126 DAIRY FARMING 



is one eight-thousandth of an inch, in the Holstein one 

 twelve-thousandth, while the average for all breeds is 

 about one ten-thousandth. 



Night's milk usually has smaller globules than morn- 

 ing's. The size of the globules also decreases with the 

 age of the cow. 



The density or specific gravity of butter fat at 100 F. 

 is .91 and is quite constant. Its melting point varies 

 between wide limits, the average being 92 F. 



Composition of Butter Fat. According to Richmond, 

 butter fat has the following composition : 



Butyrin 3.85 J 



Caprcin 3 .60 I Soluble or volatile. 



Caprylin 55 \ 



Caprin 1 . 90 



Laurin 7.40 



Myristin 20 . 20 



Palmitin 25.70 



Stearin 1 . 80 



Olein, etc 35-OO ^ 



Insoluble or 

 non-volatile. 



This shows butter fat to be composed of no less than 

 nine distinct fats, which are formed by the union of 

 glycerine with the corresponding fatty acids. Thus, buty- 

 rin is a compound of glycerine and butyric acid ; palmitin, 

 a compound of glycerine and palmitic acid, etc. The 

 most- important of these acids are palmitic, oleic, and 

 butyric. 



Palmitic acid is insoluble, melts at 144 F., and forms 

 (with stearic acid) the basis of hard fats. 



Oleic acid is insoluble, melts at 57 F., and forms the 

 basis of soft fats. 



