UNITED STATES OF AMERICA FOUNDED 1836 WASHINGTON, D. C. GPO 16—67244-1 0(1 NEW THEORY YE1L1LOW IEYE15 FOUNDED ON THE RESULTS OS CHEMICAL EXPERIMENT BY JAMES TINSLEY, M. D. GRADUATE AT THE UNIVERSITY OF PENNSYLVANIA, HONORARY MEMBER OP THE PHILADELPHIA MEDICAL SOCIETY, AND MEMBER OF THE MEDICAL-SOCIETY OF SOUTH-CAROLINA. CHARLESTON, 8. C. PRINTED BY W. P. YOUNG AND SOX. ISlft. 1 PRELIMINARY REMARKS. It is generally admitted, that in all invest:gations into sub jeets, whose conditions are complicated, too much precis on cannot be exercised in prescrib ng certain rules of ratiocination by which we should be governed in our results. The following, therefore, will cla m the particular attention of the reader in the perusal of th;s ess-y. 1. We should never recur to invisi- ble agents or gratuitous principles to explain effects, while such as are obvious, and more intelligible, can be demonstra- ted to be adequate. 2. In explaining the operation of a power to which an effect !s referable, we should never assume prin- ciples that have not been proven to be true 3. Where several powers can be shown to co-operate in the production of an ef- fect, we are bound to include the whole, as constituting the true cause of such effect. 4. If an explanation be shownto be founded upon principles, directly contradicted by observa'ion and experiment, the theory again returns to its* original cha- racter of a gratuitous position. The importance of these rules will be highly evident, on a superficial view, particularly as relating to the doctrines of electricity, contagion, and mias- mata; these being the only ones whose error I have deemed it necessary to expose. Indeed, much of their futility, it will be perceived, consists in an open violation of some one, or all of those maxims of legitimate argumentation. The tendency of auch violation, must place us in the predicament of advancing opinions devoid of proof, direct or presumptive; of taking such a partial view of a subject, as to assign but a part of the real cause; of supposing an effect to be produced by a power, which, from its nature, can act but a negative part; of being led to conclusions that have but a negative connec- tion with the data assumed; or, of establishing inferences which are foreign to, or unwarranted by the premises from which they are drawn. In addition to this, there is another view which may be taken, of the three hypotheses above allu- ded to, equally indicative of a common error. I have enume- rated heat, moisture, putrefaction, vegetation and respiration, as the principal powers concerned in the production of yellow lever; or, at all events, I have demonstrated that they all absolutely co-operate in bringing about a condition of the at >c / IV mosphere, which is confessedly, prejudicial to health. Now, the authors and advocates of electricity and contagion reject the whole of those known powers, and adopt principles shown to be gratuitous; while those who refer the disease to miasma- ta from putrefaction, reject all the rest. But common sense tells us, that to produce disease, it is only necessary to disturb those agents upon which health depends. The principal one, in the present case, is atmospherical oxygen, whose ordinary quantity has been shown to be diminished by all of the cumstances enumerated, except electricity, contagion an>. asmata. Admitting, however, that any one of those circui. stances gives rise to yellow fever, it would evidently follow that there are two ways of effecting it, viz. by a, pari of the real cause, which is efficient; or, by the whole taken in con- junction, which, nevertheless, lies idle—which is absurd. Should my own notions be found erroneous, I shall cheerfully relin- quish them: I trust, however, that what I have endeavored to substantiate, will not be deemed unworthy of farther con- sideration and research. NEW THEORY, &c. CHAPTER I. The opinion advanced in this essay maintains, that the cause of yellow fever consists in such an enlargement of the general atmospheric mass, relatively to the quantity of oxygen which it con- tains in a given bujk, as to preclude the requisite quantity of that vital portion from entering the lungs at each inspiration. The powers which are suppo- sed to give rise to this enlargement, are heat, mois- ture, miasmata, the vegetation of plants, the respi- ration of animals, and every other circumstance in nature, capable of such an action. The grounds and reasonings, by which this opinion is thought to be legitimately substantiated, are to be found in the following pages: Ground 1. It is now generally admitted, that the healthy energies of all vegetables, as well as ani- mals, throughout both kingdoms of animated na- ture, absolutely require a due and uninterrupted supply of oxygen gas for the performance of their functions: This gas essentially constitutes one-fifth of the bulk of the atmosphere in an uncontamina- ted state; and as it relates to animals in particular, it is in this combination that it subserves the purpo- ses of vitality best. I believe, to these positions, as relating to those two classes of living functions, there has never been discovered an exception, ei- ther in the natural history of their subjects, or in the demonstrations of experimental philosophy. Again, during every living process, as it lelates ti to atmospheric influence, under a healthy, vegeta- tive action, both by the germination of seeds, and the vegetation of plants, as well as, by the respira- tion of animals, the oxygenous portion disappears, and a corresponding quantity of carbonic acid is produced in its stead, without in any manner affec- ting the azotic principle of that fluid. When the due supply of pure air is kept up, the beings whose actions depend upon its agency, are uniformly ob- served to be energetic, and to perform all their functions with perfect facility and vigor; and in proportion as the vital ingredient is abstracted, they become sickly, enfeebled, and their energies, in eve- ry respect impaired, or entirely suspended. These are truths, which are so well established, at the pre- sent day, as to render it superfluous to insist longer upon their correctness in this place. Those, who may have any