A Dairy Laboratory Guide 



THE COMPOSITION OF MILK 



Milk is composed of a great many substances, 

 but, so far as the dairyman is concerned, there are 

 only six constituents which are of prime impor- 

 tance. The following table gives the constituents 

 of milk, together with the per cent of each, ob- 

 tained by a large number of analyses : 



Water 87 . o per cent 



Fat 4.0 per cent 



Casein 2. 6 per cent 



Sugar 5.0 per cent 



Albumen 0.7 per cent 



Ash 0.7 per cent 



Although in the above table the different con- 

 stituents are given definite per cents, yet the com- 

 position of normal milk is very variable. The 

 water needs no discussion, as it is just like the water 

 found anywhere else in nature. 



Fat is present in milk in the form of minute drop- 

 lets or globules. These globules are distributed 

 throughout the milk and are not in solution, but 

 in fine suspension. This state is called an emulsion. 

 It was disputed for a long time as to whether or not 

 the fat globule had a membrane around it. It is 

 now believed by the best authorities that the fat 

 globule has no membrane, but that the droplet 



