GENERAL CHEMISTRY OF MILK 



Milk is composed of simple and complex substances which are 

 so balanced as to meet the requirements of young mammak. 

 The milk of different species of mammals varies greatly in com- 

 position, as shown in the following table (compiled from various 

 sources) : 



COMPOSITION OF THE MILK OF DIFFERENT MAMMALS 



Specific 

 Animal. gravity. 



Man 1.0298 



Cow 1.0313 



Cow colostrum ... 1 . 042 



Ara 1.032 



Sheep 1.0355 



Goat 1.0305 



Mare 1.0347 



Reindeer 



Rabbit 1.047 



Dolphin 



Sow 1.038 



Bitch 1.035 



Elephant 1.0313 



Camel 1.042 



Llama 1.034 



Buffalo 1.035 



There are distinct groups of compounds which are contained 

 in all milks, although in different proportion. These groups are: 



1. Fat. 



2. Proteins. 



3. Carbohydrate. 



4. Salts. 



5. Water. 



In addition, there are other substances present in small 

 amounts, namely: lecithin, nitrogen-containing extractives, cho- 

 lesterin, lactosen (a carbohydrate), orotic acid, a pigment, citric 

 acid, a mucin (lactomucin), gases, and besides these chemical 

 compounds, enzyms, and antibodies. The milk enzyms are either 

 products of the milk glands or of bacteria which are always pres- 

 ent in the udder. The antibodies are transmitted from the 

 maternal system to the young through milk. 



Some chemical compounds have frequently been isolated from 

 milk, such as amino-acids, ammonia, hydrogen sulphid, marsh- 

 gas, and others, but it is doubtful whether these are normal con- 

 stituents of milk, or whether they are formed by microbial action 



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