[It may be useful for the non-scientific reader to put it thus:—that the 25 c.c. which escaped, being a fair sample of the whole gas in the flask, and containing (1) 25 - 20·6 = 4·4 c.c., absorbed by potash and therefore due to carbonic acid, and (2) 20·6 - 17·3 = 3·3 c.c., absorbed by pyrogallate, and therefore due to oxygen, and the remaining 17·3 c.c. being nitrogen, the whole gas in the flask, which has a capacity of 315 c.c., will contain oxygen in the above proportion, and therefore its amount may be determined, provided we know the total gas in the flask before opening. On the other hand, we know that air normally contains, approximately, 1/5th its volume of oxygen, the rest being nitrogen, so that, by ascertaining the diminution of the proportion in the flask, we can find how many cubic centimetres have been absorbed by the yeast. The author, however, has not given all the _data_ necessary for accurate calculation.—D.C.R.] Footnote 119: This number is probably too small; it is scarcely possible that the increase of weight in the yeast, even under the exceptional conditions of the experiment described, was not to some extent at least due to oxidation apart from free oxygen, inasmuch as some of the cells were covered by others. The increased weight of the yeast is always due to the action of two distinct modes of vital energy—activity, namely, in presence and activity in absence of air. We might endeavour to shorten the duration of the experiment still further, in which case we would still more assimilate the life of the yeast to that of ordinary moulds. Footnote 120: In these experiments, in which the moulds remain for a long time in contact with a saccharine wort out of contact with oxygen—the oxygen being promptly absorbed by the vital action of the plant (see our _Mémoire sur les Générations dites Spontanées_, p. 54, note)—there is no doubt that an appreciable quantity of alcohol is formed because the plant does not immediately lose its vital activity, after the absorption of oxygen. A 300-c.c. (10-oz.) flask, containing 100 c.c. of must, after the air in it had been expelled by boiling, was opened and immediately re-closed, on August 15th, 1873. A fungoid growth—a unique one, of greenish-grey colour—developed from spontaneous impregnation, and decolorized the liquid, which originally was of a yellowish-brown. Some large crystals, sparkling like diamonds, of neutral tartrate of lime, were precipitated. About a year afterwards, long after the death of the plant, we examined this liquid. It contained 0·3 gramme (4·6 grains) of alcohol, and 0·053 gramme (0·8 grain) of vegetable matter, dried at 100° C. (212° F.). We ascertained that the spores of the fungus were dead at the moment when the flask was opened. When sown, they did not develop in the least degree. Footnote 121: