CHAPTER V.

CONTAGIOUS POISONS—NON-SOLUTION IN THE AIR—RESULTS OF EXPERIMENTS.

Animal substances are the results of still more delicate processes, and of a more refined organization (than vegetables); and the balance of affinities, by which they exist, is disturbed by still slighter causes.

HENRY.

For the present, the argument drawn from the actual observation of the origin and propagation of disease, against the doctrine of atmospheric contagion, will be waived, and it is proposed here, before going farther, to inquire, whether the case may not be settled by a reference to the history of analogous agents, and to the results of experiment.

It is proposed here to inquire if it is likely, judging from their chemical constitution, that palpable contagious poisons, such as the matter of small-pox, may be disseminated through the air, without chemical changes being effected upon them, that must be destructive of their peculiar properties.

The palpable contagious poisons are products of the blood, formed therefrom, by the nicest processes. They partake of the nature common to all animal products; are, like them, prone to putrefaction,—and, like them, are of a very compound nature.

They are animal products: now it is a well known fact that almost all animal products are fixed—that is, incapable of being volatilized or disseminated in air, unchanged in chemical constitution.

Gelatin or animal jelly; albumen, or what is much the same, the white part of an egg; fibrin or muscular fibre, and the like, are never known to be in the vaporic state, or commingled with the air. They are incapable of assuming the aeriform state, not in virtue of a character peculiar to them, but on account of that nature they share in common with almost all animal principles, which precludes the possibility of their being volatilized. No experiment has ever been made which can show that the principles specified may be diffused through the air.

When exposed to the air for even a short period, decomposition takes place, and their original nature is totally subverted.

Their elements are held together by affinities too feeble to admit of their particles being separated by air, without new combinations being formed.

If heat be applied to them, immediate destruction takes place; if they be kept moist, and in merely a moderate temperature, putrefaction or fermentation, in the proper sense of the terms, occurs; if carefully dried and exposed to the atmosphere, they remain little altered, for a considerable time; but at length fundamental changes, though operating slowly, entirely change their nature.

It cannot be shewn that contagious poisons are less animalized than the products alluded to.

Is it ascertained that contagious poisons, unlike other proximate animal principles, enter into the aeriform state?

Putting aside the loose and rash statements current upon the subject, as unworthy of notice, there can be no doubt that, in the whole history of those poisons, no fact is known, that can legitimately be held as proving, that they possess such a property, or of giving the idea any degree of countenance.

On the other hand, many facts are known, which are adequate for the refutation of these statements, and that are sufficient to put the case beyond a doubt.

Small-pox propagates by a contagious poison, eliminated from the blood, and found in the pox or pustule.

It is known to every one that it affects, by contact, hence the practice of inoculation, which is nothing more than the inserting, under the skin, a little of that agent, a practice which has been in use among the negroes of Africa, since, or before, the introduction of the doctrines of Mahomet.

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.

Footnote 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.

The plague, according to the very best authorities, is undoubtedly marked by the elimination of a matter capable of producing the same pestilence, when applied in a palpable form, to the body of another. The plague has been produced intentionally by inoculation, and may be propagated at pleasure.

Dr Patrick Russell was satisfied, from the observation of much of that pestilence, that the atmospheric contagion did not extend the distance of four feet; and there is much room to think that, if he had extended his inquiry farther, that had he been aware how unusual it is for a proximate animal principle, as contagious matter, to take on the aeriform state, he would have arrived at the conclusion, that it did not only not exist, at the distance of four feet from the patient, but that it did not exist at all. Had he gone that length, he would not have created any more difficulties, to be explained away, than were made by laying down for it, such a limited range of operation, for there would, it seems, be little difficulty, in general, in discovering, that persons who had approached so near as four feet to the patient, had come in contact either with the sick himself, or the matter of the sores attached to clothes or other bodies.

We know of no facts capable of proving that the matter of plague is diffusible through the air; and the very evidence of Dr Russell, which was used by him to prove the limited range of atmospheric contagion, may be used to lend countenance to the position, that it does not exist at all.

The evidence was this:—Dr Russell was in the practice, at Aleppo, of examining plague sores from a window four feet from the patient, yet he suffered not from that pestilence.

Scarlet Fever is a disease universally held to be one of those propagated by a contagious principle.

It is commonly believed that a contagious poison is eliminated in the course of this disease, similar to that of small-pox.

