657 
First. That as mother’s milk is an ideal food, supplying the infant 
with proteid, fat, and carbohydrate in proportions adapted to its 
needs, the only logical substitute is a food that will do the same. 
Second. The substitute should approximate mother’s milk (a) in 
the energy quotient that it furnishes, (b) in proximate principles, 
and ( c ) in the amounts necessary to produce these results. 
Third. These conditions are secured only by some animal milk. 
While infants have been successfully fed on the milk of other do- 
mestic animals, such as the goat, the horse, and the ass, cow’s milk is 
the only substitute commercially and practically available in this 
country as a food for the artificial feeding of infants less than 1 year 
of age. 
C omparison of colons milk and woman's milk . — In order to proceed 
with intelligence it is necessary to compare the average composition 
of woman’s milk with cow’s milk. The following table shows the 
difference between their average composition: 
Woman's 
milk. 
Cow’s 
milk. 
Fat 
Per cent.a 
4.00 
1.50 
7.00 
.20 
87.30 
Per cent.a 
a 00 
4.50 
4.50 
.75 
87.25 
Proteid _ . _ 
Sugar 
Salts 
Water 
Calories per kilo 
100.00 
710. 50 
100.00 
700. 00 
a Average. 
Cow’s milk is more opaque than woman’s milk, although woman’s 
milk may contain a greater percentage of fat. This is due to the 
greater content of calcium salts in cow’s milk bv reason of its 
greater proportion of casein. 
In reaction cow's milk, though slightly alkaline or amphoteric 
when freshly drawn, soon becomes somewhat acid, while woman’s 
milk is amphoteric or alkaline. 
As there is very little difference in total solids between the two, 
their specific gravity is about the same. 
The sugar of cow’s milk and woman’s milk is lactose in complete 
solution. They differ, however, in quantity, as woman’s milk con- 
tains 6 to 7 per cent, while cow’s milk has usually 4.5 per cent. The 
greater part of the fat in cow’s milk is neutral fat, as in woman’s 
milk: but cow’s milk contains far greater quantities of the volatile 
fatty acids, of which there are but traces in woman’s milk. It is 
in the proteids that the chief difference between cow’s milk and 
woman’s milk is manifest. Cow’s milk has on the average 3.50 per 
24907— Bull. 41—08 42 
