strength of muscles we must use them. This is just as true of mental
and moral faculties as it is of the physical body. The only way to
make the brain keen and powerful is to exercise it by original
thinking. One way to gain soul powers is to give free play to the
loftiest aspirations of which we are capable, and to do it
systematically instead of at random. We grow to be like the things we
think about. Now, the reverse of all this must be equally true. To
give no thought to higher things, to become completely absorbed in
material affairs, is to stifle the soul, to invite spiritual atrophy.

Turning our attention to nature we shall find in the parasite
convincing proof of all this. The parasite, whether plant or animal,
is living evidence that to refuse or neglect to use an organ or
faculty results in being deprived of it. The dodder, says Drummond,
has roots like other plants, but when it fixes sucker discs on the
branches of neighboring plants and begins to get its food through
them, its roots perish. When it fails to use them it loses them. He
also points to the hermit-crab as an illustration of this great fact
in nature, that disuse means loss, and that to shirk responsibility is
the road to degeneration. The hermit-crab was once equipped with a
hard shell and with as good means of locomotion as other crabs. But
instead of courageously following the hardy life of other crustaceans
it formed the bad habit of taking up its residence in the cast-off
shells of mollusks. This made life easy and indolent. But it paid the
price of all shirking. In time it lost four legs, while the shell over
the vital portion of its body degenerated to a thin membrane which
leaves it practically helpless when it is out of its captured home.
And this is the certain result of all shirking of responsibility.
There may be an apparent temporary gain, but it always means greater
loss, either immediate or remote. So nature punishes inaction with