CHAPTER IV.

THE ABSENCE OF SUFFICIENT EVIDENCE OF THE EXISTENCE OF ATMOSPHERIC CONTAGION.

Ponderable bodies are endowed with common or general properties, and likewise with particular or secondary properties.

MAGENDIE.

The properties of atmospheric contagion, under its various titles, have been noted in the preceding chapter. They have been attributed to it, by the most eminent writers on the subject, and are such as are assented to, by most medical men of the present day.

Its origin, the sphere of its activity, and the means by which it may be destroyed or neutralized, have there been alluded to. In the extracts given, and in the current medical literature of the present time, it is spoken of, as an agent of whose existence there is the utmost assurance.

The reader who has not already thought upon the subject for himself, but has, as is almost universally done, in reference to this agent, taken the whole case, as one fully ascertained, and settled upon fixed principles, will doubtless be surprised to hear, that it is the decided opinion of a member of the medical profession, that the doctrine of atmospheric contagion presents no sufficient evidence of its truth; that he is in possession of facts connected with the occurrence of disease, which render it probable, that other and efficient causes of disease have been thrown aside, to make room for that agency, and that he is convinced, from the results of experiments on contagious poisons, and from a minute inquiry into their nature, that it (that is, atmospheric contagion) does not exist. Perhaps he should regret that he has not been able to see the question in the same light as his brethren. He has felt unwilling to espouse singular opinions; he has therefore been patient in the inquiry, and it has been only from the consideration, that a great medical truth was concerned, that the progress of the science might possibly, thereby, be promoted, and that the comfort of the patient, and the ease of mind, of the public, might be advanced, that he has been induced to lay his opinions before the world.

Regarded as a physical agent, atmospheric contagion has never been detected, and its presence has been inferred merely from the observation of what have been supposed its effects. It has certainly never been unequivocally manifested to any of the external senses. It has never been seen combined with the atmosphere, precipitated from it, or attracted therefrom, to solid bodies.

It might be supposed, however, from common parlance, that it has often made itself known to the sense of smell; but while nothing certainly proves that the impressions made on the nasal organ arise from atmospheric contagion, many circumstances induce at once the belief, that they proceed from common impurities.

The atmosphere in a sick chamber sometimes certainly has an odour, but it is certainly more logical to attribute this to the presence of impurities, whose presence there is no room to doubt, than to an agent whose existence under any circumstances has never been proven.

Had contagious matter the power of diffusing an odour through the air, it is probable, that would be constantly the same, in all cases of the same disease, and that each disease would have its own peculiar odour: but this correspondence is not found.

It is not desired to prove, that atmospheric contagion does not exist, because it cannot be detected by the senses.

Many agencies exist, which, under ordinary circumstances, are beyond the cognizance of the external senses; but in general they make themselves manifest to one, or other, under some conditions. The electricity of the air is neither seen nor felt under ordinary circumstances; but that agent is capable of being collected from the atmosphere in such quantities as are cognizable to the eye. Now, under any manner of circumstances, contagion has never been recognised by the senses—and it has never been detected by chemical experiments.

It is surely not unfair to expect, that, if a contagious poison, a palpable matter such as is contained in a small-pox pustule, is transformed to the vaporic state, or taken into the atmosphere, that the air so impregnated will be marked by some qualities, beyond those of simple, pure air. Perhaps air in which it is disseminated should have an odour, and perhaps that odour should be of a peculiar kind, in each disease. Should it not also be marked by some effects, constant and uniform, upon the human body, such as mark the career of such like agents in a palpable form, when applied either immediately, as by touch, or mediately, as by fomites? Perhaps it may not be deemed unreasonable to expect, that atmospheric contagion, did it exist, would produce its peculiar effects, as constantly, or nearly so, as a palpable contagious poison. But how different is the fact. If a hundred persons not formerly vaccinated, have the palpable contagion of cow-pox matter inserted under the skin, the probability is, that, if the matter is good, and the operation is skilfully done, 90 or 95 will be duly affected with the specific effects; whereas, when a hundred persons are exposed to the atmosphere of fever, and when these persons, too, have not before had the disease, perhaps not one, or at most not above two or three will take the distemper, unless the air has become extremely vitiated; and then the probability is, that it is so, not in consequence of the presence of specific contagious virus, but of gross impurities, and the consumption of the more vital parts, as in the case of the Black Hole of Calcutta, where putrid fever attacked all who survived their confinement, certainly not from the action of contagious poison.