doubts, would do well to consult the latest authorities on chemistry and physiology, and particularly a work by Mr. Ellis on air, together with the authorities to which he refers. Ground 2. On a minute examination into the history of the disease, I feel warranted in drawing a conclusion that, it never occurs, but at those pla- ces where, and during those periods of the year and weather, when every natural cause which is calcu- lated, and necessary to create this enlargement of the atmosphere above-mentioned, is brought in- to operation in its highest intensity. By thus in- variably preceding, or accompanying the disease, I think there can be but little doubt of there being some necessary conneixon between their agency and its existence. Ground 3. When that period of the year rolls round, or that state of the season occurs, which either by its initial, or consequential impression, suspends the operation of those cause?, which alone / can produce a derangement in the proportion which the oxygenous principle ordinarily bears to the whole bulk of the air, the existence of yellow fe- ver, invariably vanishes. Does not this argue, upon the face of tlie fact, that, if those causes are not the direct agents in the production of the disease, there may, at least, be a very close association between them upon some natural principle. By an expo- sition of the manner, in which these causes are presumed to operate, this connexion, I think, will be amply indicated. Ground 4. So far as I am able to deduce causes from their effects, and to trace the connexion which physically obtains between them, I feel constrained, after an impartial investigation of facts, and circum- stances, and upon every principle of fair argumen- tation, to conclude, that, in no country, nor du- ring any season of the year, however aggravated a form it may have assumed, has yellow fever ever manifested a contagious tendency. This is the ge- neral sentiment of the day; I believe it has been, in a great measure, the opinion of a majority of those who have had most experience ii>its practice ; and it is one, which I conceive, would follow as a natural and necessary consequence, if my first po- sition be correct. Ground 5. Persons from an elevated part of the country, from high latitudes, and other situations, where the causes above alluded to, cannot be sup- posed to operate in a high degree, are far more lia- ble to an attack, than natives and long residents of the place where the disease prevails. The rela- vancy of this ground will be obvious upon a deli- beration of the force and influence which habit is known to exert, over the feelings and movements of the animal economy 8 I might here detail many other con si derations, from waich cogent deductions might be drawn in favor of the doctrine contended for; but their bear- ing not being direct, and to render them sufficient- ly clear would require a latitude of discussion and detail, not at all anticipated on the present occasion, I shall mention but one more ground of material importance to my purpose. Ground 6. The total, and generally acknow- ledged inadequacy of every hypothesis hitherto ad- vanced, either to develope the causes of the disease, or to expose the manner in which they have been supposed to exert their energies in its production. The validity of this latter ground can only be test- ed by a concise recurrence to some of the leading and most generally received speculations of our schools, at the present day, upon this important to- pic of medical philosophy, which will be contained in the two following chapters : I am aware that the most authoritative maxims of logic, as well as every principle of correct philosophising generally, require, that in offering new theories for the expla- nation of a series of phenomina, we should not on- ly demonstrate a perfect reconcilability of our own positions to those phenomena, together with a tho- rough adequacy to their elucidation ; but that, at the same time, we also expose some palpable repug- nance to, or incompatibility with, those phenome- na in regard to all other opinions. The importance of this double injunction seems not, at all times, to have sufficiently impressed the votaries of our pro- fession; and through the neglect of which, from a fondness for intruding our own notions upon the world, gentlemen have too often suffered their ima- ginations to supply, what a more dispassionate judgment, and a more labored investigation should 9 have pointed out or rejected. This would have pur- ged our schools of the multiplicity of speculations and intellectual vagaries, which have too often de- luged their departments, and for a time diverted the footsteps of rational inquiry from their proper channel. Having long weighed the force of the above remarks, I will conclude this first chapter, -containing a simple enunciation of the grounds upon which my opinion is predicated, by declaring, that I feel perfectly warranted in the belief that there is not a fact or circumstance connected with the pre- valence of yellow fever in any quarter of the globe, in any degree repugnant to, or contradicto- ry of, the position I adopt; whilst, of the old no- tions, some are too vague and irrevalent to deserve serious attention, and the rest fall vastly short of af- fording any satisfactory illustration of the subject. 