150 



Dairy Bacteriology. 



that is to be added to the cream, since otherwise the 

 starter cannot be uniformly mixed with it and white 

 specks of curdled casein will be noted in the butter. 



FIG. 32. AN INCUBATING CHAMBER FOR STARTERS. 

 The inner compartment will hold a pail of water and the bot- 

 tles for the mother starters. The temperature can be kept 

 at any desired point by the use of warm or cold water. The 

 four-inch space between the walls is filled with hay or min- 

 eral wool. 



The firmness of the curd is not so dependent on the 

 amount of acid formed as upon other factors. If the 

 curd shrinks to any extent and the whey is expressed, 

 it is certain to produce a starter that will contain lumps 

 that cannot be broken up. With a pure culture of lactic 

 bacteria, there is little difficulty in this regard, but as 



