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IS IT PROBABLE THAT EPIDEMIC, ENDEMIC, AND INFECTIOUS DISEASES, DEPEND UPON VITAL GERMS FOR THEIR MANIFESTATIONS?

It is, I believe, almost universally considered that Epidemic, Endemic, and Infectious diseases, originate from some imaginary poisons of a specific nature, each disease having its own peculiar poison. That this conception should have taken possession of the minds of men, is most natural from the symptoms which characterize these diseases, but when we come to enquire into the nature of these agents, or supposed poisons, we are at once struck with the idea that they exhibit one peculiarity which separates them in a marked manner, from those poisons with which we are familiar; for the poisons of Small Pox, Measles, Scarlet Fever, Hooping Cough, Fever, &c. possess the power of multiplication, or spontaneous increase, a property which attaches only to the organic kingdom, and is never known in the inorganic kingdom. The source of most of the poisons is to be found among mineral or vegetable products. A mineral in combination with an acid or oxygen may become a poison, and nitrogen in various combinations with oxygen, hydrogen, and carbon, or with carbon alone, may become a poison; these combinations are, however, in most instances the products of vegetable life, others again are obtained from the animal kingdom, such as the poison of the serpent, &c. but in all of these instances, there is not one in which the power of self-multiplication is to be found.

We are, therefore, constrained to admit that this feature, which distinguishes poisons, is one well worthy attentive consideration. The varieties of poisons may be classified into those which act topically as escharotic poisons, those which act chemically on the blood, and those whose effects are manifested in inducing a speedy annihilation of organic or vital action, as in the case of hydrocyanic acid, which is supposed specifically to affect the nervous centres from which originate the vital manifestations. It is rather remarkable that the vital poisons (as I will call them for distinction), seem to have their appropriate locality in the blood, they do not primarily affect one organ more than another, all the effects we witness resulting from them are to be traced progressively from the blood to other parts of the body. When a person is inoculated with small pox, a very minute portion (indeed it is impossible to say how minute it may be) is sufficient, when absorbed, to excite a certain train of symptoms, all due to absorption of the materies of the disease, and the process by which that materies arrives at maturity, is that known in the vegetable world as the fructification; this process of fructification is a process of development and increase.

I here may repeat that among all the poisons known, constituted as they are of various combinations of elementary matter, they are without exception destitute of the power of development or increase. Now, it is pretty accurately known what amount of these poisons is necessary to produce their effects on the living body; we can say how many drops are sufficient of hydrocyanic acid of Scheeles strength, to destroy a man instantaneously. Again, how many grains of arsenious acid are sufficient to induce such an inflammatory condition of the stomach and intestine as will end in death, and how many grains of morphia, will bring about a fatal coma—but who shall say the amount of the vital poisons necessary to produce their results? It far exceeds the limit of conjecture, to what extent the dilution of miasmatic or contagious matter may be carried, and the poison yet be capable of committing in a short time the most frightful ravages.

We may fairly then infer, that if a quantity of matter inappreciable in amount be sufficient to exhibit the characters of growth and increase, that it is endowed with the properties of vitality. That the poisons of scarlet fever, of measles, and of small-pox have this power of growth and increase, is as much a matter of universal belief as that "the sun will rise and set to-morrow, and that all living beings will die."

This power of individual increase, or reproduction, is the very summit of vital manifestation; indeed Coleridge, in his Theory of Life, (in which he says, "I define life as the principle of individuation, or the power which unites a given all into a whole that is presupposed by all its parts,") places reproduction in the first rank, and expresses his hypothesis thus: "the constituent forces of life in the human living body are, first, the power of length or reproduction; 2nd, the power of surface, or irritability; 3rd, the power of depth, or sensibility—life itself is neither of these separately, but the copula of all three."

Extensive research is not required to shew that many thinking men believe in the existence of living organic beings, as the elements of contagious and epidemic diseases; the idea indeed seems to flow spontaneously in that direction. Whenever thought, and enduring contemplation, have been concentrated on the subject, the result appears to have been the same, a firm conviction in each individual mind that a vital force must be in operation; or as Schlegel would define it, "a living reproductive power, capable of and designed to develope and propagate itself."—"Its Maker originally fixed and assigned to it the end towards which all its efforts were ultimately to be directed."

Referring further to beings having the property of reproduction and propagation, he says, (using the word nature here evidently as the vital principle for want of a better term,) "Nature indeed is not free like man, but still is not a piece of dead clockwork. There is life in it."—"Thus we know that even plants sleep, and that they too as much as animals, though after a different sort, have a true impregnation and propagation."

When Schlegel wrote this, how little could he have imagined the intricacy of this proceeding among the lower forms of vegetation. It has been shewn by Suminski, and verified by many others, that the mode of impregnation, and the period at which it occurs in the ferns, do not at all correspond to the general notion on this subject. He has discovered in the early development of the frond of ferns certain cells, which he denominates antheridia, or sperm cells; these contain in their cavity a number of subordinate cells, each containing a spermatazoon. At a certain period of the progress of the frond, the parent cells become ruptured and liberate the spermatoza, these move about in a mucilaginous fluid, which bedews the inferior surface of the frond, and become the means of impregnating the germ cells, or pistillidia, with which they readily come in contact. Thus the process of impregnation in these plants occurs during the germination, or what corresponds to the period of germination in the seeds of exogenous and endogenous plants.

