212 STUDIES ON FERMENTATION. 



minutest particle of sugar is left undecomposed. This is true, 

 at least, in the case of saccharomyces pastoriaiius, but there are 

 other ferments which in such media are checked in their multi- 

 plication and in their continued action on sugar. One condition 

 indispensable to the accomplishment of fermentation in such a 

 sweetened mineral medium, by means of saccharomyces padori- 

 anus, is the absolute purity of the materials and of the ferment. 

 It is necessary that the life and physiological action of the latter 

 should be in no way interfered with by the presence of other 

 microscopic organisms. We shall have occasion to revert to 

 this important detail in connection with our growths. 



Fig. 49 represents the ferment as it appeared when examined 

 on August 11th, 1873. We can no longer recognize in it any 



Fig. 49. 



saccharomyces pastoriamis. The general appearance is spherical, 

 and there are a number of clusters of budding cells which 

 remind one at first sight of the mode of germination of brewers' 

 *' high " yeast. At a, a, a, we see globules from which 

 irregular abortive filaments have sprung, a proof of difficult 

 germination. No such monstrosities could ever have occurred 

 if we had used beer- wort or must as our nutritive medium. 



On November 25th we made another examination and sketch 

 of the ferment, the appearance of which did not difier materially 

 from that given above. The general appearance was the same, 

 consisting mostly of globules joined together in clusters of two 

 or three or more. No separation, such as occurs in the case of 



