities, the air is rapidly becoming 46 contaminated, and will lead on to an epidemic yellow fever, without a change. This crisis may be expedited by the intro- duction of infected air, or of patients laboring under yellow fever. Or if many persons in the city go on board a boat or vessel which is infected, and subsequently are attacked with yellow fever in the city, during the continuance of such a state of the weather as Ave have alluded to above, we may ex- pect other cases to spring up in their vicinity; and, Avithout a timely change of Aveather, the local air Avill become so infect- ed as to spread the disease to others. This is what is termed by some "an epidemic constitution of the air"-—for all admit that, at certain times, infection of yellow fever, as well as of other diseases, will spread rapidly—and, at other times, it will not spread at all. Thus we believe that the union of miasm with air exhausted by respiration, and charged with human and animal exhala- tions, in a hot temperature, produces the malaria of yellow fever; and that this may be more or less concentrated, and of course more or less morbific : that when to this is superadded a sufficient portion of the morbid exhalations of yellow fever patients, it produces the third degree of the morbific agent of yellow fever; viz: III. Infection. This appears to possess properties dif- fering from those of the malaria in several particulars. It seems to possess, in addition to its morbific properties, the pro- perty or quality of assimilating to its own nature any impure or confined air into which a suitable portion of the infection is introduced. Thus the whole air in a room or ship's hold, when properly prepared for the prolific reception of the infec- tion, Avill, in a short time, be converted into an infected air equally as strong and active as the small portion first intro- duced. From its analogy to common ferment, I have called it a gaseous ferment,meamng that change which my friend Dr. Cartwright expresses by the phrase "assimilating process." * ' Med. Record, vol. ix-x. 47 There appears a striking analogy between the common process of carbonic acid gas fermentation and this gaseous ferment, viz: in the former it is requisite to have a suitable vegetable basis, of a certain consistence, at a certain temper- ature, for a longer or shorter time, to produce the effect. This effect will be greatly expedited by introducing into the basis so prepared a portion of ferment or leaven; although the same effect Avould be produced without it after a longer time, When the fermentative process is complete a portion of the fermentated basis introduced into another basis in a suitable temperature, will excite the same action ; and so on ad infi- nitum. This ferment, although it require a temperature from 70° to 80° for its production, is not destroyed when once produced, by any moderate change of temperature. If a portion of this leaven be introduced into an unsuitable basis, at an improper temperature, it will be neutralized and lost. So il appears to us is the gaseous ferment of yellow fe- ver. It requires a basis of impure air, exhausted by respi- ration, and charged with human effluvia, at a regular tem- perature for a certain time, to produce it in the first place: but when a portion of the infection already formed in an- other place is introduced, the assimilating process takes place much sooner, and probably without the same degree of heat or contamination that would be necessary to gener- ate it ab initio. This "leaven" of infection when introduc- ed into several points of a malarious district, will much more certainly institute the assimilating process, than if it Avere introduced at one or two points only, and in small quantities. If introduced into pure air it becomes neutralized and lost. Upon this principle we may explain why it is so necessa- ry to desert an infected district, to check the spread of the disease; for thereby, we not only prevent the formation of the malaria, or basis, but likewise remove the sources of in- fection or " leaven." The air becomes more pure by re- 48 moving those who contaminate it, and new cases of fever in the contaminated air, or malaria, are prevented. If this pre- caution is taken soon after the first few cases, before the gen- eral air of a district becomes infected, the spread of the dis- ease may be arrested : for in ten or twelve days where res- piration has been suspended or intermitted, the air loses its peculiar adaptation for supporting the assimilating process. The fermentative process ceases for want of a suitable basis; and the miasm settles down near the ground in its simple, harmless state, or is wafted off by winds. But if the popu- lation remain contaminating the air at such time, until it be- comes infected, rains may wash portions of it into bayoux, and winds may sweep all infected air from the streets, but there will remain sufficient of the infected air in the houses and enclosures to institute the fermentative process again from a hundred sources. The properties of infection, or infected air, so far as can be ascertained are as follows, viz : 1. It is a gaseous poison which is diffused in the air at certain times, or may be contained in confined air of houses, ships, and even in bales of goods. It is more volatile than simple miasm or infectious air ; and diffuses itself further and insinuates itself more intimately and extensively in the at- mosphere