376 CURDLING OF MILK. [BOOK n. 



remain in solution ; if calcic phosphate be present, the one, viz. 

 the curd 1 , becomes insoluble. 



Rennin is abundant in the gastric juice and in the gastric 

 mucous membrane of ruminants, but is also found in the gastric 

 juice of other animals, and either it, or what we shall presently 

 have occasion to speak of as the antecedent of the ferment or 

 zymogen is present also in the mucous membrane of the stomach 

 of most animals. A very similar if not identical ferment has also 

 been found in many plants. 



1 It might be useful, in order to distinguish the curd from the natural soluble 

 casein, to call the former tyrein (rvpbs, cheese), and so reserve the name of casein 

 for the latter. 