I have referred to the discovery of Suminski in this place to recal to the mind the great and incomprehensible wonders of creation, for who could conceive it possible or feasible that even for the impregnation of an inferior vegetable, animal life should form an indispensable and essential appurtenant of the process. Truly may we say with Coleridge, of plants and insects, "so reciprocally inter-dependent and necessary are they to each other, that we can almost as little think of vegetation without insects, as of insects without vegetation."

I will make but two more quotations on the supposed vital character of the germs of disease. "That the air and atmosphere of our globe is in the highest degree full of life, I may, I think, take here for granted, and generally admitted. It is, however, of a mixed kind and quality, combining the refreshing breath of spring with the parching simooms of the desert, and where the healthy odours fluctuate in chaotic struggle with the most deadly vapours. What else in general is the wide-spread and spreading pestilence, but a living propagation of foulness, corruption, and death? Are not many poisons, especially animal poisons, in a true sense, living forces?"—Schlegel.^[3]

It were useless to multiply quotations to shew that the opinions here entertained are matters of general belief among thinking men.^[4] I will at once then conclude with an observation of Dr. C. J. B. Williams: he puts the question, "Does the matter of contagion consist of vegetable seeds? Are infectious diseases the results of the operations and invasions of living parasites, disturbing in sundry ways the structures and functions of the body, each after its own kind, until the vital powers either fail or succeed in expelling the invading tribes from the system?"

And this expression, the seeds, is an universal expression, it is a "Household Word" in connexion with disease. That it has obtained this position in the popular vocabulary is alone a proof of the applicability of the term to the thing intended to be signified. Popular notions, as we have seen in the case of Jenner's discovery, are not to be unheeded. An instance occurs to me, it was a popular belief, that in acne punctata, the matter of a sebaceous follicle, was itself, when pressed out, a worm, the dark portion which results from the accumulation of dust upon the matter at the mouth of the follicle was supposed to be the head of the maggot, as it was called; subsequent observation, however, has proved that though this matter is not a worm, it contains an animal within its substance, the Acarus folliculorum.

The popular notions found among savage tribes as to the efficacy of certain remedies in the cure of disease have been the means of furnishing us with some of our most valuable medicines, indeed it is almost impossible to say whether originally man did not derive his remedies from the herbs and trees by an instinctive faculty impelling him, as it does the animals when in a state of liberty and with freedom of range, to seek certain plants as they avoid others.

It is well known that animals when indisposed will find out some spot as if almost led to it by a visionary guide where the "healing plant" is to be discovered. I am told that sheep have this faculty, and that they will, when affected with the rot, feed upon some plant when they can discover it, which eradicates the disease.

Almost every one is familiar with the fact that cats and dogs will crop herbage and eat it; I have seen them frequently leave the house and proceed to the grass in the most business-like manner, partake of some quantity, and quietly return.

A close observer of diseased animals might obtain some useful information by noticing the plants cropped by them while in that condition. The observations should be made in a variety of districts in consequence of the uncertain distribution of some even of the most commonly scattered plants; in one year they may be abundant, but in another they may be almost entirely absent from the same spot.^[5]

Were it only on the fact of reproduction, I would be contented to take my stand that the force of life is the indwelling power of pestilential matter. Reproduction is a law of nature, and the law of nature is the law of God. And where do we find He prevaricates with us? The more we study His laws the more harmony and perfection we find; what is seeming confusion in the ignorance of to-day, is order in the knowledge of to-morrow. If any one ignorant of the law which regulates the diffusion of gases were told that a heavier gas would ascend contrary to its specific gravity through the septum in a vessel containing a lighter gas above the heavier, he would naturally doubt your assertion, and say, "that is contrary to the law of gravity;" but explain to him the principle by which this comes about, and the objects of the law; the order and beauty of the design become manifest. But this is no equivocation, it is evidence there, that subordinate laws exist and nothing more. It has never been found that men have gathered "grapes of thorns and figs of thistles," nor has it ever been discovered that inanimate matter multiplies itself. The seed of disease "is within itself," multiplying and propagating itself; whether it formed a part of creation at the beginning or not, is rather a question to be solved by divines than physicians. When we know, however, the latency of seeds and even of entire plants, and that they may be dried and remain so for years yet being brought again into conditions adapted to their active existence, they, as it were, revive from their sleep, and renew again their reproductive properties: can we wonder if, in the great scheme of nature, existences new to mankind should make their appearance? When the New Zealander saw the surface of his ground producing to him unknown plants, and the skins of his children generating peculiar eruptions, and each propagating its kind, would he look, think you, to the wood or the stones, the air or the water—for the solution of the mystery? No, he would naturally say these people brought the seeds with them. From the property of reproduction possessed by these forms of matter, we infer the value of the proposition.