MILK 415 
market, some of which are exccllent and skim to the 
merest trace of fat in the skim milk. The first practical 
cream separator was invented in 1879 by Dr. Gustav 
De Laval, a citizen of Sweden, who died in 1913: In the 
process of separation the milk flows into the bowl, 
and, partaking of the centrifugal force, its heavier 
portions are carried into the 
skim milk outlet at the outer 
edge, and the lighter portion into 
the cream outlet at the center. 
The cream separator has revolu- 
tionized the practice of butter 
making in this and other lands. 
On every farm where two or 
more cows are kept the sep- 
arator will prove an economical 
purchase. Other systems of 
cream raising will sooner or later 
become obsolete, because their use means a money loss. 
Dr. Gustav De LavaL 
12. Skim milk.—This milk product is a valuable food 
for man and beast, since only fat is largely removed in 
creaming. The othér constituents, casein, sugar, ash 
and water, are a right combination for pigs, calves and 
chicks. By substituting corn meal or wheat middlings 
for the butter fat removed in separation, an ideal ration 
is obtained. The best time to use skim milk is immedi- 
ately after it comes from the separator. It is then sweet 
and warm, the milk sugar is not yet destroyed by lactic 
acid germs, and the full feeding value will be secured. 
When milk is fed fresh and sweet, digestive disorders 
seldom occur. 
13. Market milk—There is no substitute for clean, 
pure milk. It is nutritious, palatable, cheap. Its con- 
