FERMENTS AND FERMENTATION. 91 



ment wall as soon as formed and are carried off by the 

 stream of water. The products cannot therefore accumulate 

 and be synthesized into fat. In this way all the fat is 

 ultimately split into fatty acid and alcohol. 



(e) For reasons which are at present not well under- 

 stood, the fermentative activity of extracts of organs or the isolated 

 ferments of the alimentary secretions is disappointingly low 

 when compared with the activity of the uninjured organ or the 

 freshly obtained secretion. The fact that all the ferments 

 thus far studied are apparently colloidal in character, and 

 consequently exceedingly sensitive to changes in their sur- 

 roundings, is perhaps responsible for this, at least in part. 

 Some very active preparations of ferments have, however, 

 been described^ The most active are, no doubt, the prepara- 

 tions of amylase prepared by WEiNLAND. 1 The following two 

 experiments, taken from his note-books, may serve as illus- 

 trations. 



(a) Forty-one grams of the mixed pancreas from three pigs 

 are ground up for ten minutes in a mortar with 41 grams of 

 quartz sand. To the mixture are added 21 grams of infusorial 

 earth, and the whole is ground for another ten minutes. A 

 paste results. This paste is placed in a cloth and subjected to 

 the pressure of a BUCHNER press. Only 7 c.c. of juice (1) are 

 obtained. On the following day the paste is mixed with 

 30 c.c. of 0.9 percent NaCl solution and 10 c.c. of disodium 

 phosphate solution. This gives a somewhat thin mixture. 

 This is again put under the press and 29 c.c. of juice are ob- 

 tained, to which are added the 7 c.c. (1) obtained before. A 

 third pressing raises the entire amount of extract to 43 c.c. 

 (in other words, about the volume of the original amount of 

 pancreas). The extract is filtered, when a clear, yellowish 

 solution results, and this is covered with toluol to prevent 

 the development of bacteria. Five days later 5 c.c. of a two- 

 percent glycogen solution (upon which amylase acts as readily 

 as upon starch) are mixed at room temperature with a little 

 KI-I solution, when the whole assumes a dark-red color, 

 indicating the presence of the glycogen. To this mixture there 



1 WEINLAND: Personally communicated. 



