Kkw York Agriccltdral Experiment Station. I'i3 



there is added about one gram of common salt, together with an 

 excess of ten per ct. tannic acid solution. The precipitate 

 formed is filtered and washed and the nitrogen determined in an 

 aliquot part of the filtrate. From this amount of nitrogen is 

 deducted the amount of nitrogen found as ammonia in (g) and 

 the remainder is the amount of amide nitrogen. 



(g) Ammonia. — To an aliquot portion of the filtrate obtained 

 in (f), magnesium oxide is e.dded and the ammonia separated bj 

 distillation. 



DETERMINATION OP NITROGEN-COMPOUNDS IN MILK. 



Casein.— To 20 gms. of milk, diluted with water to about 

 100 cc, are added 2 to 2J cc. of saturated alum solution. The 

 determination is completed as under (b) in cheese extract, and 

 the other determinations are made as described above in the 

 cheese extract. 



DETERMINATION OF CHLOROFORM IN CHEESE AND MiLK. 



About 5 gms. of milk or cheese are placed in a pressure bottle 

 with about 10 cc. of alcohol and 5 gms. caustic potash. The 

 bottle and contents are then heated 30 minutes at 230° F. 

 (110° C.) in an autoclave. The resulting chloride is determined 

 volumetrically as in case of chlorine in sodium chloride. 



FORM OF STATING RESULTS. 



The figures given in the various tables represent percentages 

 of the total nitrogen in milk and cheese. This form of state- 

 ment is usually preferable, as figures representing the actual 

 percentages in milk and cheese are often very small. Hence, 

 considerable variations, expressed in percentages of nitrogen, 

 often represent very small variations when expressed in actual 

 amounts present in cheese and milk. 



The soluble nitrogen in milk, as used in this bulletin, includes 

 all nitrogen compounds except casein and albumin. The water- 

 soluble nitrogen in cheese includes all the nitrogen soluble under 

 the conditions indicated in preparing the water extract of 

 cheese. 



