FOOD VALUES 157 
cent. of water with a little salts. It will thus be seen how very 
necessary are proteids (albuminoids), carbon and water. Nitro- 
genous foods, proteids or albuminoids—three names that cover one 
class of food—are found in a variety of substances, particularly 
in meat, fish, peas, beans, milk and cheese, but many vegetables, 
especially cabbage, also contain small proportions of nitrogen. 
Fats and oils are termed hydrocarbons, and they provide energy 
and heat. If fats are not provided the albuminoids will be decom- 
posed in the body of the bird and converted into hydrocarbons to 
make up for the deficiency of fats, but this is a tax on the bird and 
a waste of albuminoids, so it is desirable that the bird get a suffi- 
ciency of oils orfats. Just as hydrocarbons contain much carbon, 
so do the carbohydrates contain less carbon, the same proportion 
of oxygen and hydrogen as is found in water. But while the 
former form part of the body of the bird, the carbohydrates do not, 
unless where fats are deficient they may be chemically broken up 
to supply the necessary fat. They can to a certain extent take 
the place of albuminoids or hydrocarbons, although this is not 
their primary function. These three classes of foods are largely 
supplementary to each other, but only in case of default of any 
one of them, and it is most desirable that albuminoids, carbo- 
hydrates and hydrocarbons should all be supplied in their proper 
proportions. Where fowls have access to grass or arable land no 
special supply of salts and minerals need be given, excepting 
perhaps in the case of growing young birds, where bone meal will 
supply a great demand for phosphates and lime. 
Enough cannot be said about a liberal and constant supply of 
water, for the bird’s body, as well as the egg, contains about 75 
per cent. of moisture. Water is the cheapest—and often most 
neglected—of fowls’ food. Any neglect is punished by a lowering 
of the bird’s health and a falling off in the egg supply. On all 
fowl-houses should be written in large letters : “ Pure water makes 
eggs.” 
Here then is the way to arrive at the proper proportion of foods 
—called the albuminoid ratio : 
The important nutrients in foods are albuminoids, fats and 
