thematic terms, and this paper is
written with that end in view.

Phenomena of life are phenomena of motion. These motions are maintained
at the expense of chemical energy liberated in the oxidative breakdown
of carbohydrate, fat, and protein. Furthermore, the protein structure of
the body cells and the salts of the bones and other tissues are in a
constant state of wearing down. The energy for the human machine and the
materials for its self-repair are taken in the form of food. The general
term _metabolism_ includes all the chemical activities which take place
under the influence of living cells.

The total quantity of heat produced by the body is a measure of the
intensity of the oxidation of carbohydrate, fat, and protein within the
body.

It is important to know definitely whether there is any constant measure
of the level of the basal metabolism in normal people, so that one may
determine in cases of disease whether the heat production is normal or
increased or decreased.

Rubner discovered that the heat production of mammalia during rest was
the same per square meter of surface whether the being was a horse, a
man, a dog, or a mouse. The proposition has appeared so improbable as to
call forth much antagonism. DuBois deserves the credit of having
established this relationship for man beyond the possibility of a doubt.
He was able to do this on account of his discovery of a new and accurate
method of measuring the area of the body surface. It appears from his
work that the _basal metabolism_ for men between twenty and fifty years
old is approximately 40 calories per hour per square meter of body
surface, within a +/- error of 10 per cent.

Boothby has found that the metabolism of patients who have recovered
their health after hospital operations and who have been confined in the
hospital between twenty and fifty days does not vary from the normal
standard of DuBois.

It has been found by DuBois that the basal metabolism in boys of twelve
is 25 per cent. higher than for an adult of the same height and weight,
or {50} calories per square meter of body surface; and that in boys of
fifteen the metabolism is 11 per cent. higher than for the adult of the
same size and shape, or {44} calories per square meter of body surface
(unpublished work of DuBois). These results explain the large appetites
of boys.

Women show a metabolism which is 7 per cent. lower than that of men, or
{37} calories per hour per square met