BUTTER. 63 



of proteids by the Ritthausen method, the liquid made 

 up to 200 c. c., mixed, filtered through a dry filter and 

 the reducing power of 100 c. c. of the filtrate deter- 

 mined by Soxhlet's method as described. 



BUTTER. 



Butter, commercially, consists of a variable mixture 

 of fat, water and curd, obtained by churning cream 

 from cow's milk. The water contains in solution milk 

 sugar and the salts of the milk. Common salt is 

 usually present, being added after the churning. Arti- 

 ficial coloring is frequently used. 



The composition of commercial butter usually varies 

 within the following limits: 



Fat .... 78 per cent, to 94 per cent. 



Curd .... i " " " 3 " '< 



Water ... 5 " " " 14 " 



Salt .... o " " " 7 " 



Nostrums for butter making. Preparations pur- 

 porting to have the power to increase the yield of 

 butter from a given weight .of milk are now sold. 

 One of these, advertised under the name " black pep- 

 sin," has been found to contain salt , annatto and a small 

 amount of rennet. Pepsin has also been used. These 

 curdle the milk and allow the incorporation of much 

 cheese and water with the butter. It has been found 

 that butter may also, without the addition of any chem- 

 icals, be incorporated with a large amount of cream. 