Its history is marked by this remarkable feature, peculiar to acute contagious diseases, of attacking the same individual only once; and the disease is accompanied by a peculiar eruption, which may, without impropriety, be supposed to contain the said contagious poison. This eruption is uniform in the time of its appearance, its duration, and decay, like the other eruptions of other contagious diseases. On all these accounts, the Author is disposed to assent to its possession of the contagious poison;—and that will be taken for granted.

Connected with this view, is an observation made by Dr Sidey, of Edinburgh, in a paper contained in a late Number of the Edinburgh Medical and Surgical Journal, on Scarlatina, as lately prevalent in that town. It is to this effect, that he found that the disease, when characterized by a distinct eruption, attacked several members of a family more frequently, than when it wanted that symptom.

We will inquire whether persons exposed to an atmosphere containing one sick of that disease, take that distemper as uniformly, as those take the respective diseases of those palpable contagious poisons which may be inserted under the skin.

During a most severe and mortal visitation of that disease in Tranent and its surrounding country, which lasted from about the end of January to the 20th October 1836, many cases occurred, where brothers and sisters of children suffering under that malady, living in the same apartment, but not sleeping together, remained free of any attack whatever at the time.

Had the poison been capable of diffusion in the atmosphere, the air would have become highly contagious, and as persons were constantly inhaling it, and among them some liable to the disease, it would certainly have manifested its peculiar pestiferous influence upon them.

But the result was different, and the person exposed at that time remained quite free of it; and in the course of time, varying from weeks to several months after, went through the disease in the ordinary manner. These cases have been carefully noted and preserved.

But the Author was anxious to ascertain, by other means, whether that disease was capable of propagation by atmospheric contagion; and opportunities were not wanting.

It occurred that the matter of ulcers, in the throat, might possibly contain the contagious poison, and might be made the subject of experiment.

The following is a case in which the experiment was made.

The patient, a boy eight years old, had been exposed about three months before, constantly, to an atmosphere in which a younger brother, ill of scarlet fever, was breathing.

He had the precursory fever, and the tonsils and uvula (the parts at the back of the mouth) were almost covered with ash-coloured spots and suppurating ulcers.

A piece of linen, fixed to the extremity of a probe, was rubbed freely over the ulcers. The linen impregnated with matter and the secretions, was, within an hour or two of its being taken, exposed to the free action of the air of a small apartment, where it remained for ten days, without producing any effect, upon several persons, a good deal in the room; and among them, two children, one aged two, and the other fourteen years, who had not had scarlet fever. They respired the air occasionally and for a considerable time, on the several days.

The temperature was various. During the day being about 60° Fahr., and 40° during the night. The linen readily became dry, but was repeatedly moistened with water.

This experiment goes to shew, that the matter of the ulcers of scarlet fever is incapable of propagating the disease, through the medium of the air.

But scarcely any better nidus could be formed, for the dissemination of the matter, of the ulcers, through the atmosphere, than the sores themselves, the very place where it is eliminated; and cases have been referred to, where persons have respired an atmosphere thus liable to be acted on, with the most complete impunity.

It is not ascertained that the contagious poison is eliminated at the sores in the throat, but such seems probable, seeing that the sores are as essential and constant as the eruption itself.

Experiments might have been multiplied, but that has appeared unnecessary, as it is hoped that enough has been done to shew that the contagious poisons which have undergone our examination, are incapable of assuming the aeriform state, and, as it must seem probable, that in a point so important, they will all coincide, even those which have not been treated of here.

Their chemical constitution, as before remarked, prevents their assuming that state. Dr Henry of Manchester remarks, when pointing out the distinctive characters of animal and vegetable bodies, that “Animal substances are the results of still more delicate processes, and of a more refined organization, and the balance of affinities by which they exist is disturbed by still slighter causes;” and again says, “Instead of passing through the vinous and the acetous fermentation, they are peculiarly prone to undergo putrefaction.”

Thus, then, this great law, ascertained and settled beyond a doubt, and the results of our observations on the causes of diseases styled contagious, and of experiments on the palpable contagious poisons themselves, are opposed to the admission of this doctrine, and when we recall to memory the slender evidence, nay, the absence of any evidence at all, the conclusion almost necessarily is, that atmospheric contagion does not, and cannot exist.

With what justice may we now join with De Lolme, when he says—“There is a very essential consideration to be made in every science, though speculators are very apt to lose sight of it, which is, that in order that things may have existence, that they must be possible.”