of a city; and when concentrated produces yellow fever in its most malignant forms, in from three to five days from the exposure, without any exciting cause. To bring the system under its influence, it is necessary only to breathe it for a few minutes, or an hour or two, according to the degree of concentration. It so acts through the nervous sys- tem, upon the whole of the vital functions, as to produce a malignant fever, which mostly terminates in death, after from one to five days. 2. When a suitable quantity of it is introduced into the proper kind of air, at a suitable temperature, without the free admission of pure air, it acts as a ferment, and re-produces 49 a larger amount of infection, equally efficient with that first introduced. In this way it will assimilate the contiguous air and diffuse itself as extensively as the malaria. A large amount of it introduced, will be diffused in an atmosphere less contaminated than actual malaria, and assimilate, or ren- der infected a much greater amount of air. Although a small quantity diffused in a pure atmosphere so as to become much diluted, loses its fermentative properties, as well as its morbific. These properties we find indicated by the infection having become as virulent as ever in a feAV days after a severe gale or storm must necessarily have swept off all the loose infec- tion from the open air. The infected air in each house is a source for re-infecting the general air of the city or infected district. 3. When air is moderately infected, so as not to produce active disease, by being closely confined, at a temperature be- tween 85° and 95° it becomes more virulent in a few days. This is confirmed during every epidemic, in this known fact, viz: that a house may be deserted early in the epi- demic, when the infection in the general air is weak so as not to have excited disease in any of its occupants : yet when they have fled, and the house has been closed for a month or longer, if any of those same members, or others from the country return to that house, occupy it, and sleep in it with- out proper ventilation and exposure to cold or frost, they will contract yellow fever of a high grade and probably die. The air contained in beds left in such houses has been more close- ly confined than the free air of the room, and at a more regu- lar temperature, and of course is more virulent. It is upon this principle as well as that of section 2nd, that cleanliness and ventilation are so essentially necessary about patients laboring under yellow fever, lest it may accumulate in a stagnant air and become a new source of infection. For, as Dr. Paloni, of Naples, observes, of the yellow fever of e 50 Leghorn, which swept off seven hundred souls in that city in the autumn of 1804: " The infection of this fever is of such a constitution, that pure and renewed air decomposes its fames at a small distance from the sick : on the other hand, air that stagnates and is replete with animal exhalations, easily be- comes a vehicle for it. Hence it happens that as soon as the disorder broke out, we saw it rage most fiercely in the most filthy and least ventilated parts of the city. Pure, fresh, re-> newed air destroys its infection." Med. Repository, vol. 8, p. 426—7, &c. In this case the Doctor's views are correct, and unusually discriminating; and we Avould suggest that the manner in which the infection was decomposed, was for Avant of the malaria or infectious air, which alone will afford it a suita- ble nidus for the fermentative process. Hence the wisdom of free ventilation with the sick, as inculcated by all who have been conversant with this fever; and the reason why it is not known to spread, in a country air; and why in a city the malignity of the cases and the succession of cases increase with each case attacked in sultry hot weather, un- less the people fly. 4. When infected air is confined in rooms, &c. it is not destroyed by any degree of cold short of 40° Fahrenheit; and to destroy it entirely nothing short of 32° will suffice. Hence it often occurs that the infected air of houses pro- duces yellow fever in those entering them even after frost and ice; for a mild frost will take place at 40° —and al- though the temperature in the open air may be reduced to 32°, yet the temperature in closed rooms is most probably not beloAv 40° or 45°. To destroy infection requires the tem- perature reduced 15° or 20° lower than is requisite to neu- tralize simple miasm. 5. This infected air is supposed to be more volatile than miasm to be volatilized by the sun and partially condensed in the cool dews of night: hence when there is much in- 51 fection in the air it may be more dangerous to be out at night than in meridian day. Thus the night-watches gen- erally suffer severely. 6. The infection insinuates itself into blankets, feather- beds, woollens, and other porous articles, and in this way may be carried from one place to another. But the in- fected air thus transported avi'11 produce the disease only in those who breathe it before it is diluted Avith common air : it might spread when taken into a close room and kept in stagnant v\rarm air. 7. Like miasm it is heavier than common air; and set- tles in low damp places, and bayoux; so that when there is but a moderate quantity in the general air it abounds in such places, in proportion to their depth and Avidth, and the de- clivity to their margins, until its surface comes upon a level with that diffused abroad. Thus when abundant it may be ten feet deep near the margin of a bayou, and not more than three feet deep one hundred yards distant. 