148 SCIENCE AND PRACTICE OF CHEESE-MAKING 



are due, apparently, to the formation of ^this brine- 

 soluble substance. More or less of this peculiar 

 substance remains in the cheese indefinitely. For 

 example, in a cheese two-and-one-half years old, 

 the portion of the cheese insoluble in ether (fat) 

 and in warm water consisted entirely of this brine- 

 soluble substance. On being warmed, it could be 

 drawn out in strings over a yard long. (Figs. 32 

 and 33.) 



FIG. 32 BRINE-S L U B L E FIG. 33 STRINGS OF BRINE- 



CHEESE PROTEIN WARMED 

 AND FRESHLY DRAWN 

 OUT IN A STRING SEV- 

 ERAL FEET LONG 



SOLUBLE PROTEIN OF 



CHEESE SUSPENDED AND 



DRIED. STRINGS ABOUT 



FOUR FEET LONG 



MILK-SUGAR 



Milk-sugar, also called lactose, is present in cow's 

 milk in solution. In general composition, it re- 

 sembles ordinary sugar, but it is less sweet and 

 less soluble in water ; however, it differs much from 



