Such is the large volume of oxygen necessary for the development of one gramme of yeast when the plant can assimilate this gas after the manner of an ordinary fungus.

Let us now return to the first experiment described in the paragraph on page 292 in which a flask of three litres capacity was filled with fermentable liquid, which, when caused to ferment, yielded 2.25 grammes of yeast, under circumstances where it could not obtain a greater supply of free oxygen than 16.5 cc. (about one cubic inch).  According to what we have just stated, if this 2.25 grammes (34 grains) of yeast had not been able to live without oxygen, in other words, if the original cells had been unable to multiply otherwise than by absorbing free oxygen, the amount of that gas required could not have been less than 2.25 X 4l4 cc., that is, 931.5 cc. (56.85 cubic inches).  The greater part of the 2.25 grammes, therefore, had evidently been produced as the growth of an anaerobian plant.

Ordinary fungi likewise require large quantities of oxygen for their development, as we may readily prove by cultivating any mould in a closed vessel full of air, and then taking the weight of plant formed and measuring the volume of oxygen absorbed.  To do this, we take a flask of the shape shown in Fig. 8, capable of holding about 300 cc. (10 1/2 fluid ounces), and containing a liquid adapted to the life of moulds.  We boil this liquid, and seal the drawn-out point after the steam has expelled the air wholly or in part; we then open the flask in a garden or in a room.  Should a fungus-spore enter the flask, as will invariably be the case in a certain number of flasks out of several used in the experiment, except under special circumstances, it will develop there and gradually absorb all the oxygen contained in the air of the flask.  Measuring the volume of this air, and weighing, after drying, the amount of plant formed, we find that for a certain quantity of oxygen absorbed we have a certain weight of mycelium, or of mycelium together with its organs of fructification.  In an experiment of this kind, in which the plant was weighed a year after its development, we found for 0.008 gramme (0.123 gram) of mycelium, dried at 100 degrees C. (212 degrees F.), an absorption that amounted to not less than 43 cc. (2.5 cubic inches) of oxygen at 25 degrees.  These numbers, however, must vary sensibly with the nature of the mould employed, and also with the greater or less activity of its development, because the phenomena is complicated by the presence of accessory oxidations, such as we find in the case of mycoderma vini and aceti, to which cause the large absorption of oxygen in our last experiment may doubtless be attributed. [Footnote:  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 Memoire sur les Generations dites Spontanees, p. 54. note)—­there is no doubt that an appreciable quantity of alcohol is formed because the plant does not immediately lose vital activity after the absorption of oxygen.