10 CHAPTER II. Among the great diversity of conjectures which have been thrown out at any period of the world, on the subject of epidemics generally, I find but three which are seriously resqrted to at the pre- sent day, for the explanation of yellow fever. These are electricity, contagion, and miasmata, from vegetable and animal putrefaction. As it re- gards therefore, the To Theon of the ancients, astral influences, invisible animalcule floating in the air, a nitro-aerial spirit, corrupted by an aura from the earth, arsenical, bituminous and other mineral effluvia, and a thousand other superstitious follies and absurdities, they may be passed over as being too ridiculous to require any particular refu- tation; for I presume, that at this enlightened era of our science, their bare mention is sufficient to carry their refutation with it. It serves, however, to display in what total mysticism the subject has, at all times, been enveloped, when we are told that for the illustration cf a phenomenon, such a disso- nance of opinion has prevailed. It must leave the judgment of the young inquirer in perfect suspense, when he has learned, that with all the erudition and experience of his predecessors, their speculations should be marked by features so diametrically op- posite in their nature. I will now proceed to con- sider, separately, the merits of the three opinions of the day, above mentioned, in as concise a man- ner as tl^r nature will admit of. 11 SECTION I. THE DOCTRINE OF ELECTRICAL INFLUENCES. So tar as I can learn, there have but three at- tempts ever been made of an express character, to prove the origin of diseases from the agency of the electric fluid. As the views of their authors were somewhat different, I shall consider them, individu- ally, according to the order of time in which their productions were given to the public. The first, therefore, whose notions demand attention, was the Abbe Bertholon of France. Having minutely ex- amined the effect of this agent upon muscular mo- tion, digestion, secretion, &c. in the human body, he arranged all diseases into ten classes ; some of which originating from a vitreous, whilst others were dependent upon a resinous electricity. He supposed the seat of these two fluids to be the at- mosphere, and that they were absorbed, into the system, through the pores of the skin. Their ope- ration, he contended, consisted in some direct exer- tion upon the nervous, muscular, and secretory sus- ceptibilities of the several organs, whereby digestion became enfeebled, its proper sympathies deranged, all the natural and vital functions disordered, and thus the foundation of diseases laid. But the insuf- ficiency of such an hypothesis must, I presume, be rendered perceptible by the following considera- tions : The doctrine is, in itself confessedly assump- tive, and is therefore unsupported by any direct ex- periment. And I am confident, that any observa- tions and reasonings, which he has adduced, either of a direct or analogical nature, have not been founded upon established principles of physiology, nor upon the visible symptoms of diseases. With- out which requisites they cannot be brought into c om - petition with demonstrations made to the senses, 12 From any thing, we at present know of the animal economy, of the phenomena of disease, or of the ope- ration of physical agents, generally upon the living system, I discern no reason, in nature, nor is there any legitimately assigned, why the effects in ques* tion might not, with equal propriety, be referred to! any other power, as to that of electricity. We should expect some unequivocal facts, either expe- rimental or natural, showing this to be its tenden- cy. He should have furnished us with some signs or appearances of the times, whereby we might be informed of the circumstances which favor an accu- mulation of a vitreous, or of a resinous electricity in the atmosphere. We should have had some ex- position of the reason why innumerable maladies prevail at the same place, and at the same time, dif- fering essentially in their symptoms, progress, sen- sations, treatment and consequences. Nor is there any attempt whatever, made to point out the falla- cy, or inadequacy of the causes usually assigned. This mode of conducting our speculations, certain- ly cannot be reconciled, without doing violence to the first principles of enlightened philosophy. Am- ple proof is exhibited on the face of a thousand fa- miliar observations of the day, together with innu- merable facts recorded in the annals of our science, that a sufficient number of obvious, as well as de- monstrable causes are constantly, and every where present to produce all the affections attributed to thjs far-fetched power; causes which are highly compe- tent to the end, and supported by the most rigid ana- logies drawn from all that is yet known of the philo- sophy of medicine, and of animal nature. That sudden changes of particular habits; debauchery j after extreme abstinence; violent exertions after long fasting; sudden exposures to a hot sun, and other vicissitudes of weather \ specific contagions, V3 such as syphilis, small-pox, &c. can, and actual- ly do excite a multiplicity of disorders; and that too under circumstances unaccompanied with the slightest evidence of an electrical influence, I think are positions, so universally received, as to require nothing farther in this place in their behalf. If what I have advanced be true, I should therefore con^ elude that, any necessity for an invisible, gratui- tous, and supposititious something to aid us in our enquiries, must be wholly superceded by more inj telligible powers. About the year 1800, and subsequently to the promulgation of the foregoing opinion, Noah Web- ster, of this country, published an elaborate trea- tise, written for -the express purpose of showing that all epidemic diseases could only be accounted for by some unknown operation of electricity. And after much research, thought he had placed the point beyond all farther controversy. He con- tended that meteors, volcanic eruptions, earth- quakes, &c. are unequivocal signs of a disturbance in the electric fluid, which he held to he extended throughout space, and to constitute what Newton called ether. That during such disturbance, this fluid, as a natural consequence, becomes unequally distributed in the atmosphere; being deficient in some portions and excessive in others, thereby ei- ther corrupting or changing the constitution of the air, or directly affecting the nervous sympathies of the body, lays the foundation of those diseases. He presumed that they might be divided into two classes of high, and of low action, depending upon an excess or deficiency of this hidden principle. As it regards the primary and immediate action of the electric agent, his notions do not essentially differ from the preceding, except that while he con- fines it entirely to epidemic diseases, the Abbe cm- 14 braces under his, every malady to which the hu- man system is liable. But when we come to con- sider the results of concomitant investigations, with which his doctrine seems necessarily connected, or rather upon which it essentially rests, it appears to me tenfold more pregnant with assumptive data, false arrangement, and absurd inference, than that of Bertholon's. For here we are required to wade through a series of the most perfect assumptions in order to arrive at his main principle; which last has nothing, either of an extrinsic or intrinsic nature to support it, except what it derives from the data so assumed. He supposes, 1. The immensity of space to be filled with the electric fluid, as a necessary atmosphere for the pro- pagation of light through the distant parts of the planetary domain. 