CHAPTER I.

THE NEGATION OF ATMOSPHERIC CONTAGION FROM THE HISTORY AND ACTUAL OBSERVATION OF DISEASE.

Ce qu’il y’a d’extraordinaire c’est que ceux qui fatiguent leur raison pour lui faire rapporter de certains événements à des vertus occultes n’ont pas un moindre effort à faire pour s’empêcher d’en voir la véritable cause.

MONTESQUIEU.

It has been attempted, in the preceding part of this work, to prove, on general principles, and by a reference to analogous objects, that atmospheric contagion cannot exist; but, lest that object should appear unaccomplished, and that the data are insufficient for the conclusion proposed, it is purposed to test the merits of the question by the consideration of the history and phenomena of disease.

Those circumstances, connected with the appearance and propagation of disease, on which the doctrine of atmospheric contagion rests, will be inquired into, and their weight and importance duly ascertained. This inquiry will be prosecuted as if no such investigation as the preceding had been made, and as if the existence of that agency was not irreconcilable with well ascertained laws; and, for the sake of argument, the possibility of its existence will be conceded.

The facts in the history of disease, which are held as lending countenance to the doctrine of atmospheric contagion—of proving its existence, are, chiefly, the general prevalence of disease at one and the same time among the members of the same family, of the inhabitants of the same town, district, and country,—its affecting the visitors and attendants of the sick,—and its observation in places hitherto healthy, shortly after communication with those ravaged with the distemper. These facts cannot be denied; and all that can be done is to weigh their value, as proofs of the existence of atmospheric contagion, and the first mentioned will occupy our attention.

THE EVIDENCE DRAWN FROM THE WIDELY SPREAD AND SIMULTANEOUS PREVALENCE OF DISEASE, IN FAVOUR OF ATMOSPHERIC CONTAGION, CONSIDERED.

The widely-spread prevalence of disease at the same time among the inhabitants of a country or district, is almost invariably held as affording proof of the presence and operation of atmospheric contagion.

The ravages of pestilence, rapid, wide, and deadly, are noticed in the histories of all nations, and at intervals they have been experienced during the long period of the existence of the world; and the destruction of whole armies, and the annihilation of entire nations, prove how widely spread its operation has sometimes been.

Did the circumstance of disease being widely spread prove its propagation by atmospheric contagion, then the matter were at rest; but the propriety of such an inference is questionable.

Let it be supposed that there is prevailing, in a district of country, disease to a great amount, that is to say, many cases of the same distemper.

That single circumstance proves nothing in reference to atmospheric contagion, more than to any other probable cause of disease. It shews, merely, that there is in wide operation some cause or causes of sickness; and it is totally unwarrantable to conclude that one agency, more than another, is the efficient cause, without further information directly bearing on the subject.

It is with the knowledge of the single fact, and in total ignorance of others, or with total blindness to them, that atmospheric contagion is pronounced to be the active agent.

Now it is not the peculiar property, the exclusive prerogative of that principle, to cause disease; at least, that character has not been openly sought by its advocates, though the tone of common conversation, and of medical writings on the subject, would seem to imply that it had been tacitly granted.

That cannot be conceded. Many other agencies are known to be productive of sickness, and have, on many occasions, induced pestilence of a deadly character, that has ravaged in no despicable limits.

The isolated fact itself of disease being widely extended in the absence of particulars, after proving that some cause existed, should legitimately go to create a suspicion, that the cause or causes which had produced the first cases, and acted as the ordinary springs of the malady, were continuing to operate on other individuals. Such would be known to be capable of producing the effect observed, for the satisfactory reason, that it or they had already accomplished it. How much more wise, under such circumstances, it would be to suspect the continuance of that influence with the continuance of effects identically the same as it or they had already produced, than to call in a principle whose only evidence of existence was the presence of effects, the same as had been only a short time before produced by a different agency, and of whose removal or absence there was not a particle of proof.

But a little inquiry will, on most occasions, elicit the fact, that some pestiferous influences exist; and it will, in general, be soon enough to pronounce on the probable causes of a distemper after that investigation has been made.

