STUDIES ON FERMENTATION. 79 



"We may safely conclude that our torula, in the course of its 

 development in must, with a weight that would have been 

 very appreciable, did not produce, by its action of multiplica- 

 tion io-{«o of 1 c.c. of alcohol. 



Under the following conditions we obtained a slightly 

 different result, which, nevertheless, confirmed the preceding one. 



On July 5th, 1872, we opened and closed twelve flasks similar 

 to those we had used before, the sole difference being that they 

 contained yeast water * sweetened with ten per cent, of sugar. 

 One of these flasks furnished us similarly with one kind of 

 torula, which bore the greatest resemblance to the ferment of 

 beer. When this torida was beginning to spread all over the 

 bottom of our flask, we shook up the liquid, and turned the 

 flask upside down, with the object of submerging the torula and 

 depriving it of air, at least at the bottom of the neck. For 

 some days, and even months, there were no signs of the libera- 

 tion of gas. On July 22nd, 1873, after the interval of a year, 

 we opened the flask (which gave no indication of the existence 

 of an interior pressure) and endeavoured to discover the pres- 

 ence of alcohol, by means of successive distillations, as just 

 described. In the two first distillates there seemed to be no 

 alcohol, but in the third we detected its presence in ver}^ small 

 quantity. We shall see, later on, that the formation of such a 

 small quantity of alcohol may be attributed to the fact of the 

 plant having been submerged when in full growth, and to its 

 having continued to live for some time after its submersion quite 

 independently of the oxygen contained in the air of the flask. 



small long-necked retort and a Liebig's condenser. "We must carefully 

 watch tlie neck of the retort at the moment of boiling ; should the liquid 

 contain y^joo P^^^ ^^ ^^^ volume of alcohol, we shall observe the indica- 

 tions given above for a short, but appreciable time, -^j]^ of alcohol is 

 difficult to judge, but with care and practice we may do it without fail- 

 ing. Collecting a third of each distillate, and supposing the limit of 

 appreciation to stop at thousandths, in three distillations we may easily 

 detect the presence of lo^ooo of 1 c.c. of alcohol in a total volume of 100 c.c. 

 * Yeast when macerated in water imparts to it certain soluble nitro- 

 genous materials. The solution so obtained, filtered from yeast globules, 

 is known as yeast ivater. — D. C. R. 



