rors during this period may only appear to
exert a local influence, causing disturbance which may readily be
relieved, but the danger is in laying too little stress upon these
disturbances, forgetting that the delicate organism of a child may be
permanently injured by a constant disregard of nature's mandates. In
the words of the old adage, the pitcher may go once too often to the
well, and an injured digestive apparatus is even more difficult to
mend than the proverbial pitcher.

In this section, then, the metabolic changes due to pathological
conditions and the dietetic treatment thereof will be discussed.

~Age and Weight.~--As has already been stated, there are certain
points to be kept in mind in attempting to provide an adequate diet
for the human machine; _First_, the _age_ and _weight_. The gain
during infancy should be steady--an allowance of 40 calories per pound
of body weight to cover the energy requirements and 4 protein calories
per pound to cover the nitrogen needs. During the second and third
years the energy requirements will be covered by 30 to 40 calories per
pound and the nitrogen needs by 3 to 4 protein calories per pound.
From the fifth to the eighth year the nitrogen needs continue to be
covered by 3 to 4 protein calories per pound and the energy
requirements by 35 to 37 calories per pound during the fifth year; 32
to 34 calories per pound during the seventh year. After the body has
reached its full development its requirements will be met if
sufficient protein is provided to cover its maintenance needs and if
the energy calories are regulated according to the amount of exercise
taken, keeping in mind that the energy requirements of a man at rest
(sitting) will be about 2,000 calories per day and that exercise,
especially that taken in the open air, raises the energy needs of the
body.

~Daily Gain.~--In estimating the relative daily gain in body weight of
children of different ages, Mendel[64] gives the following table:

TABLE

In the first month, about 1.00 per cent
At the middle of the first year 0.30 per cent
At the end of the first year 0.15 per cent
At fifth year 0.03 per cent
Maximum in later years for boys 0.07 per cent
Maximum in later years for girls 0.04 per cent

~Retention of Nitrogen in Infancy.~--When the baby is gaining in
weight and strength there is a retention of both nitrogen and salts,
and when the baby is not ga