18 MILK HYGIENE 



ference in different kinds of milk. The latest investiga- 

 tions concerning the powers of the living animal to 

 form specific anti- albumins (precipitins) following the 

 injection of albumin solutions, prove, however, that the 

 casein of different species of animals has certain dif- 

 ferences, even though these are so slight that they can- 

 not be detected chemically. 



The lactalbumin is very similar to the albumin of the 

 blood, but it appears to differ from this in some particu- 

 lars. It coagulates at about 70 C., and, like all other 

 albumins, it is not precipitated in a neutral solution 

 of sodium chloride and magnesium sulphate, but it is 

 precipitated in a saturated solution of ammonium 

 sulphate. 



The lactoglobulin occurs in milk in very small quan- 

 tity, merely in traces, while colostrum is comparatively 

 rich in this substance. It coagulates at 75 C. ; it is pre- 

 cipitated in the same way as serum globulin and, like 

 serum globulin, is insoluble in water, but is soluble to 

 some extent in weak salt solution. 



Carbohydrates. Of the carbohydrates, lactose, or milk 

 sugar, occurs as a constant constituent in the milk of 

 the cow and of most other mammals. Some investiga- 

 tors claim that in colostrum there is a monohexose, 

 which is probably glucose, and it is not unlikely that in 

 the milk of certain animals other kinds of sugar appear ; 

 for example, it is cited that a peculiar kind of sugar, 

 tewficose, is found in considerable quantity in the milk 

 of the Egyptian buffalo. 



Lactose (C 12 H M O ll + H 2 0) is a disaccharid which 

 is split by hydrolysis (e.g. by means of heating with 

 dilute acids, action of ferments) into glucose (grape 

 sugar) and galactose as follows : 



C 12 H M O n + H 8 = C 6 H 12 6 + C 6 H 12 6 



Lactose Glucose Gulactose 