8. It is supposed to adhere in some manner to wood and such like bodies, especially, more than to brick, stone, plas- ter, &c. Hence we find wooden houses more frequently be- come infected and remain so even after one or two frosts; be- cause it is more tenacious of wood, which maintains a higher specific temperature than stone or brick walls. Hence the great difficulty of disinfecting ships until cold weather com- pletely neutralizes the properties of the infection. We will here make a few remarks again upon the gener- ation of miasm on board ships in tropical climates. The confined air in the holds of ships is more likely to be ex- hausted by respiration, and charged with human effluvia than even a city ; especially where there are many souls on board, who are often confined below on account of storms and winds. In them thorough ventilation is extremely difficult, and the temperature is almost constantly up to the miasm point The infectious air is thus rapidly formed in mary 52 cases, and in this state, a vessel arriving at a port where yel- low fever prevails, will be ready to receive the leaven from the infected air of the city, either by the crew visiting the in- fected districts on shore or by the introduction of the infec- tion in the form of fames in goods. The United States fri- gate General Greene, before referred to, is a good illustra- tion. The temperature at sea in tropical latitudes is seldom be- low 80° of Fahrenheit, and often from 90° to 100° according to the degree of reflection and concentration of the 6un's rays. By a register kept by Dr. Thos. Rodman,* embracing thir- ty observations between the first of November and the fifth of December, at 12 o'clock M. each day, betvveen latitude 22° north, and 22° south, it was ascertained that the lowest temperature of the air was 79° and the highest in the shade 86*. The lowest temperature of the sea below the surface was 78°, and the highest 84°. The mean temperature of the air during that time, at 12 M. was 83°, and of the water 81° Thus the temperature within vessels Avhile in tropics cannot be low enough to destroy or neutralize miasm, much less infection: the former requiring a temperature of 50° and the latter of 32° Fahrenheit. Thus, however slowly it may be generated, it continues to accumulate until the ship enters a northern climate. This register was kept during a cool healthy season, when no disease was generated on board, by hot, calm and sultry weather: of course a much higher temperature in these respects is often experienced on board ships in the tropics; and the miasm and infectious air is of- ten generated Avhere no animal or vegetable putrefaction exists. The generation of miasm in cities, as has been before re- marked, has taken place under every variety of circumstance as regards animal or vegetable decomposition; as well as where neither existed. Under all the circumstances Avhich ' Vide Ooxe'9 Mpdic»l Museum, vol. I, p. 83—4. 53 have been presented to our view, we cannot conceive it pos- sible for such a general morbific agent, to be eliminated from such a diversity of sources and each so limited in their nature and extent as those to which it has been ascribed. As well might we expect to see a territory inundated by a rivulet as to believe the atmosphere of a city should be infected with a pestilential miasm from a few bushels of rotten coffee, a few barrels of oysters, a dead horse, or a filthy back yard. The cause is inadequate to the effect. If so small a cause could produce such general effects it Avould be an anomaly in na- ture. Besides, it would be strange beyond comprehension if a peculiar miasm could be generated from a hundred different sources, and under as many different circumstances: for the causes and circumstances necessary for the production of yel- low fever, as generally maintained by the advocates of vege- table or animal putrefaction, are almost innumerable. In medical investigations as well as in some others, we are too apt to direct our attention exclusively to a few apparently prominent circumstances, which strike some of our senses, and make all our deductions from them; as if all the opera- tions of nature were known to us; or as if nothing Avas car- ried on in the natural world, except the few comparatively gross operations which are cognizable to our few and imper- fect senses. Hence it happens, that in attempting to trace the secret cause of yellow fever miasm, as it is called, Ave have been led so often to those things which are offensive to our senses; notwithstanding the same exist equally when no yellow fever prevails; and notwithstanding the poison of yel- low fever cannot be detected by any of our senses. We doubt not, the precursor most essential to yellow fever epidemics, at Natchez, as well as elsewhere, will be found to be hot, calm, sultry weather, for ten or fifteen days in succes- sion, immediately before it breaks forth. If no infected air Hp introduced, the disease will not manifest itself in so short 54 a period as otherwise, nor in air as slightly contaminated as otherwise. We conceive the vicissitudes of weather, whatev- er they may have been a month or six weeks previously, have no immediate effect upon its production. In all probability, the effects necessary for an epidemic