2. That this fluid is the soul of the material world, whereby all impulses, connected with natu- ral events, are made. 3. That all violent convulsions in nature, such as tornadoes, earthquakes, volcanic eruptions, ex- cessive seasons, epidemic mortality among the brute, as well as human creation, are concomitant and immediate effects of a disturbance in the ordi- nary distribution of this fluid. 4. That comets, meteors, planetary aspects, &c. may influence this distribution, after some certain unknown manner. 5. That the human body, in common with eve- ry other part of the terrestrial creation, may become charged with an excess or deficiency of this impor- tant principle. 6. And lastly, that this excess or deficiency ac- tually lays the ground-work of all epidemical af- fections, by some how disordering the nervous, and other susceptibilities of the system. 15 In addition to the difficulties and objections, which I have already mentioned as necessarily ly- ing in the way of the doctrine, under any view of its features, I would here remark, 1. That to give any respectable force to his ideas, every principle of common sense demanded of Mr. Webster, some proof, either from experimental re- sult, or from rational demonstration, of the truth of his suppositions. 2. It was incumbent on him to show that no other causes existed, to which the phenomena might, with equal propriety, be attributed ; which has not been done, except by mere surmise. 3. He should, at least, have rendered it plausible, that earthquakes, long droughts, &c. might not be produced by other agents, already admitted on as high philosophical credibility, as that of the electric fluid, in giving rise to disease. 4. I discern no cogent reason for the limitation he has given to the action of this agent, by confi- ning it to particular maladies, while death equally ensues from other admitted causes. Upon the face of the universality, and immediate importance of this fluid in every natural event, it becomes difficult to conceive why it should so exert itself upon ani- mal nature, as to produce epidemical disorders, ■and no other. For we do know, that during the prevalence of those very epidemics, a thousand other affections occur of an entire different type; and if symptoms be the criteria, not at all referable to electricity, in any manner whatever. 5. Admitting that either a plus or a minus state of the electric fluid be adequate to the production of those diseases, the theory would still be extreme- ly defective, unless we were informed of some de- monstrable criterion, whereby this super-abundan- «*■>', or deficiency might be determined at any par- 10 ticular period to exist. So far as I am acquainted with the phenomena of natural electricity, as well as with authentic accounts of pestilence at large, I feel warranted in affirming, that it has prevailed over and over, not only in all its forms and stages of malignity ; but also under every variety and modification of appearance, presented either by the natural or artificial efforts of the electrical fluid. It appears to me therefore, clearly manifest, that Mr. Webster's notions rest upon speculations too far- fetched and conjectural to entitle them to profes- sional confidence. Dr. Shecut of Charleston, is the last individual^ who has expressly advocated the opinion in ques- tion. His notions being fundamentally identical with those of the gentlemen already adverted to, a few words may suffice for his case. I feel a plea- sure in doing his ingenuity the justice to say, that, however erroneous the hypothesis in itself may hereafter be demonstrated to be, he certainly de- serves all the credit which may be due for having reduced it to some more intelligible form than ei- ther of his predecessors have done. Confining the agency of electricity entirely to epidemics, he has advanced so far as to specify the particular disor- ders which depend upon an accumulation of the electric fluid, as also those which arise from its de- ficiency. He then speaks of what he terms an elec- trical equilibrium, which supposes some medium natural quantity. It is further contended that, while this equilibrium exists, the door is closed against the prevalence of epidemics. The natural signs of a destruction of this healthy or innocent state of the fluid, consist in much thunder and light- ning, or their total absence, &c. This powerful agent is presumed to effect its purposes upon the animal economy, ultimately, by some how gene 17 tilting a gaseous poison in the atmosphere. Which poison is supposed to disorder the healthy energies of the system, either through the function of re- spiration, or by a direct action upon the olfactory nerves, and in that way produces disease. In addition to what has already been preferred against the general agency of electricity in derange- ing the functions of animated nature, I have little to offer as to Dr. Shecut, except a few remarks founded upon some trivial modification arising out of his specific details. In addition to the unsupport- ed conjectures, and erroneous inferences which are essentially interwoven throughout the tissue of the hypotheses of Bertholon and Webster, the Doctor, as if aware of their fallacy, has attempted to furnish them some support by simply connecting one more link to the chain. Instead of stopping where those gentlemen did, in referring all the effect to the direct and immediate action of the electrical fluid, he con- ceives it better able to effect its purpose through some intermediate power. A defect which is