To the Editor of the Popular Science Monthly.
I HAVE read with no ordinary interest the lecture by Prof. Tyndall, published in your issue of December, upon the subject of "Fermentation and its Bearings upon the Phenomena of Disease;" and I desire, with your permission, to submit some points suggested to my mind upon which, according to my own conception, there remains some doubt, and which I should like to see explained. It is not my intention to dwell upon the general subject of the nature and causes of fermentation, but merely to touch upon it, confining myself rather to the question of the causes of putrefaction.
In fermentation and the production of alcohol, the presence of bacteria seems to be constant. Prof. Tyndall holds that the changes resulting in the formation of beer and the production of alcohol are due to the action of these microscopic germs, which, seizing upon the grain, or fruit, elaborate the spirit. Now, it does not seem to me perfectly clear that the changes which take place in the fruit may not be purely chemical, and that a portion of the component elements of the fruit, not requisite to form the chemical combination of alcohol, becomes a suitable soil in which the air-germs can take root and grow. It is a question of cause and effect.
Again, a certain amount of moisture is necessary to the production of mould. It may be asked: Is it quite certain that the moisture is not the agent of a chemical decomposition, and that the growth of mould is due to the deposit of seed in soil furnished by this decomposition? May it not be that a dry and cold atmosphere prevents or retards chemical decomposition in devitalized organic matter, while heat and moisture cause or facilitate it? Why should we disregard the chemical forces in the decomposition of organic matter deprived of vitality? Or, does Prof. Tyndall wish us to regard all organic matter as possessed of vitality until it is decomposed? Indeed, he says: "Cherries, apples, peaches, etc., are composed of cells, each of which is a living unit;" and "the living cells of fruit can absorb oxygen and breathe out carbonic acid, exactly like the living cells of the leaven of beer." We know that the seed of fruit possesses vitality; but is it proof of vitality in the cells, that certain changes take place between the constituents of the cells and the external air, and that other changes take place when the fruit is excluded from the air? Granting it is, then shall we say that all vegetable products, although long since uprooted but undecomposed, are possessed of life? Are the cells which compose the well-worn oak-beams of the few remaining wooden walls of Old England still endowed with vitality, and constantly engaged in a struggle for life with the low forms of animated Nature? Then, if this be conceded, might we not assume that fructification of germs is likewise essential to the decomposition of minerals? If the decay of an old boot is dependent upon the growth of mould, may we not suppose that the rusting of an old axe is due to similar influences; and that the erosion of rock, which in time forms abundant soil for vegetation, is the work of microscopic germs, although commonly supposed to be due to physical forces?
Prof. Tyndall says that "some of the numberless air-germs produce acidity, some putrefaction." But when acidity takes place rapidly, as in a frozen apple just thawed, and with an unbroken skin, are we still to regard it as the result of bacteria? With regard to putrefaction, Prof. Tyndall cites a number of experiments with beef-tea. Now, to make these perfectly satisfactory, it seems to me that the fluid ought to be exposed to not a limited quantity of pure air, but a free change of air from which all motes had been removed.
I now come to the subject of putrefaction in connection with the living body, and the antiseptic treatment of wounds as taught by Prof. Lister, of Edinburgh. Prof. Tyndall says that he has obtained "a specific against putrefaction and all its deadly consequences." This statement might lead the public to believe that the teachings of Prof. Lister were generally accepted by the medical profession. Such, however, is by no means the case, notwithstanding his practice has been thoroughly tried in most if not all the principal hospitals of Europe and America. While a certain number have adopted his method, the majority have rejected it, with the conviction that other treatment less troublesome is quite as, if not more, successful. That Prof. Lister's theories and practice are not believed in by the representative surgeons of the United States, was clearly demonstrated at the late International Medical Congress, at Philadelphia. Prof. Lister was