Page:Popular Science Monthly Volume 7.djvu/730

710 substance of two papers read by M. Pasteur, which have been condensed in the translation only so much as was rendered necessary by the limited space which could be given them.

At the last meeting of the Academy, M. Bouillaud asked me the following question: "What are the ferments of the ferments?"

Before entering into the details required by the answer to this question, it is indispensable that I recall the results communicated by me to the Académie des Sciences a week ago, for it is a question of life under circumstances hitherto ignored. The gist of the communication to which I refer lies in this proposition—the expression of rigorously-conducted experiments—that there are circumstances under which life may appear and be kept up without the presence of air, and consequently with the entire absence of free oxygen.

Here is a 3-litre flask containing 75 grammes of pure lactate of lime, about half a gramme of the phosphate of ammonia, about 0.4 gramme of the phosphate of potash, 0.3 of the chloride of magnesium, 0.2 of the sulphate of ammonia, and a very small quantity of the sulphate of soda. We may substitute advantageously for all, except the lactate, a salt of ammonia and the ashes of an inferior organism, brewer's yeast, for example.

We boil the liquid contained in the flask, while the extremity of this curved tube, which is so placed that it will collect all the gases that may be liberated, is plunged below the surface of another portion of the same liquid contained in another vessel, which is also boiled at



the same time. The object of this operation is to deprive the contents of the flask entirely of air. We then let it cool and carry the curved end of the tube into a vessel filled with mercury.

This liquid thus arranged would remain inert forever, either protected from contact with the air, as it now is, or in contact with it, provided the air were entirely free from organic dust. Nevertheless it is suitable for the nourishment of certain beings, notwithstanding its purely mineral composition. But life is absent and would