enormous, as well as obvious upon the most superficial view of such an idea, is, a total absence of all explanation of what this gaseous poison is supposed to consist. Certainly, if it be a real existence, it must exist af- ter some manner; it must have some mode or con- dition of being, and is therefore tangible or demon- strable. If it be demonstrable, it must be simple or compound, and is therefore the result of some specific process. He somewhere vaguely speaks of a possible super-oxygenation of the air, as being the probable mode of the operation of electricity, in exciting certain affections. But this has not only not been proved to be the fact, but is directly re- butted by the most cautious results of eudiometric chemistry, as also by every experimental demon- stration of the philosophy of its action upon the e IS constitution of the air itself. On the highest mOUrt«* talis, and hi the lowest vallies, during every season and condition of the year, its constitution, and the proportion of its proper ingredients, are invariably the same. N jr is there any tendency to an excessn e state of the oxygenous portion of the air, ever dis- coverable by the action of electricity upon that fluid during any of its artificial applications. He also, in what lie offers as aphorisms on the term miasmata, speaks of a variety of specific gaseous poisons; some are entirely vegetable, some animal; from which he deduces a hydrogenous poison, an azotic poison, an amouiacjl poison, &c. together with various combinations of these. But when we come to make any analysis of their substance, or to institute any comparison of their in-.^ort with the true phi- losophy of decomposition by putrefaction, as con- tained in our best and latest chemical authorities, their perfect vagueness, as well as repugnance to experimental ic >ult is so very striking, as to set aside the necessity of any farther refutation. I would therefore ask, what it is that constitutes this gaseous poison which gives rise to yellow fever ? Does it consist of tlie electric fluid united to oxygen, or with nitrogen, or with the air itself? Does any one gaseous product of decomposition, or all of them together, united to electricity, form it ? Nothing 01 the kind is explained, or enforced in a manner afr all intelligible. I have deemed it proper to say thus much in refutation of this entirely hypothetical and unsup- ported doctrine, by leasori of the celebrity of it*; original promulgators, as also of the acknowledged learning and abi'i.ies of certain modern commenta- tors and reviewers, who have thought it worthy of 19 SECTION II. THE DOCTRINE OF CONTAGION. The advocates of the doctrine of contagion, e* applied to yellow fever, contend for the exigence of some specific morbid matter, generated in the hu- man body, and most generally accompanying hu- man or marsh effluvia ; which when taken into the body, some how reproduces itself, and by emana- tion, produces the disease in others. It is thus said to propagate itself by contagion or infection with- out any extrinsic aid. That this matter may be- come fixed in blankets, old clothes, packages of goods, &c. and being thus conveyed to distant places and there exposed, is capable of exciting the disease in as high malignity, as at iis original seat. This is an abstract and declarative expression of their real tenets. Indeed, were we to credit all the stories which are told us of those instances "of fo- reign exposure, by many of the less qualified belie- vers in this fanciful principle, we should be con- strained to palm upon it a kind of self-accumulative faculty during its passage or confinement, which enables it to display its energies with renovated and redoubled fury, when again disseminated. But on a closer examination, we discover an im- portant feature in their system, which, though pretended by some to be unnecessary, is yet acknow- ledged by all to facilitate the operation of their contagious particles, in so remarkable a manner, as in nvy opinion, is sufficient to render the credibility of the whole very dubious at first sight. They all agree, that yellow fever is not conta- gious, except under particular circumstances; an as- sertion, which if true, would destroy one of the best; tested distinctions that was ever made in any science, viz. the distinction between contagious and non- 20 contagious maladies. Will any one be so bold as to assert that small-pox, measles, kine-pox, psora, syphilis, &c. require one situation or period in pre- ference to another before they can act ? They re- quire contact, or unequivocal exposure, and do they ever fail to take effect when these conditions have existed ? of does the one ever loose its pathogno- monic signs by being absorbed into any of the rest? I presume no such thing has ever been witnessed. But wrhat are the circumstances which are confess- edly necessary to render the disease in question con- tagious ? Upon minute inquiry, we find them to be highly hot, moist seasons, and places of most confinement, and where most putrefaction of every kind is constantly going on ; or, as I should say, wherever all the causes usually assigned, on the score of heat, moisture, putrefaction and confine- ment, prevail in a high intensity, there yellow fever may exist; and where none of these causes are to be found, there it assumes the aspect of a mild bilious affection. Can gentlemen be serious when they express themselves thus? Again, how often does it prove non-contagious, compared to its appa- rent occurrences in the opposite form? I answer, about ten thousand to unity. I allude here to his- tories which cannot be disputed on am grounds; and not to those perverted, distorted, exaggerated, and in many instances, almost fabricated cases, which I regret to believe have too often been resort- ed to in our profession to support a favorite hypo- thesis, or to heal the wounds made, by rigid de- monstration, in the falling pride of deluded imagi- nation. It is said, these ten thousand require to be brought into particular habits of life, states of the body, &c. before those particles, which were so in- dependent, clc spa rate and fastidious in the one case, can exert their envenomed acrimony. Without 