PREVALENCE OF ALCOHOLIC FERMENTATION 85 



in a word, they respired. But if placed in an atmosphere of limited 

 oxygen supply, they quickly absorb this and continue to liberate car- 

 bon dioxide. Lechartier and Bellamy (1869) established the formation 

 of alcohol under these conditions. This phenomenon remained un- 

 explained until Pasteur undertook his experiments, when it was 

 definitely proven to be an alcoholic fermentation. Pasteur placed 

 plums under a flask filled with CO 2 and secured 6 grams of alcohol 

 after 8 days. This same experiment was repeated on other tissues 

 containing sugar. Muntz has been able to form alcohol by placing 

 some of the higher fungi in a sugar solution. Maze, Goldewsky and 

 Polszeniuz, and a few other authors, have secured similar results 

 with certain plants. Green peas have the property, when placed under 

 water away from air, of causing a sugar solution to ferment by simple 

 contact, and act exactly as the yeasts except with less activity. 



It seems, then, as if all cells which contain sugar are able, in 

 the absence of oxygen, to function as yeast cells and produce alco- 

 holic fermentation. We shall see that the yeasts, themselves, during 

 inanition are able to produce a fermentation of their reserve glycogen, 

 thus causing a sort of autofermentation. 



" The alcoholic fermentation is not a characteristic inherent alone 

 in the yeast cell nor a necessary manifestation for its existence. It 

 is a characteristic variable with the conditions, but rather general. 

 The yeasts differ from other plants only in the characteristic that 

 they are able to adapt themselves better to anaerobic life and thus 

 show this new phenomenon which is of so much industrial impor- 

 tance." 



Differences in the Fermenting Function in Different Yeasts 



If alcoholic fermentation is not a function special to the yeasts, 

 one must not regard it as a specific characteristic. Many of the 

 yeasts are not able to produce alcoholic fermentation but act only 

 as oxidizing agents, as aerobes. Such are all of the Mycoderma and 

 even the true yeasts producing endospores, as Pichia hyalospora. 

 These form a luxuriant veil at the beginning of their development on 

 carbohydrate media, which covers the surface of the liquid; they live 

 then in contact with oxygen, consuming this gas and liberating carbon 

 dioxide. Many of the Torula, although vegetating at the bottom of 

 liquids, are also in the same class. Some of the other yeasts act like 

 molds which we have just discussed. They live by preference in con- 

 tact with air and possess only mediocre fermenting capacity. For 

 example, the Willia and Pichia and the myco-yeast of Duclaux are 

 such. 



This yeast develops on liquid media with a typical veil or scum 



