There is no question but that in general the development and physical well being of the young child is most fully insured when its food is mother's milk. Sometimes, however, the necessities of the case require a resort to some other food. Under such circumstances use may be made of the milk of some other mammal, such as the cow or the goat, or one of the so-called infant foods prepared wholly or in part from one or more of the cereal grains may be fed, but as will be seen, these artificial preparations should be avoided with children in the nursing period, whenever possible.

Table XLIX. Comparison Of Cow's And Mother's Milk

TABLE XLIX

Comparison of Cow's and Mother's Milk

Average Cow's Milk

Average Mother's Milk

Per Cent

PerCent

Total solids

12.90

11.80

Ash . . .......

0.70

0.20

Proteins

3.20

1.54

Sugar

5.10

6.61

Fat..........

3.90

3.45

Because the ash constituents are important as constructive material, there is also good reason for comparing the two kinds of milk on this basis.

In 100 Parts Milk Dry Substance

Cow's Milk

Human Milk

Per Cent

Per Cent

Potassium

1.67

0.58

Sodium oxid

1.05

0.17

Calcium oxid

1.54

0.24

Magnesium oxid

0.20

0.05

Iron oxid

0.003

0.004

Phosphorus oxid

1.86

0.35

Chlorine

1.60

0.32

100 Parts Milk Contains in Grains

Cow's Milk

Human Milk

Per Cent

Per Cent

Potassium oxid

0.1776

0.0795

Sodium oxid

0.6972

0.0253

Calcium oxid

0.1671

0.0489

Magnesium oxid

0.0231

0.0065

Iron oxid

0.0021

0.0008

Phosphorus oxid

0.1911

0.0585

Chlorine........

0.1368

0.0486

267. Unlike Composition Of Human And Cow's Milk

Experience has demonstrated that if cow's milk is to be fed successfully to infants it should be modified or "humanized." In order to understand why and how this is done, it is necessary to consider the chemical and physical differences between mother's milk and cow's milk. The chemical differences are well illustrated when we place side by side the average composition of the two kinds of milk. The preceding figures show that while cow's milk and mother's milk are in general alike in the kind of compounds they contain, they show marked differences in their percentage composition. The cow's milk is richer in solids, that is, has less water; and these solids are made up in much larger proportion of ash and protein than is the case with mother's milk, while in the solids of the latter the proportion of sugar is greater. The ash compounds, while alike in kind, are not far from three times as abundant in the cow's milk as in the mother's. These comparisons are based on the average composition of the two kinds of milk. The differences named are still greater when the cow's milk is from one of the butter-making breeds such as the Jersey or Guernsey, for in this case the percentage of solids may be over 15 per cent or even 16 per cent, and the protein between 4 and 5 per cent, especially if the cows are fairly well advanced in the period of lactation.