Page:Popular Science Monthly Volume 7.djvu/732

712 not come to interfere with life and health. In a moment, if you choose, I will make them ill, all these little beings.

We have not finished with the peculiarities of our experiment, which will appear the more remarkable and instructive as you study it more closely. Let us weigh the vibrios that have been formed when the process ceases, when all internal movement has disappeared, and when they have fallen inert to the bottom of the flask, because they have exhausted their principal food, the lactic acid, transforming it into butyric acid, which is absolutely unfit for their existence, you will know why in a moment when I describe fermentible materials. Let us compare this weight of the vibrios with that of the 75 grammes of the transformed lactate of lime. The difference is considerable. I cannot now give you the exact figures, but the proportion is at the most as 1 to 200. What does that mean? an agent which causes the decomposition of a weight of matter 200 times as great as itself! But that is the characteristic of the phenomena to which chemists have given the name phenomena of fermentation. Yes, we have had to do with a real fermentation, in which the lactic acid is the fermenting substance and the vibrios the ferment.

Who would dare now to maintain that fermentations are phenomena of contact, phenomena of movement communicated by an albuminoid substance which is undergoing change, or of phenomena produced by semi-organized substances which are being transformed into this or into that? All these scaffoldings built by the imagination crumble before our experiment, so simple and so demonstrative.

Still, the most essential and, so to speak, dominant circumstance in our experiment has not yet been introduced, and it is time for me to submit it to your attention.

We prepared at the beginning a nutritive liquid, deprived entirely of air and protected from contact with it; we then sowed vibrios in it, and, during the weeks that have elapsed, our liquid has never been uncovered. Nevertheless, the vibrios have multiplied infinitely. Here, then, is life—that is to say, nutrition and generation—without the slightest aid from air or free oxygen. And in this experiment two things have marched side by side, life without air and fermentation. Ah, if that was a general phenomenon; if life as we know it, with absorption of free oxygen, was not accompanied by fermentation properly so called; if the weight of assimilated food corresponded to that of food ingested and used under the influence of respiration; and if, on the other hand, life without air was always associated with fermentation; if, in the latter case, life resulted in the transformation of an enormous weight of food as compared with the weight of the nutritive assimilation—should we not have raised the veil of these mysterious phenomena of fermentation?

From the moment it should be established that there is correlation between the fact of life without air and the fact of fermentation,