Considerably less than of the milk sugar. Usually about half the quantity (half an ounce to twenty ounces of food) is as much as most infants can digest If the same quantity is used as of the milk sugar, the food is made unduly sweet, and the sugar is likely to ferment in the stomach and cause colic.
Is not the purpose of the sugar to sweeten the food in order to make it palatable?
Not at all; although it does that, its real use is to furnish one of the essential elements needed for the growth of the body, and the one that is required by young infants in the largest quantity.
How do we know that this is so?
By the fact that in good breast milk the amount of sugar is greater than that of the fat, proteids, and salts combined.
We have seen that cow's milk has nearly three times as much proteids (curd) and salts as mother's milk. How are these to be diminished?
By diluting the milk.
Will it be sufficient to dilute the milk twice (i.e., add two parts of water to one part of milk)?
Not for a very young infant. Although this will give about the quantity of proteids present in mother's milk, the proteids of cow's milk are so much more difficult for the infant to digest, that in the beginning it should be diluted five or six times for most infants.
If cow's milk is properly diluted and lime-water and sugar added does it then resemble mother's milk?