_habit_, you may wish to point to a certain acquired skill of the
respiratory and facial muscles, and a certain acquired temper of the
stomach, enabling one to inhale tobacco fumes with impunity.

7. Habits are acquired, but it is obvious that the rate of acquisition
varies in different persons. This comes from one person being more
predisposed by _nature_ than another to the acquiring of this or that
habit. By nature, that is by the native temper and conformation of his
body wherewith he was born, this child is more prone to literary
learning, that to mechanics, this one to obstinacy and
contentiousness, that to sensuality, and so of the rest. For though it
is by the soul that a man learns, and by the act of his will and
spiritual powers he becomes a glutton or a zealot, nevertheless the
bodily organs concur and act jointly towards these ends. The native
dispositions of the child's body for the acquisition of habits depend
to an unascertained extent upon the habits of his ancestors. This is
the fact of _heredity_.

8. Man is said to be "a creature of habits." The formation of habits
in the will saves the necessity of continually making up the mind
anew. A man will act as he has become habituated, except under some
special motive from without, or some special effort from within. In
the case of evil habits, that effort is attended with immense
difficulty. The habit is indeed the man's own creation, the outcome of
his free acts. But he is become the bondslave of his creature, so much
so that when the occasion arrives, three-fourths of the act is already
done, by the force of the habit alone, before his will is awakened, or
drowsily moves in its sleep. The only way for the will to free itself
here is not to wait for the occasion to come, but be astir betimes,
keep the occasion at arm's length, and register many a determination