Then as to reproduction of matter by any chemical process, our author can furnish us with no examples, for even in his explanation of the causes of disease he is quite silent on this point, merely acknowledging that diseased products must be either rendered "harmless, destroyed, or expelled from the body." He further says, that "in all diseases where the formation of contagious matter and of exanthemata is accompanied by fever, two diseased conditions simultaneously exist, and two processes are simultaneously completed," and that it is by means of the blood as a carrier of oxygen that neutralization or equilibrium is established. Liebig thus admits that an agent exists in the blood, capable of deteriorating it at the expense of the oxygen, which he maintains is contained in the red globules; he further acknowledges that two processes of diseased
action are going on at the same time, and though he does not explain them, I imagine him to mean that new contagious matter is generated and eliminated from the blood, and that at the same time, there is that condition of body which he would call simply a diseased state, and characterizes it thus: "Disease occurs when the sum of vital force which tends to neutralize all causes of disturbance, (in other words, when the resistance offered by the vital force) is weaker than the acting cause of the disturbance."
If I rightly apprehend his notions, they perfectly harmonize with my ideas, to a certain extent, on the subject. They accord, at any rate, most completely with the theory attempted to be established, and fully confirm the reasonableness of the application of the facts recorded to the inference drawn from other sources. The difference only rests on the question whether vitalized or non-vitalized matter is the fons et origo mali.
How is the production of new matter, resembling that originally causing the disease, to be explained by any known hypothesis, except on the assumption of living organized matter? Though Liebig and Mulder both deny the fact, that the Torula cerevisiæ is the sole agent in the process of fermentation: they both equally fail in shewing upon what it does depend, and their difficulty rests entirely on their incapacity to explain the uniform reproductive properties of the matter engaged in this, as well as in all other allied operations. Liebig's statement
however on this matter requires notice—he says, "that putrifying blood, white of egg, flesh and cheese, produce the same effects in a solution of sugar, as yeast or ferment. The explanation is simply this; that ferment or yeast is nothing but vegetable fibrine, albumen or caseine, in a state of decomposition."
This state of decomposition, however, involves a much more complex proceeding, than simply a reduction of matter into its elementary forms of gases, earths, and minerals; for we nowhere find decomposition of this kind going on without the development of some organized bodies, either animal or vegetable: and since we have seen that the spores of the cryptogami are always in existence in the atmosphere, and making their appearance under favouring conditions, and especially when we find that fermentation is invariably accompanied, and I may safely say, preceded by the deposition in the fluid of the sporules of the Torula, we can hardly believe that they are any other than the sole agents of the process. I have now a considerable quantity of the Torula obtained from the urine of a diabetic patient, in which they appeared, as it were, spontaneously. After the urine had been allowed access to the air for a certain time, and the whole of the saccharine matter was converted into new compounds, reproduction of the Torula ceased;—and those which remained when the process was completed, still continue as organic cells, deposited
in the bottle in an inert state, but ready, on the addition of fresh sugar, as has been proved, to resume an active existence. These germs, it is now well known, may be dried into powder, so as to be blown away like dust without any, or but little, detriment to their vital energies; and there is now no doubt that they exist in this condition in the air, as do the spores of mucor, aspergillus, oidium, agaricus, and all other fungi.
Mulder, however, does allow some properties to the yeast vesicle; he says, "a variety of strange ideas have been entertained respecting the nature of yeast; recent experiments have convinced me that it undoubtedly is a cellular plant consisting of isolated cells. They resemble the composition of cellulose in some respects, but differ from it in many." "These vesicles, consisting of a substance resembling that of cells, do not contribute in the least to the fermentation, but are exosmotically penetrated during fermentation by the protein compound." These chemists seem to have an instinctive horror of allowing any active properties to the yeast vesicle, that is as far as the conversion of sugar into carbonic acid and alcohol is concerned in the act of fermentation. Dr. Carpenter, as if desiring to conciliate the chemical and physiological disputants, considers that the truth is to be found in the mean of the two extremes,—that is, that the process of fermentation is neither entirely dependent on chemical laws, nor on those laws which preside
over the growth of reproductive matter, but is a process in which both perform certain offices, each depending on the other to produce the combined result; he thus approaches more nearly to the theory of Mulder, than that of Liebig.
But to revert to Mulder, he speaks of the Torula cells being "exosmotically penetrated during the process of fermentation by the protein compound." Now the Torula is acknowledged to be one of the Fungals, and the chemical constituents of the Fungi approach very nearly that of animal tissues. They contain a peculiar principle, residing in and obtainable from them, termed Fungin, which is as highly azotised as animal fibre. The protein compound alluded to, Mulder says, is not gluten, because insoluble in boiling alcohol, and not albumen, because it is very readily dissolved in acetic acid, and he regards it as a superoxide of protein. This superoxide of protein can only have been produced by a vital action in the cells of the Torula, and as the fungi consume oxygen, and give out carbonic acid, we clearly have all the elementary conditions for their growth in almost all decomposing animal and vegetable matters. It is the nature of the fungi to live on organized matter, but always when it has a tendency to decay; it is for this reason they have been called "Scavengers." Again, we can understand why some animalized or nitrogenous matter should be necessary for fermentation, otherwise fungi could not grow, nitrogen being an essential constituent of