PROPERTIES OF MILK 9 
Maximum. Minimum. 
Water aidcscaeiconsa es 90.69 80.32 
Bat vrctcumseewes eae i, 6.47 1.67 
Waseiny-znentescn tert cette 4.23 1.79 
JAIDUME DY: seccavedssnacte aces 1.44 .25 
Sugar! .uisunwedewctaaeate 6.03 2.11 
ASH Svsacckmacss sone eee 1.21 35 
These figures represent quite accurately the maximum 
and minimum composition of milk except that the maxi- 
mum for fat is too low. The author has known cows 
to yield milk testing 7.6% fat, and records show tests 
even higher than this. 
BUTTER FAT. 
This is the most valuable as well as the most variable 
constituent of milk. It constitutes about 83% of butter 
and is an indispensable constituent of the many kinds of 
whole milk cheese now found upon the market. It also 
measures the commercial value of milk and cream, and 
is used as an index of the value of milk for butter and 
cheese production. 
Physical Properties. Butter fat is suspended in milk 
in the form of extremely small globules numbering about 
100,000,000 per drop of milk. These globules vary con- 
siderably in size in any given sample, some being five 
times as large as others. The size of the globules is 
affected mostly by the period of lactation. As a rule the 
size decreases and the number increases with the advance 
of the period. In strippers’ milk the globules are some- 
times so small as to render an efficient separation of the 
cream and the churning of same impossible. 
The size of the fat globules also varies with different 
breeds. In the Jersey breed the diameter of the globule 