are elaborated principal- ly within twenty days or less, immediately previous to the ap- pearance of the epidemic. Although the miasm is elabora- ting continually during hot weather, it never accumulates in such quantities as to produce disease, until after several hot, calm, sultry days, during which time also, the air, being stag- nant, becomes exhausted and charged with exhalations. If, after a week or ten days of clear, hot, sultry weather, calm, cloudy, or foggy weather succeed, at an extreme temperature during the day, of 85° to 95°, the miasm still continues to ac- cumulates, though more slowly, until strong Avinds or cold nights succeed. Upon this principle, do we account for yel- low fever having prevailed in calm, cloudy, or wet weather, although it did not appear during the previous hot and dry weather. The most common appearances obseived in the weather, immediately preceding yellow fever, are as follows; viz : the temperature in the shads, from 88a to 95° at noon, with Avarm nights, for ten or fifteen days, at least, in succession. During this time, whether the weather be clear or cloudy, or attended with moderate rains, the air is not agitated by any strong winls, sueh as sweep out every part of a city; the air feels oppressive, and respiration is oppressive. During such times, especially in August and September, every precaution should be observed, until a change of weather ensues; a por- tion of the population should disperse; strangers and unaccli- mated persons should leave the city, all unusual exposure should be avoided, all fatigue, debauch, or intemperance, or irregular hours, should be strictly avoided, at least until after a favorable change of weather. Every precaution necessary to keep up a proper equilibrium of the healthy functions .')5 should \vi punctiliously observed by those who value their lives above a few dollars, or above temporary sensual gratifi- cations. This remark is especially applicable to those who are properly unacclimated. I shall now proceed to give a sketch of the history of the different yellow feArer epidemics of Natchez, with a few re- marks relative to each. I. The Epidemic of 1817 is considered as the first in the history of Natchez; although I have been very credibly in- forme-jd, that individual cases Avere often seen previously, some of which, I have been informed, appeared to have ori- ginated in the city; and others derived their infection from New Orleans, or from infected boats. Dr. Tooley informs me that occasional cases occurred about the city in 1817, as early as July and August; it did not become epidemic, how- ever, until the 28th of September. Dr. Perlee* says the state of the weather had been such as predisposed very strong- ly to violent disease, even in the early part of September, and "required only a small concentration of power to produce a sweeping epidemic^" " At this time," says he, " when the population was highly susceptible, the Washington steam- boat reached us from New Orleans, with persons on board ill of yellow fever; some of whom were landed; and several young men from town Avent on board, who were all taken sick soon after and died. The disease spread rapidly, and with most destructive malignity. For some time it had its sway over the whole city. On the 28th of September, the physicians publicly announced the existence of yellow fever ; and a large portion of the population retired to the country." On the 1st of October, the President of the Selectmen, Ed- ward Turner, issued a circular, advising the citizens to seek refuge in the country, and regretting, at the same time, that the disease had been in the city several days before it was an- nounced. The disease continued to prevail among those Avho * Chapman's Mec! Jour, v 3, p. 6, 56 remained until about the 9th of November; and several cases occurred among those who returned as late as the 15th of that month. The whole number of deaths in the city during this epi- demic, was one hundred and thirty-four, besides some who contracted the disease in the city and died in the country. Dr. Perlee states that the number Avas estimated about three hun- dred : but that is doubtless an exaggerated estimate. The population of the city at that time Avas comparatively small. The epidemic commenced late, and terminated rather early. From a meteorological table given by Dr. Perlee, it ap- pears that the mean temperature of July Avas 80°, of August 77°, of September 73°. The quantity of rain up to the first of September, was rather more than usual; being in July 3-95 inches; in August 4-41 inches: in September 1-92 inches. I have not been able to ascertain what was the daily extreme temperature of September; although Dr. Perlee informs us it Avas a hot, sultry, and humid month. The " predisposing causes," to which Dr. Perlee ascribed this epidemic, are exhalations from city filth; from grounds newly made in leveling the streets; from stagnant water in the streets and cellars; from the old grave-yard near the cen- tre of the city. These various exhalations, he supposed, produced a high state of "general predisposition," and with " other causes of insalubrity" prepared the inhabitants for an epidemic, so soon as any exciting cause should occur, or so soon as any concentration of power should take place in the predisposing cause. This he leaves us to infer, was effected by the introduction of infected air and yellow fever patients from the steamboat