on of the storing-up and transmission of
energy, Mr. Redfield has fallen victim to a confusion of ideas due to
the use of the same word to mean two different things. He thinks of
energy as an engineer; he declares the body-cell is a storage battery;
he believes that the athlete by performing work stores up energy in his
body (in some mysterious and unascertainable way) just as the clock
stores up energy when it is wound. The incorrectness of supposing that
the so-called energy of a man is of that nature, is remarkable. If,
hearing Bismarck called a man of iron, one should analyze his remains to
find out how much more iron he contained than ordinary men, it would be
a performance exactly comparable to Mr. Redfield's, when he thinks of a
man's "energy" as something stored up by work.

As a fact, a man contains less energy, after the performance of work,
than he did at the start. All of his "energy" comes from the metabolism
of food that he has previously eaten. His potential energy is the food
stored up in his body, particularly the glycogen in the liver and
muscles.[197]

Why, then, can one man run faster than another? Mr. Redfield thinks it
is because the sprinter has, by previous work, stored up energy in his
body, which carries him over the course more rapidly than the sluggard
who has not been subjected to systematic training. But the differences
in men's ability are not due to the amount of energy they have stored
up. It is due rather to differences in their structure (using this word
in a very broad sense), which produce differences in the efficiency
with which they can use the stored-up energy (i.e., food) in their
bodies. A fat Shorthorn bull contains much more stored-up energy than
does a race horse, but the latter has the better structure--cooerdination
of muscles with nervous system, in particular--and there is never any
doubt about how a race between the two will end. The difference between
the results achieved by a highly educated thinker and a low-grade moron
are similarly differences in structural efficiency: the moron may eat
much more, and thereby have more potential energy, than the scholar; but
the machine, the brain, can not utilize it.

The effects of training are not to store up energy in the body, for it
has been proved that work decreases rather than increases the amount of
energy in the body. How is it, then, that training increases a man's
efficiency? It is obviously by improving his "structur