is a fraction whose
denominator is 100 and whose numerator is the given number of
hundredths; thus 6% of a number is 6/100 of that number.

The method of figuring the per cent. of foodstuffs in a food material
is simple. Milk, for example, has a percentage composition of 3%
protein, 4% fat, and 5% sugar. To find the definite amounts of these
foodstuffs in 1 ounce of milk it is best to reduce the ounce to grams,
since the gram is the unit of measurement generally used.

1 ounce = 28.35 grams
In 1 oz. there will be 28.35 x .03 = 0.85 gram protein
In 1 oz. there will be 28.35 x .04 = 1.13 grams fat
In 1 oz. there will be 28.35 x .05 = 1.41 grams sugar

THERMOMETRY

There are two scales used in thermometry, the Fahrenheit and the
Centigrade. The former is generally used. However, since many of the
scientific calculations are made using the Centigrade scale it is wise
for the nurse to understand how to translate one to the other.

Centigrade has 0 deg. as the freezing point and 100 deg. as the boiling point,
while Fahrenheit has 32 deg. as freezing point and 212 deg. as boiling point.
To change Fahrenheit to Centigrade it is necessary to subtract 32 from
212 in order to make the freezing points correspond. This would read
212-32 = 180 deg. F. = 100 deg. C; hence a degree Centigrade represents 5/9
of a degree Fahrenheit.

To change Centigrade to Fahrenheit it is necessary to remember that
every Fahrenheit degree is 9/5 times as large as the Centigrade and
the addition of 32 deg. must also be made. For example: Change 105 deg. F. to
Centigrade: 105 deg.-32 deg. x 5/9 = 41 deg. C. Change 50 deg. C. to Fahrenheit: 50 deg. x
9/5 + 32 deg. = 90 deg. + 32 deg. = 122 deg. F.

FOOTNOTE:

[28] "Diseases of Nutrition and Infant Feeding," by Morse and Talbot.

CHAPTER V

FOOD MATERIALS AND THEIR PREPARATION

~Dairy Products.~--Milk, cream, and other dairy products form such an
important part of the invalid dietary that they require especial care
in their selection. "Certified Milk" is the safest. This is protected
by special inspection. The methods and standards governing the
production and distribution of certified milk were adopted by the
American Association of Medical Milk Commissions, May 1, 1912. The
sanitary condition of the dairy, the cleanliness of the vessels into
which the milk is placed, the health of the milkers, and a surety that
no member of their family wit