Washington :—for besides several yellow fever patients landed from her,—the air in her cabin was so highly infected that of " several young men from the city, who went on board, all took the disease, and soon after died." Imme- diately after these cases the disease manifested itself in vari- ous parts of the city. 57 The yelloAv fever prevailed severely in iSew Orleans, in 1817, for several weeks previous to its appearance in Natchez. II. The Epidemic of 1819. The first alarm of yellow fever was given on the 4th of September, at which time seve- ral cases had occurred, and a portion of the citizens immedi- ately fled to the country. Cases became more frequent, and more malignant in their type until the 14th of September, when it was considered epidemic. It continued to prevail with great mortality until the first of December. At this time about 200 persons of all kinds had fallen victims to its ravages, and the total number of cases was over 400. Some, as in 1817, died after they had fled to the country; and oth- ers after they had returned to their homes, and imprudently slept in their houses and beds before they were perfectly dis- infected by cold weather. The total deaths as given in the sexton's reports, during the epidemic, in the city, were about one hundred and eighty. On the 3d of October, when only about seventy-eight deaths had taken place, a census taken showed the entire population, including blacks in both the upper and lower parts of the city, to be only five hundred and sixty-eight souls. Subsequently about one hundred of this number died; of whom about fifty died in the month of Novem- ber. Several cases and deaths by yellow fever were reported as late as the 3d, 4th and 5th of December. A report made by the board of health during the epidemic States, that the inhabitants of the country, and in the immediate vicinity of the city, were as healthy as usual at that season. The meteorological table given by Dr. Perlee shows that July and August were very wet, and September very dry. The rain-guage gave in July 12-27 inches; in August 8-05 inches; and in September 0-95 inches. The mean heat of July was 79°, of August 79°, and of September 75a. Thus July and August exhibited a lower mean temperature, by 3- than the same months in 1818, which Avas a healthy year. The mean heat of September, 1819, was the same nearly as in 1818. Hence we see that the yellow fever in 1819 pre- vailed under the same temperature, or less, and with more than double the quantity of rain Avhich preceded the epidemic of 1817.—The month of November, in 1819, exhibited a higher mean temperature than the same time in the preceding ten years ; being 65°; Fahrenheit, or three-fourths of a degree higher than than the mean temperature of November, 1837. Dr, Perlee ascribes this epidemic to the same general causes Avhich, in his opinion, produced that of 1817. He supposes the excessive rains in July and August caused a stronger "predisposition," as during the healthy summer of 1818 it Avas comparatively dry and healthy* As to the par- ticular portion of the city in which it prevailed in 1817 and 1819, Ave are not informed; but doubtless it occupied that part of the city in which it has prevailed in each subsequent epidemic. The yellow fever had preArailed to a most alarming extent in New Orleans, for about two weeks before it appeared in Natchez. There had been scattering cases about the ship- ping, boats and wharves, as early as June; but it did not become epidemic until about the middle of August. It raged severely among the shipping, and spread to the adja- cent streets, as also among the boats which had descended the river. Not a ship escaped one or more deaths, and some lost their whole crews ; many steamers became infected, and lost many of their passengers and hands. It did not entirely cease there until near the last of January, 1820.f During the years 1820, 1821, and 1822, yellow fever as an epidemic, was unknoAvn in Natchez. Yet, in each of these years, especially in 1822, there were several sporadic cases, and some whose infection was derived from New Or- leans, by handling, opening, or sleeping on blankets, &c, "In 18IS, the rain of July, August and September, together, being only 10^ Inches, or less than that of July, 1R59 t In Med. Rep., New Series, vol. »lp », 6, 7, 8, 9, 10, 1»- -?0. 55 isom the infected district of that city. The state of the Aveath- er during these summers I have not been able to ascertain The Epidemic of 1823.—This was probably the most extensive and terrific epidemic yellow fever which has visited this or any other city of its population. It commenced in scattering cases in the south-western part of the city on both sides of a large gully or ravine, which heads on the north- west side of the town, and also in the vicinity of other bay- oux of the same kind, which extend up to the block of the city at several points on the south side. During the preva- lence of the epidemic, those sites, near those bayoux and in the declivity towards them, from the adjacent hills, were the chief seats of the disease; although it finally extend- ed over a large portion of the city. It was about two weeks after the epidemic appeared, " on the hill," before it ex- tended to that portion " under the hill," at the landing. [Med. Record, -above cited. We believe that the cause, or essential agent of yellow fever miasm, is beyond our control, and our only safety is to mitigate its