y bettered and
strengthened in coordination, just as the physical man is developed by
training his various muscles.

You know you have _distinct sets of muscles_ which all together make up
your _composite body_. Perhaps, however, you have not realized before
that your _mind_ is not a _unit_, but is made up of innumerable distinct
"mind centers," each of which functions as independently of the others
as your set of eye muscles operates independently of the set of muscles
governing the movements of one of your fingers. And possibly you do not
know that each _mind_ center has a distinct _brain_ center, which
functions for that _particular part alone_ of your whole mind. _Each
associated mind-and-brain center_ also has direct, distinct nerve
connections _with only one set of muscles_.

In fact, you are "a many-minded, many-bodied" man--a collection of
mental and physical _parts_, a composite man rather than a man unit.
These several parts are in large measure practically _independent_ of
one another. One set of body parts "belongs to" only its particular
associated set of mind parts, or mind center.

[Sidenote: Independent Mind and Body Centers]

If you were constituted otherwise, your life would be very precarious;
for the injury or destruction of even a minor part of your body would be
fatal to the whole unit. As it is, you can lose a finger without
affecting your eye-sight in the least. So you might suffer a localized
brain injury that would completely paralyze a finger, without impairing
your sight at all. Either the mind center that governs a finger, or the
set of muscles in that finger can be affected without necessarily
reacting upon any _other_ mind center or any _other_ set of muscles.

[Sidenote: Interrelation Of the Ego And Physical Man]

_But if the mind center that governs a certain set of muscles is
affected, that set of muscles also is directly affected and at once.
Likewise if anything happens to a particular set of muscles, the
reaction is instantly transmitted to its associated mind center through
the "direct wire" nerves and brain center which particularly serve that
part of the mind_.

Great scientists have studied mental and physical phenomena in
inter-relation and have learned certain facts. For example, it is known
that "the mind" not only affects the general functions of "the body,"
but also the rate of bodily activity and the chemistry of body tissues.
Long-continued hard thinking actually d