A DAIRY LABORATORY GUIDE 79 



EXERCISE XVII 



USE OF RENNET. PRECIPITATION OF 

 ALBUMEN 



Take i8 grams of milk in a white cup and cool to 

 50° F. Add four drops of rennet and note 

 time it takes the milk to coagulate. Com- 

 pare this with the same amount of milk 

 warmed to 85° F., to which four drops of 

 rennet have been added. 

 . Boil some whey and note the albumen which is 

 thrown down in a white flocculent pre- 

 cipitate. Fill your lightning top sample jar 

 about one-half full of skimmed milk at about 

 100° F. Add I cc. of rennet. Set aside to 

 coagulate. Then strain ofif the whey and 

 precipitate the albumen in the whey by boil- 

 ing. 



In both cases the boiling should be done in a 

 test tube. It may at first be difficult to see 

 albumen, as it is in very fine particles. The 

 albumen may be distinguished more readily 

 by holding the test tube between the eye and 

 the window. 



Turn in desk, key and locker. See that all glass- 

 ware is clean before turning in the desk. 



