20 



Nontannin determinations must be made by shaking 200 cc of solution with a proportion 

 of wet chromed hide powder containing 70 to 75 per cent moisture, according to the follow- 

 ing table: 



100 cc must be evaporated in each case, the method of evaporation and drying pur- 

 sued to be the same as for extract analysis. 



Under "III Moisture" (Bui. 46) or "IX. Method of drying," Cir. 8 

 Revised, insert "4. For 16 hours in the combined evaporator and 

 dryer." 



[Motion to provisionally adopt the form of apparatus known as the 

 combined evaporator and drier.] 



SEPARATION OF NITROGENOUS BODIES. 



MLLK AND CHEESE PROTELDS. 



Nineteenth Convention, 1902, Bui. 73. 



[Note by the Editor. Attention is called to the methods for the 

 separation of nitrogenous bodies in milk and cheese, recommended for 

 adoption as provisional by the referee, Mr. L. L. Van Slyke, in 1902. 

 (Bui. 73, pp. 87-98.) These methods were referred to Committee B 

 shortly before adjournment, and no action has been taken on them. 

 (See also page 176 of Bui. 73.)] 



Twentieth Convention, 1903, Bui. 81, Cir. 13. 



The following method for the separation and determination of 

 casein monolactate and casein dilactate was adopted as a provisional 

 method : 



Casein monolactate and casein dilactate. 



1. Determination of casein monolactate in milk. Casein monolactate in milk coagulates 

 readily at 40 C. Hence in a milk containing only casein and casein monolactate the mono- 

 lactate can be separated by heating the milk to about 40 C., filtering the precipitate formed, 

 washing, and determining the nitrogen in the precipitate. Ten grams of milk diluted with 

 90 cc of water give good results. 



2. Separation of casein monolactate and casein dilactate. Casein dilactate coagulates 

 completely at 40 C. and below. In milk containing casein monolactate and dilactate, heat 

 10 grams of milk diluted with 90 cc of water to 40 C., and these two salts precipitate and 

 are separated from the milk casein by filtration. The washed preciptate is then treated 

 with 100 cc of a 5 per cent solution of sodium chlorid, and the whole heated to 55 C., with 

 frequent agitation for two hours. The process is facilitated somewhat by the presence of 

 pure quartz sand. The casein monolactate goes into solution and is separated from the 

 casein dilactate by filtration and washing. 



