several
particular_ abilities. The _individual brain unit_ (as of courage,
memory, judgment, etc.) is strengthened only by handling the in and out
business of _its_ coordinated muscles and mind center. Also, while a
particular set of muscles and coordinate mind center are strengthening
their brain center by the exercise they give _it_, they are both being
developed by the same exercise of passing along sense impressions and
thoughts to each other through the brain--like Smith and Brown.

[Sidenote: The Process Of Growth]

Returning to the comparison of Burbank's methods with man development,
we perceive again how the principle of discriminative-selective training
is applied to accomplish the growth of certain characteristics needed
to assure a man's success. The plant wizard in his initial tests gave
to his undeveloped prune trees particular food and conditions and
treatment selected for the purpose of imparting specific qualities of
deliciousness. A prune _somewhat improved_ in deliciousness was
the first result. Then from the product of that _improved_ prune
he started _another_ cycle of development. He fed the selected food
of deliciousness to the improved prune tree, and a fruit _more_
delicious resulted. His work was simply plant breeding by the
discriminative-restrictive method. Brain breeding is a similar process
of _particularized, cumulative_ development.

[Sidenote: Begin With Specific Training of The Outer Man]

All the foregoing rather complicated explanation of "psychological
processes" has seemed necessary to make a clear impression of the _right
training methods_ for building within you any quality you need to assure
your success. You must begin by training your _outer_ man.

You can develop a particular mind-brain center (such as the center of
courage) only by the discriminative-restrictive training of those
portions of your _body_ which are directly related in activity and
responsiveness to that mind-brain unit of the multiplex YOU. Training of
_any other_ set