STUDIES ON FERMENTATION. 175 



tion in yeast-water, in contact with pure air. Strange to say, 

 it has lost its elongated appearance, and would appear to 

 have originated from a round ferment. The cells are much 

 exhausted, and most of them seem to have a double border ; 

 their interior is very granular and of a yellowish colour. 

 One might readily take the specimen to be a dead old 

 ferment, which, however, it by no means is. 



Fig. 36 represents the germination of this ferment, which 

 had previously been revived in a flask of wort, at the tempera- 

 ture of the air, in May, 1875. The following are the details of 

 our observation : — 



We sowed a trace of the exhausted yeast (Fig. 35) in a 

 flask of wort on May 16th. The sketch (Fig. 36) was made 

 on May 19th, but on the 18th there was a sensible revival. It 

 will be seen how much the little ferment had developed in 

 the course of three days from the time when the process com- 

 menced. If we had waited a few days longer before taking 

 our sample, we should probably have had difiiculty in finding 

 any cells or filaments of the large ferment form, as there would 

 have been so few of them in comparison with the others. 



Co 



Fig. 36. 



In the above figure we should remark the chain of large 

 cells and long-jointed processes, a, h, c, d : d is one of the cells 

 that we sowed ; it has become transparent, and its contents, 

 which are slightly granular, have lost their brownish tint ; c is 

 a large cell which sprang from the preceding one ; its outline 