effects, observe its approach, and flee from it. We fear the public attention and our city au- thorities have been too much drawn to matters which have 'North American Journal of Med, and Phys Sciences, v. 1. p, 65 no agency in the production of yellow fevers; or at most on- ly a subordinate and contingent agency. As a necessary consequence, they have entertained a fallacious hope that se- curity would result from the removal in time of such causes as were supposed to generate the pestilential miasm. They have thus been lured into a false security, which has often resulted in their disappointment. We have no preconceived theory to sustain; our views are such as are the result of an unprejudiced inquiry into the different circumstances of the many epidemics which have occurred in various cities of the United States and of other countries. If the alleged causes are not the true source of the disease, we shall at least pre- vent a false security being placed in such means as really af- ford no safety; while we urge the necessity of speedy flight upon the first appearance of the pestilence. If it can thus be avoided, that fact alone will in some degree disarm it of its terrors. Wevv/w(.t«a -».«* jvH^w re?cj, aou.. ^,u-^. icuj iL. pendent for its production upon animal or vegetable puirr. faction, or upon the union of both ; and that when these mat- ters have been observed to precede an epidemic, it was only a contingent, and not essential circumstance. My views on this subject are ably expressed by Dr. Cartwright, in his es- says on the " Malignant fevers of Natchez." Aftffealluding to "some of the circumstances which are necessary for the production of yellow fever," he observes, "although yellow fever may not occur any two years in succession, yet the ef- fluvia to which it is erroneously attributed, may exist every year in an equal degree. Effluvia-, as mere effluvia, are innoxious, and should not be confounded with miasm, which ii the real cause of yellow fever. We all know, that when yellow fever has become epidemic in a city, it continues to prevail until it is checked by frost, in defiance of all precau- tions which can be taken to arrest its progress. All the ma. terials which are in a state of putrefaction, may be removed ; M\ the air, before moist, may become dry, the evaporating prO> cess may be suspended; and the mercury may fall 30° or 40° below the point at which it stood Avhen the disease first appeared; yet it will continue to prevail after every one of its supposed causes have been removed. * * * If efflu- via produce it; if evaporation or moisture produce it; or if all these combined produce it; what should give rise to the disease when each and every one of these supposed causes are removed? " [ Med. Recorder, vol. x., p. 229, 230. We answer, nothing but a subtle, invisible, and imperceptible miasm, Avhich is produced independently of all such circum- stances. Some have supposed that a peculiar miasm is gen- erated during the putrefactive process, but not necessarily foetid. In our opinion, neither foetor nor putrefaction are at all concerned in its production: for we have shown that not even the putrefiable materials are necessary. The advocates of animal putrefaction admit that the epidemjc of 1825, "on the hiU " jiku>-t'"'~'Jv*v'"1 "f1*1^1*1- pcrtiiu ««.w«m«i nmucis or any kind; and no one pretends to ascribe the epidemics of 1829 and 1837 to such causes. These two epidemics are ascribed to city filth, to filthy and wet sewers and back yards; the same causes which Avere said to have produced the fever of 1825, on the hill; causes which were not called into requi- sition at all in 1823, although the most extensive and fatal epidemic Avhich has yet visited the city. According to the theories heretofore advanced, no two epidemics have ever been produced by the same cause: and upon the same prin- ciple, every succeeding epidemic, if we should be so unfortu- nate as to have others, will depend upon a new cause. The inference is, clearly, that the causes of yellow fever are innu- merable. We leave our readers to determine whether the premises are tenable. But Ave have testimony incontrovertible that city filth is not necessary to its production; nor is it at any time an aux- iliary cause; as the disease prevails generally when there is 63 least of this existing; and often where it is most abundant, there is no yellow fever produced. Dr. Rush* even declares that the city filth in the sewers, alleys, and streets of Phila- delphia, appeared to absorb the pestilential miasm, and thus to produce a partial protection against it. He declares that during the memorable epidemic of 1793, in that city, scaven- gers seemed especially exempt from its effects; as only one out of forty Avas attacked with yellow fever. This is con- firmed by the experience of Dr. Tilton.f He states that it is injurious to remove city filth during an epidemic, as the filth seems to absorb the miasm, while the exposed pavements from which it is removed augment the reflection of the so- lar rays, and increase the miasm. On the same principle, it is belieAred by some, that fresh earth, strewed over the streets, might be beneficial to a certain extent. A mass of authority might be adduced, to show that common city filth or offal is not a cause or source of pestilential diseases. Natchez is not more filthy than hundreds of other cilies where no yel- low fever exists. If city filth were a cause, we