CHAPTEE V 



The Changes which Milk undergoes 



THE number of changes which are constantly going 

 on in milk are borne witness to by the rapidity with 

 which that valuable food sours, coagulates, changes 

 its colour, etc., when kept for any time. These 

 changes are, many of them, of a very complicated 

 nature, and as yet little understood. Although not 

 always apparent, they start from the moment the 

 milk leaves the udder. Most of them are connected 

 with the action of the ubiquitous micro-organic life, 

 which is being shown more and more every year to 

 be of the highest importance in many operations. 

 In milk, of all fluids, they find their most congenial 

 home and an abundance of food, and they are not 

 long in establishing themselves in such congenial 

 surroundings. Some limit their attention to one 

 milk constituent, and some to another, so that in a 

 very short time a slow transformation of these 

 different constituents is begun, which eventually 



