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.