21 going a step farther, it must be obvious to the weakest capacity, that there is not a malady to wnich humanity is liable, which may not by such reasoning, be asserted with safety to be contagious. If two persons in the same family be alihcted about the same time, with hepatitis, we have only to declare, that the one necessarily caught his com- plaint from the other; if but one have the disease, we then say the circumstances are absent, which might render it active in the other; and I ask in cither case, who could ever disprove our assertions? Common sense might inform all parties, that de- bauchery, intemperance, exposure, ccc. had occa- sioned the affliction in both; and this I apprehend would be the fact, totally unconnected with any common principle. If there exist certain genuine, contagious atoms, which give rise to yellow fever, I would respectful- ly ask, what is the nature of the change which they must be presumed to undergo in passing to, or assuming the harmless state? What natural agents are concerned in effecting the conversion, or in ori- ginally stamping upon them their properties? They are something, or they are nothing. If the latter, then they form not a subject for philosophic inves- tigation ; if the former, then, as has been said of Dr. Shecufs gaseous poison, they must be made of some kind of matter, and are therefore solid, extended bodies; and if solid and extended, it cer- tainly behoves the advocates of their agency to offer some other proof of the fact, than the bare circumstance that they are unable to explain the ef- fect without them. No man of common sense, « much less an accomplished logician, would coin- cide with me in saving, that because a phenomenon exists, and I cannot explain it upon the comnv.n- ly received data, I am therefore at liberty to asseri t% what I please about it, We perceive every night, a number of shining bodies in the starry firmament, called fixed stars; no mem has yet demonstrated their nature, texture, composition, or uses; never- theless, I cannot feel myself at liberty to pro- nounce them so many actual gas lights, designed to illuminate the distant skirts of the universe. How far this is the predicament of the advocates for the contagious nature of yellow fever, I leave to the candid inquirer to determine. I would observe, that a majority of the physicians of the present day stand strenuously opposed to the hypothesis, whilst it has not been adopted to its fullest extent in for- mer times, but by a minority of those who had seen most of the disease, and who were best qualified by previous acquirement to trace effects to their ap- propriate causes. And it will also be remarked, that- there is not to be found a writer on the subject whose experience wras respectable, who has not somewhere spoken of cases which were confessedly inexplicable upon the doctrine of contagion; or expressed a belief, that to render the disease charac- teristically contagious, other powerful extrinsic, causes w-ere invariably requisite, I think I should be safe in asserting, that in all those cases where the disease has seemed to propa- gate from one person to another, were we to exa- mine the history of this latter, it will be found to have been amply exposed to all the causes, which are known to be competent to produce the high- t grades of bilious fever to which yellow fever is uni- versally admitted to bear the most striking simili- tudes. I regret that those who have taken it upon them to record histories of the malady, -have not at all times been as minute as we could desire ; but I think, on a fair investigation, there will be found the most satisfactory proof of the correctness of the 23 above position; although much allowance be made, in relation to the cases we have handed to us, for the distortion of facts, and suppression of circumstan- ces, by gentlemen in their advocation of favorite sentiments with the vindication of which they have falsely conceived their judgment and reputation concerned. In addition to the foregoing, I may assume it as a truth, supportable upon the highest authority, that in every instance when a person laboring un- der yellow fever, has been removed to an elevated part of the country where none of the generally supposed causes operate in a high intensity, the symptoms have all ceased with the individual pa- tient, without in any way having affected cither physicians, visitors or attendants: facts which are incontrovertibly established in my estimation by the best authorities; and which are totally irrecon- cileable with any such idea as that of specific con- tagion. I will not encroach farther upon the in- tended limits of this essay by quoting cases in refu- tation of this doctrine; it having heen already done in such an able manner by Caldwell, Rush, Ban- croft and others, as to render such an attempt on my part perfectly presumptuous. I feel constrained however to remark, that but for the writings of one man, I cannot think there would have been found a liberal physician at this day, in the belief of such a principle. And by comparing his statements with those of other men, whose talents and opportuni- ties were at least equal to his own, we discern much evidence, either of a destitution of candor, or that his understanding wTas extremely liable to be bewildered and his judgment led astray by ap- pearances, which it were unpardonable not to have penetrated, especially when about to found upon them a theory which involved so many important &I. consequences to the philosophy of medicine, a$ well as to the usages and interests of society at large. 