Disease in general, unconnected with alterations in the texture of the organs, is neither more nor less than a derangement of the functions performed by the body; and as it partakes of a general or local character, so the disease is either local or general; and, as it relates to functions, more or less important, so it is more or less dangerous.

It must be obvious, that a machine so nicely balanced, so complicated and so exquisitely wrought as the human body, must be liable, on many occasions, to have its operations impeded and deranged; and, although sometimes said to be a little world of itself, still, it is dependent on surrounding agencies. It requires a pure atmosphere for respiration, food to supply the waste it continually suffers, and drink to appease thirst, and to take the place of the fluids that are constantly draining from it.

The human body is necessarily brought in contact with the external world; and many are the injuries it suffers therefrom, both directly and remotely.

The derangements of the functions of the body are in general owing to circumstances of an unwholesome character, for the most part relating to food, drink, the various steps in nutrition, the atmosphere, its temperature, dryness, moistness, purity, &c. &c., and chemical and mechanical agents, to whose action the body is exposed.

Were it not for the operation of unfavourable circumstances of the nature specified, a body in health, were no special interposition of the Almighty hand made, would go on in the healthy performance of its functions, till the frailty and decay, incident to old age, would overtake it.

In general those diseases which are observed to prevail to a great extent, and over a large tract of country at the same time, are so uniformly coincident with circumstances of an unwholesome tendency, connected with those agencies above referred to, that they appear at once to the candid and unprejudiced inquirer, to stand in the relation of cause and effect. Surely it should cause no difficulty, nor occasion any necessity for the calling in a principle, atmospheric contagion, without any other evidence, that those effects are occasionally found not confined to one spot merely, but are seen developed in an extended sphere—for, assuredly, it can require no extraordinary effort of the mind to conceive that the agent acting and causing disease in one place, or individual case, may with equal force, and with a like result, act in many situations, and in respect to many persons.

The presence of certain operations in several situations by no means proves that they have reproduced themselves.

Day-light is manifest in many countries, within certain latitudes at the same hour, but it has never been suggested that this circumstance in one of them has been propagated by that of another, through any occult principle, or whatever else such an agency may be called.

Had the case not presented at once, and in so direct and striking a manner, a sufficient cause for the effects observed, then we doubt not, that, perhaps, individuals would relieve themselves of any present difficulty, and attribute what they could not readily explain, to the operation of a principle having as little evidence of its entity as atmospheric contagion itself. But the sun is too glorious, too resplendent an object to be overlooked, and its effects are too immediate, to permit the possibility of the most unreflecting, not marking its relation as cause to the effect observed.

But, unfortunately, the relation between widely spread diseases or epidemics, as they are called, and circumstances connected with the agencies before referred to, is not so striking—though it is as close. There is no object so bright to draw the same attention to it, and to proclaim it from east to west, from the dawn of morning till the fall of evening, like that luminary dispersing light as he appears to traverse the heavens.

Yet there is room to believe that the presence of epidemics is always accompanied, or shortly preceded, by circumstances, which, though by reason of their less striking character, and less immediate operation, are sometimes overlooked or neglected, yet do exist, and, were inquiry made by those able for the purpose, doubtless would be found.

In most of the epidemics recorded, some such agencies or circumstances were in operation. They were known to be so—and in almost all that have come under our own observation, and they have neither been few nor carelessly noted—there have, on nearly every occasion, been found the influences to which we allude.

We are led to believe an agent to be the cause of an effect when the one follows upon the operation or presence of the other, uniformly, and on every occasion, when the latter bears some relation in its amount to the force and length of duration of the former—and when the effect ceases with the removal of the agent. Such a close connection, as subsists in that case, entitles the former or agent to be held as the cause of the effect observed.

For those very reasons day-light is said to be the effect of the sun that comes with it, remains with it, and goes with it.

Let us see if the same connection holds with disease and those agencies and circumstances we have cursorily referred to.

Those agencies and circumstances, relating to food, drink, air, heat, contagious matter, &c. &c. are known to present themselves, and with them are presented diseases. They are known to remain, and with them are known to continue diseases. They are known to disappear, and with them all the world knows diseases disappear also.

