Many physicians, perhaps almost all, believe that it, the poison, may be diffused through the air, and in that situation produce its wonted effects; but evidence is submitted to shew, how questionable that is: and it is conclusive, as far as negative evidence can go.
The following experiment was performed by Dr O’Ryan of Lyons.[[2]] The force of its results, and their tendency, cannot be overlooked.
[2]. O’Ryan, Sur les Fievres.
“A dish containing lint saturated with matter taken from the natural and the inoculated small-pox, was placed upon a table, whose diameter was three feet, and children who never had the disease, and never were inoculated or vaccinated, were placed around it, and kept there for some considerable time; yet none of them were seized with the disease.”
“He also exposed children within two feet of a child affected at the time with the inoculated small-pox, for an hour daily, for fourteen days. None of the children were affected, and all were successfully inoculated two months afterwards.”
We are acquainted, too, with many cases of small-pox, where the houses in which they were, were visited by many persons, some of whom had not been vaccinated, or inoculated, and yet the disease did not spread to them; and in those instances, where the distemper did spread, only some, and not all, who were liable, were affected, as would have been the case, had the matter been inserted under the skin.
Perhaps, in reference to this contagious matter and to others, it may be said that they were not favourably situated for acting. Heat, moisture, and the passing to and fro, of air, must certainly assist the assumption of the aeriform state; and a more favourable opportunity cannot be obtained, than the contagious matter of small-pox pustules has, in the mouth of the patient, where it almost always is observed. That situation is perhaps even more favourable than that of the matter operated on by Dr O’Ryan. Yet it is known, (and we are prepared to shew cases) that persons liable to the disease have breathed in the same apartment, and have not taken the distemper. We know, too, of many cases, where persons have been attacked under such circumstances, but that has probably arisen from actual contact with the matter, or exposure to those general and widely-spread influences productive of that pestilence, that undoubtedly exist. But it is not necessary for our purpose, that all should escape, but, that any should not suffer. It is enough that those who escape, are more, in proportion, than those who resist the action of the palpable poison, when inserted into the system by inoculation.
With respect, also, to the disease produced by the insertion of cow-pox matter, or, in other words, by vaccination, as it is called; nobody ever heard of it being propagated through the air. It is feared that it would be a very inefficient mode of vaccinating, to bring the child to be vaccinated, into an atmosphere, to which was exposed an arm with a cow-pox. He who would propose such a plan would be laughed at by every old woman; and what is held as so absurd and ridiculous in respect to cow-pox, cannot be very wise in reference to small-pox, plague, scarlet fever, and the like. There are other diseases, too, which undoubtedly are propagated by palpable contagious poisons. Yet were any person affected with them, to whisper, that a contagious atmosphere had been the occasion, they would be held as using no small liberty with the credulity of the medical adviser.
There is yet another palpable contagious matter to which reference must be made,—that of itch. The only known way by which that disease can be propagated, from one to another, is by palpable or contactual contagion.
Many medical men are in the daily practice of seeing and examining such cases, yet they seldom or never are affected with it. Any caution directed against the operation of that contagion, is addressed exclusively to contact, never to the atmosphere.