25 CHAPTER III. •the doctrine or THE direct influence of miasmata. This opinion consists in attributing yellow fe- ver to a directly deleterious operation of marsh ef- fluvia, and other products of putrefaction, on the system. It is upon the overthrow of this notion, that the validity of my own must ultimately rest; for such is the nature of the facts adopted in each, that if one be true, the other is necessarily false- It is important here, that we distinguish between power and cause. For on this distinction rests, not only our ability to embrace all the circumstances concerned; but also much of the force and efficien- cy of our reasoning from the data so embraced. By a cause, to which an effect is referable, can only be understood the sum total of power concerned in its production. But such is the physical organiza- tion of material nature, that many powers may com- bine their tendencies to a particular end, while nei- ther, separately, would be adequate to its accom- plishment. Now, as no one of these powers, but the whole together, constitute the cause, common sense would tell us, that in explaining the effect, we should include the whole, in order that we might assign to each its appropriate character and influence. Indeed to select one, to the exclusion of the rest, would be to take such a partial view of the matter, as is strenuously forbidden by every sound principle of induction. That marsh effluvia, or the gaseous exhalations, which arise from vegetable and animal matters du- ring putrefaction, under a hot sun, do exert an in- fluence in the production of yellow fever, and that to a considerable extent, I would not pretend to D 2d deny. Indeed, I think their agency almost neces* sary to that effect. But I shall attempt to show, that to the doctrine as it is advanced, the following objections stand demonstrably opposed, viz. 1. That it adopts only one of a number of pow- ers, each of which is equal, if not superior to itself, and all alike essential to the process. *'" 2. That in the explanation of its mode of action, principles have been resorted to, which are directly contradicted by observation and experiment. I will now proceed to substantiate these objections on the double ground of reason and experience. The first may be referred to the next chapter, in which will be found, a specific exposition of all the powers wnich I presume to be concerned in the excitation, or rather in laying the foundation of the disease. The second will be the subject of the present chap- tec, viz. Th it, admitting a considerable extent to the operation of marsh and other miasmata, the com- mon illustration of that process, is so much opposed to the clearest results of observation and experiment, as to entitle the theory to the appellation of a mere hypothesis at best, and nothing more. No one disputes that, without a constant supply of oxygen gas, or atmospherical air, plants, as well as animals, invariably die in a very short time. It is also true, that when the processes' of vegetation,- and animal respiration, are conducted in closed ves- sels, the oxygen disappears, the subiect dies, and a product is obtained which is incapable of support- ing any life whatever; for all living matter immedi- ately dies when immersed into it. This product is a gaseous body termed carbonic arid. But will it be said here, that the death of the beings submitted to experiment, ere to he attributed, in any manner,, to this product, ouch less to a directly deleterious operation ? I presume not. If a substance is pro* 87 ved to be absolutely, and exclusively necessary to a particular process, is it not a most natural inference that, if that substance be withheld, the process must cease? Is it at all necessary to suppose any product of the process, requisite to effect its cessation? I fancy not. It seems then to be essential to vitality, that, so far as atmospherical air is concerned, its oxygen be consumed, and carbonic acid be a result, merely springing out of such consumption. What then is the source of death, or the cessation of the living process? Most evidently, the absence, or con- version of that important pabulum of life, the oxy- gen ; whose abstraction, upon the principle just laid down, is highly adequate to that end, without a requisition to refer any part of the effect to the car- bonic acid. The logical bearing of these remarks, which are founded upon the nicest experiments, should be well attended to; for in that we shall be enabled to distinguish between a true and a false cause ; between a necessary and an extrinsic power, in the production of effects : A distinction which is of invaluable moment in every investigation, where the connexion between effects and their cau- ses are at all complicated; or where actual appear- ances are contravened to negative operations. Let us now inquire what those noxious gases are, to whose action so much evil has been attributed; and whose origin consists in the decomposition of anir mal and vegetable matters by putrefaction. In this research I know of no source which is likely to af- ford any clue to our object, but chemical analysis; the philosophy of that science, whose energies em- brace all physical truth, and whose practical appli- cations to the comforts and ornaments of man, from their extent and diversity, have already given it an ascendency over every other topic of human intel- lection. We will commence this enquiry by sta- 28 ting what material bodies and circumstances are ab- solutely essential to every putrefactive process of the kind, to which I am alluding : These are, 1. Animal, or vegetable matter, or both. 2. Moisture, or water, either belonging to those substances themselves, or from extrinsive sources. 3. Atmospherical air. 4. Heat; and during yellow fever seasons, in a degree ranging from 80° to 95°, most generally. Without which requisites putrefaction neither com- mences, nor continues. The natural and chemical constitution of the above materials, as ascertained by specific investigations, are as follow, viz. 1. Animal matter affords, by analysis, four bo- dies, who^e simplicity entities them to the appella- tion of elements; for no experimental measures, hitherto instituted, have been adequate to their de- composition, or to render them more simple. These are carbon, hydrogen, nitrogen, and oxygen. 2. Vegetables are composed of carbon, hydro- gen, and oxygen ; and some contain a little nitro- gen; as furnished by the same processes, as the above. 3. Water is a compound of oxgyen and hydrogen. 