These being the causes of epidemic or widely spread disease, as such a connection proves, it is altogether superfluous to admit the operation of atmospheric contagion, whose existence has never been known, but by the very circumstances which it is said to bring about.

It is surely most unwise, when we see disease arising with the existence of unwholesome circumstances, such as scarcity of food, unwholesome quality of it, great vicissitudes of weather, uncommon conditions of the atmosphere, want of sufficient clothing or incommensurate with the severities of the season, the operation of depressing passions, and the like,—growing with their intensity—extending where they extend—abating where they decrease—and finally disappearing when they disappear—to refuse to grant the relation as cause and effect, and to plunge into the tide of difficulties such ill-timed incredulity creates, with nothing but the appearance, nothing but the assurance, of an object to grasp at.

In general, such a connection can be made out between the existence of wide-spread disease and such circumstances.

If, in respect to some diseases, so intimate a connection cannot be observed, the probability is, that it is the obscurity connected with these subjects, the less direct way in which they operate and the remote time at which their effects may be experienced on the body, that are the occasion of the difficulty. The human body, unlike mere inanimate matter, has the power of withstanding, at least for a time, the operation of unwholesome influences, if not very virulent; and it is only natural to allow, that, in respect to a machine so complicated, affected by so many agencies, and standing in so many relations, there will be less complete directness of operation, than with simple or inanimate substances, and more variety in the amount and duration of the effect.

On these accounts, the indications of the case are less direct and obvious, and it should cause no great surprise, that being considered, and the fact of the imperfect state of our knowledge on the varieties of the agencies referred to, being kept in mind, that the causes of disease cannot at all times be completely and satisfactorily ascertained.

Our knowledge of the derangements of health, from the operation of these agencies, on some of which we are dependent, and with others of which we are constantly brought in contact, is fast increasing, and the relation between the former and the varieties in the latter is becoming clear and precise. There is, therefore, reason to hope that difficulties which now baffle us, will soon be explained away, and that much of that mist that has long overhung the causes of pestilence, will soon be dissipated.

Certain circumstances produce certain uniform effects, and in every instance where they are operating, their effects will be produced, provided no agency is acting adequate to neutralize them. Not one hill only, in northern latitudes, has its summit whitened with snow, nor does sterility mark a few spots only in the immense deserts of Africa and Asia.

The same features are spread far and wide. They owe their existence to agencies acting in immense spheres corresponding with their own.

The sphere of those circumstances connected with the agents so often referred to, that produce disease, is sometimes large, and no astonishment need be felt, if that of disease is also large, since a relation ever holds between the extent of a cause and its effects.

It would certainly be ample time to call in the assistance of atmospheric contagion to account for the propagation of disease, when its sphere or circle is found to be positively eccentric of that of those circumstances alluded to.

But we are satisfied that such a contingency is of very rare occurrence, and even when it is said to exist, we shall require some undoubted assurance that the non-correspondence is not the result of ignorance of the extent of these hurtful circumstances, rather than the actual absence of relation between them.

It is not our intention at present to enlarge on the causes of disease, yet we maintain, that such a relation as that referred to, will in almost every instance be made out, if candid and efficient inquiry be instituted; so that, even granting that atmospheric contagion exists, there can be no room for its operation. And we are of opinion, that if, in some extraordinary instance, no such relation can be detected, the progress which every department of science is making will in time achieve what may not be accomplished at present.

The history of nations and the records of medicine shew, that, coincident with epidemic sickness, there have, for the most part, been noticed certain circumstances operating which were prejudicial to the welfare of the human body. For example, famine, bad or unwholesome food, great and long continued droughts, great rains followed by intense heat, sudden vicissitudes of weather, dissipation, irregularities, depressed state of mind, insufficient clothing and fuel, and unwholesome water.

These, and many similar circumstances known to prevail in the haunts of pestilence, must exert a great, a very powerful, influence on the human body, and, when the question of the probable causes of its diseases is mooted, it argues a strange and discreditable blindness to obvious facts, to overlook the part which they must exert in their production; and a strong and dangerous partiality to a questionable principle, to attribute the whole calamity to atmospheric contagion.