108 STUDIES ON FERMENTATION. 



Firstly, That neither 2)enicilliiini nor uspergillua glaiicus can 

 change into yeast, even under conditions that are most favour- 

 able to the life of that ferment. 



Secondly, That a fungoid growth which vegetates by using 

 the oxygen of the air, and which derives from the oxidating 

 action of that gas, the heat that it requires to enable it to per- 

 form the acts necessary to its nutrition, may continue to live, 

 although with difficulty, in the absence of oxygen ; that, in such 

 a case, the forms of its mycelian or sporic vegetation undergo a 

 change, the plant, at the same time, evincing a great tendency 

 to act as alcoholic ferment, that is to say, decomposing sugar 

 and forming carbonic acid gas, alcohol, and other substances 

 which we have not determined, and which probably vary with 

 different growths. 



Such, at least, is one interpretation of the facts that we have 

 reviewed. The observations in the following paragraphs and 

 chapters may the more incline our readers to accept it as the 

 true one. 



§ II. — Growth of Mycoderma Vini in a state of Purity — 

 Confirmation of our original Conjectures as to the 

 CAUSE of Fermentation — Mycoderma Vini does not 

 Change into Yeast, although it may give rise to 

 Fermentation. 



The efflorescence of wine, cider, and beer is pretty generally 

 known.* Fermented liquors cannot be exposed to the air with- 

 out soon becoming covered with a white film, which grows thick 

 and becomes wrinkled in a marked manner in proportion as it is 

 deprived of room wherein to spread horizontally, in accord with 

 the extraordinary multiplication of the cellules that compose it. 

 The rapidity of this multiplication is sometimes astounding. 

 During the heat of summer, when the medium is well adapted 

 to the life of the plant, we maj^ count the number of cells which 

 grow in the course of a few hours by millions. The absorption 



* See Pasteub, Etudes sur h Vin, 1st Edition, pp. 20 and following. 



