ty
ounces of gravity and skimmed milk are required to furnish the desired
percentages of fat and protein. These twenty ounces in a
thirty-two-ounce mixture must add 20/32 or 4.50% of sugar to the
mixture. Twenty thirty-seconds of 4-1/2 or 20/32 of 9/2 = 180/64, or
practically 3% of milk sugar. It is, however, desired to have 6% of
milk sugar in the mixture. That is, 3% more of milk sugar is required.
This additional sugar must be added in the form of dry milk sugar.
Three per cent of thirty-two ounces is 3/100 of thirty-two. This will
give the amount of sugar desired in ounces. The sugar is to be
measured in rounded tablespoonfuls, or half ounces. If the figures
given above are multiplied by two, the result will be the number of
rounded tablespoonfuls needed. That is, 3/100 of 32 x 2 = 192/100
rounded tablespoonfuls, or for all practical purposes, two rounded
tablespoonfuls.

It is also desired to have the amount of lime water in the mixture
equal to 25% of the cream and milk in the mixture. There are twenty
ounces of cream and milk in the mixture. Twenty-five per cent of
twenty ounces is five ounces. Five ounces of lime water must therefore
be added. The total quantity of the mixture is to be thirty-two
ounces. The milk sugar goes into solution and, therefore, does not add
to this quantity. The difference between thirty-two and twenty-five
ounces is seven ounces. Seven ounces of water must, therefore, be
added to make up the quantity desired.

~Changing the Formula.~--It is often found necessary to change the
formula when using artificial feeding for infants, and under these
circumstances it is necessary to know the percentages of the food
constituents contained in the formula already in use. For this purpose
the following method, quoted from "Diseases of Nutrition and Infant
Feeding,"[75] is included:

~Morse and Talbot's Method.~--Suppose that a baby is taking a food
made up of--

Gravity cream 12 ounces
Skimmed milk 18 ounces
Limewater 6 ounces
Barley water 12 ounces
Milk sugar 4 rounded tablespoonfuls

"The barley water is made with two teaspoonfuls of barley flour in a
pint of water. The total quantity of the mixture is 48 ounces. Gravity
cream contains 16% fat. Twelve ounces of gravity cream in a 48-ounce
mixture will give, therefore, 12/48 of 16% of fat, or 4% fat. Both
gravity cream and skimmed milk contain 3.20% protein. There are 30
ounces of gravity cream an