know not how it could ever occur in the cleanly and scattered village of Washington. We cannot believe that the removal and exposure of fresh earth in digging down the streets and filling up low grounds, are essential or even auxiliary to the generation of yellow fever miasm. More or less of this has been done in Nat- chez every year; yet, for the last six years previous to 1837, there has been no epidemic yelloAv fever in the city. And, again, we know that yellow fever prevails much more fre- quently, and more extensively, in New Orleans and other cities, where no such digging is done, or is even practicable. Extensive excavations and embankments have been carried on in different parts of this State, during the last year; yet in no case has yellow fever been generated from it. One • Med. Inquiries, vol. n.. p. 1W, eaition of 1815. i Med. Repos. v. ill.,p. 1t of September, when some cases in Natchez began to assume malignant symptoms. Several deaths by malignant fever occurred in the city, as Avell as at the landing, between the first and sixth of September. On the 8th of September, considerable alarm prevailed in the city, and the Board of Health, after receiving the reports of the medical faculty, advised the citizens to disperse. The reports of the physicians shoAved that there Avere then about twenty cases of malignant fever under treatment in the upper city and at the landing. The majority of the citizens imme- diately retired to the country and to Washington. The dis- ease continued to prevail moderately among those who re- mained until about the last of October; a few cases occurred in those who returned into closed houses, as late as the 8th and 10th of November. During this epidemic, the whole number of deaths in the city, by yellow fever, did not exceed eighty-five or ninety. The whole number of cases was prob- ably near three hundred ; although many of them were mild, and assumed the character of high grades of bilious fever, attended with profuse discharge of yellow bile. The summer was rather wet, until the latter part of Au- gust: in September there Avas less rain; the heat was often oppressive, and the air sultry. No unusual form of disease prevailed in the country: but the health of the country gene- rally was as good as common at those seasons. This year the yellow fever did not prevail much in New Orleans, until the 24th of August; and it first appeared in Mobile about the 26th of September. So far as I have been able to learn, all seem at a loss to as- cribe this epidemic to any adequate cause. Some, however, seem inclined to ascribe it to the old, exploded one; viz: ex- halations from earth recently exposed by digging down and leveling the uneven surface of the city, Doubtless the same general causes which produced the other epidemics of Nat- chez in other years, produced this, independently of any local accumulations of filth or putrtfiable matteis: and of the re' moval of earth in leveling the streets of the city. From 1829 to 1837, there was no epidemic yelloAv fever in Natchez; although a few sporadic cases were seen occasion- ally under peculiar exciting causes; and frequent cases Avere landed from steamboats direct from New Orleans, and carried to the hospital. So long had been the intermission of epidemic malignant fever in the city, that the inhabitants began to entertain the hope, if not the belief, that the strict attention of the police to the cleanliness of the city, would finally redeem it from other visitations of the pestilence: especially was it believed, that lime, which had been freely used, was an important prophy- lactic. VI. The Epidemic of 1837, began by a few sporadic cases about the 8th and 9th of September, and became epi- demic about the 15th. Yet the cases Avere not numerous or very malignant until about the middle of October. In the first ten or fifteen days of its prevalence, many cases were so- mild or so modified as to create doubts in minds of many whether the disease were really malignant yellow fever. Du- ring this time, if efficient means had been taken to cause the population to disperse, and desert the city, we doubt not the pestilence might have been stayed: but it was not until near the 25th of September, that the Board of Health or the city authorities, eould determine, from the opinions of the medicals' faculty, as to the actual danger Avhich the citizens would en- counter by remaining in the city. For want of timely no- tice of the danger, the dispersion was gradual and slow, even until the middle of October. The disease continued to pre- vail, with occasional abatements, until the 25th of November ; although the prevalence of the disease was much checked by the cold winds and frosts which occurred early in November. During the prevalence of the disease, from the 8th of Sep- tember to the 25th of November, when the last death occur- 7G red. th.j whole number of deaths, of all diseases, was about two hundred and eighty, within the city and at the hospital. Several of those at the hospital, were patients landed from steamboats direct from New Orleans. Besides those, there were ten or fifteen who died at different places in the coun- try, whither they had retired, after having imbibed the seed a of the disease in Natchez. So that the entire number of deaths from this epidemic, might be near three hundred. In the early period of the epidemic, especially, the number of recoveries were much more numerous than th