should we not have discovered the cause of this important phenomenon? The real causes of phenomena escape us. In sound philosophy the word cause should be reserved for the divine impulse which formed the universe. We can detect only correlations. One phenomenon succeeds another, and cannot exist without its manifestation; by abuse of language we then say there is relation of cause and effect.
Well, it is so. This phenomenon is general. Yes, when there is life without air, there is fermentation, and when there is fermentation there is life without air.
We all know that fruits detached from the tree and exposed to the air live, if we may so express it, like animals and certain inferior plants, for they absorb the free oxygen which surrounds them, and exhale a volume of carbonic-acid gas about equal to that of the oxygen which is introduced into their cells to produce in them certain manifestations of life, for the fruit continues to ripen. That being admitted, let us place a fruit, not in the air, but in carbonic-acid gas. Of two things, one, life, or, if you prefer, a certain chemical process, will go on in the cells of the fruit, or all chemical change will be absolutely suspended. If the latter hypothesis should be realized the fruit would remain inert, intact, and we should there have an admirable means for the preservation of fruit. But this is not the case: experiment proves that it is the first hypothesis which is realized; the simplest observation shows that fruit plunged into an atmosphere of carbonic-acid gas is modified more or less profoundly. Plums, for example, become hard and woody, and the grape takes exactly the flavor of the vintage. Where, then, have the cells of the fruit, in order to accomplish this chemical work, which, like all other work, requires the consumption of heat—where, I repeat, have they found the heat needed for these modifications, for this sort of life continued under abnormal conditions? Certainly it does not come from combustion, due to free oxygen, as when the fruit is suspended in ordinary air, for in this atmosphere of carbonic-acid gas there is no free oxygen. This heat, indispensable to the phenomena which observation detects, is furnished by the decomposition of sugar. The position is the same as in the case of the decomposition of sugar in the presence of yeast-cells living without air. This decomposition of the sugar is manifested in the fruit by the production of alcohol and of carbonic acid. Here the ferment is the cell of the parenchyma of the fruit. There is in this cell a life kept up, or a chemical process accomplished, without air; according to our theory, fermentation should be present there, and experiment shows that it is. The theory, then, receives from this fact an extension and a generalization which increase and strengthen it.
That is why in my last communication to the Académie des Sciences I expressed myself thus: "Every being, every organ, every cell which has the faculty of accomplishing a chemical process with-
