CA′SEIN

Syn. Ca′seum , Ca′sein , Lactalbu′men , Albumen of milk . The nitrogenous principle of milk. Cheese made from skimmed milk and well pre ed is nearly pure casein. (Liebig.) Prep. 1. The curd obtained by adding dilute sulphuric acid to milk is well washed and di olved in carbonate of soda. It is allowed to stand for 24 hours, to let the oil rise to the surface, and when this is properly skimmed off, the casein is precipitated by an acid. The proce is repeated a second time, and the coagulum digested with alcohol and ether, and dried. With all these precautions the casein still contains some saline matter which cannot be removed. 2. Milk is coagulated by hydrochloric acid, and the curd then well washed with dilute acid, and finally with pure water. The curd so prepared is di olved by digestion at 110° Fahr., with a large quantity of water; the solution, after filtration, is coagulated with carbonate of ammonia; the coagulum is washed with water, ether, and alcohol, and finally dried. Prop., . Coagulated casein is readily di olved by the alkalies and alkaline carbonates. The most remarkable property of casein is its coagulation by certain animal membranes, as in the proce of cheese-making with rennet. See Lactarin .