CHAPTER IT. 
COMPOSITION OF MILK. 
THE constituents of milk are numerous and of 
diverse character, but may be easily classified into a 
few well marked groups as follows: (a) water, (b) 
fats, (c) substances containing nitrogen (albumi- 
noids), (d) sugar, (e) ash. Excepting the water, they 
are collectively known as milk solids. The solids 
exist partly in solution, partly in semi-solution, and 
partly in suspension in the water. Milk from the 
various classes of animals has the same _ general 
constitution and properties, and varies only in the 
relative proportions of the various proximate ‘con- 
stituents. Cow’s milk is typical of all milks, and as 
it is the only milk used in processes of manufac- 
ture in the United States, all of our discussions 
have reference to it alone. In various other coun- 
tries milk from the goat, ass, mare and ewe is con- 
siderably used, not only as food but for the man- 
ufacture of various products. Indeed the peculiar- 
ities of some of these is supposed to be largely due 
to their having been made from the milk of ani- 
mals other than the cow. Koumiss, made from 
mare’s milk in Arabia, and Roquefort cheese, made 
largely from ewe’s milk, are noteworthy examples. 
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