4. Atmospherical air is formed of oxygen and nitrogen. These, with heat, being elements, are the only ingredients, ever alledged to be concerned in the formation of those effluvia, to which the disease has been attributed. They, therefore, either in a free state, or somehow newly combined, are the only products which we can legitimately anticipate to be found in the atmosphere; and such, upon ob- servation and analogy, may be well demonstrated to be the case. At this stage of our inquiry, it may be asked, by what kind of agency is an entirely new set of 29 compounds formed from the before mentioned ori- ginal maicrials, and what is its manner of action ? An answer to this question, embracing a complete experimental and philosophical exposition of its sub- ject, would require a digression into the science of chemistry, incompatible with the intended brevity of this treatise ; and, as I think, unnecessary to my purpose. Common sense, however, would sug- gest to any one, ordinarily versed in the phenome- na of chemical action, that before any new combi- nations could take place among the substances pro- perly within the sphere of action prescribed, the af- finities, by which the original compounds were held together, must be broken up. This may be effec- ted, either by the direct agency of heat ; by what is termed disposing affinity; or by both conjointly. The initial effect of a physical exertion of heat up- on bodies, is a separation of their particles, by which their attraction, for each other, is 'proportionately diminished. If at the moment of such separation, there be present a set of v:-\ tides of a different na- ture, the two sets may uniic and form new products, which, but for this agency of heat, might never have existed. The propriety of the term disposing affinity rests on the fact, that two bodies v. hi often refuse to unite, unless one of them be previously united to some third body. So that in the case be- fore us, a species of chemical energy may be tinci excited into action, and form binary, ternary, ecc. compounds; which energy might never have been brought into play, but for the presence of seme third product, also, disengaged at the same mo- ment. These remarks will facilitate a conception of the following rationale of the formation of the \uriovis products of putrefaction, under the condi- tions prescribed in a former paragraph. Though not professed to be complete, it is sufficiently sup- 30 ported by actual experiment, as also by many pro- positions, which are analogically established, respect- ing the laws which the gases in a nascent state, ob- serve in their action upon each other, to meet the intention with which it is here drawn up. We have, then, only four simple elements, viz. 1. Oxygen of the air—of the water—of animal, and of vegetable substances. 2. Hydrogen of the water—of animals—and of vegetables, 3. Nitrogen of all animal ; of some vegetable matters, and of atmospheric air. 4. Carbon of all animal and vegetable bodies. Now, if we suppose all those elements to begin, to be disengaged, simultaneously, we may easily conceive that a portion of carbon may unite to a portion of oxygen, and form carbonic oxyde gas. That another portion of carbon may receive an ad- ditional dose of oxygen, and form carbonic acid %as. A third portion of carbon may, by its affi- nity for hydrogen in a nascent state, form with this body, carbureted hydrogen gas. A portion of ni- trogen may unite to another portion of hydrogen, and form amoniacal gas. Another portion of ni- trogen gas, by its affinity for oxygen, may combine with a portion of this, to form the nitrous oxyde viency to the purposes of animal, life, require expla- nation, viz. 1. The disappearance of atmospherical oxygen. .. 2. The formation of carbonic acid. 3. The origin of the carbon. I. The dark color of venous blood, 5. The bright scarlet of arterial blood. 6. The necessity for the change, and, '?■ The manner in which it is effected m *£h& following considerations may lead to a just conception of the whole business : 1. The blood, as it goes to the lungs, bears a, dark, grumous aspect. 2. The air which is inhaled into the lungs, at the same instant, loses its oxygenous portion, and re-; ceives, in its stead, nearly an equal bulk of carbon- ic acid, which, with some aqueous vapor, and the original nitrogen of the air, is expelled at the next exhalation.- 3, At the self-same moment the blood becomes, of a bright scarlet, which it again loses during the circulation, whence it returns to the dark color above-mentioned. 4. If this process be. stopped, the animal imme- diately dies. These are topics of high importance to the philosophy of this wonderful function of animal respiration; and upon which much talent has been exercised, much laborious research instituted; and many ingenious speculations masterly conduct- ed. They all, however, with their respective mo- difications, resolve themselves into this alternative, viz, either, that oxygen gas actually enters the cir- culation, and mixing with the blood, some how forms carbonic acid during the rout, which is dis- engaged by the lungs; or that this oxygen never goes into the system at all, but merely abstracts car- bon from the blood as it passes through the lungs, and that" the formation of the carbonic acid there takes place, and no where else. To state it more ex- plicitly in the form of a query; does respiration sup- port life by furnishing an inlet to some necessary principle, 'oxygen, from without; or does it accom- plish that important end by facilitating the outlet of some surplus matter, carbon, which, if suffered to accumulate in, the system, might destroy life? *Jfr« is fairly the question now in point. My rea- t u ^ns for adopting the latter member of the aBov& alternative, may be drawn from the -following pro- positions, whose correctness is founded upon actual Experiment and calculation. 1. Tile carbon of the carbonic acid did not eS- ist in the air inspired, and therefore must have been derived from tlie blood while it passed through the lungs. 2. By a precis analysis of the carbonic acid produced, we obtain cvecy particle of the oxygen which essentially entered into the composition of the air breathed. 3. finery particle of the atmospherical nitrogen returns unchanged either in quantity or quality^ Except what arises from the carbonic acid, and aqueous vapor before spoken of. 4. Neither loose oxygen, nitrogen, carbonic acid, rtor atmospherical-^sapgeff- has ever been detected in