om knocking at his door. He may drive such images
from his mind the moment they are discovered, and indeed is guilty if he
does not; but not taking offense at this rebuff, the unwelcome thought
again seeks admission.

The only protection against the return of the undesirable associations
is to choose lines of thought as little related to them as possible. But
even then, do the best we may, an occasional "connection" will be set
up, we know not how, and the unwelcome image stands staring us in the
face, as the corpse of Eugene Aram's victim confronted him at every
turn, though he thought it safely buried. A minister of my acquaintance
tells me that in the holiest moments of his most exalted thought, images
rise in his mind which he loathes, and from which he recoils in horror.
Not only does he drive them away at once, but he seeks to lock and bar
the door against them by firmly resolving that he will never think of
them again. But alas! that is beyond his control. The tares have been
sown among the wheat, and will persist along with it until the end. In
his boyhood these images were given into the keeping of his brain cells,
and they are only being faithful to their trust.

ASSOCIATION BY SIMILARITY AND CONTRAST.--All are familiar with the fact
that like tends to suggest like. One friend reminds us of another friend
when he manifests similar traits of character, shows the same tricks of
manner, or has the same peculiarities of speech or gesture. The telling
of a ghost or burglar story in a company will at once suggest a similar
story to every person of the group, and before we know it the
conversation has settled down to ghosts or burglars. One boastful boy is
enough to start the gang to recounting their real or imaginary exploits.
Good and beautiful thoughts tend to call up other good and beautiful
thoughts, while evil thoughts are likely to produce after their own
kind; like produces like.

Another form of relationship is, however, quite as common as similars in
our thinking. In certain directions we naturally think in _opposites_.
Black suggests white, good suggests bad, fat suggests lean, wealth
suggests poverty, happiness suggests sorrow, and so on.

The tendency of our thought thus to group in similars and opposites is
clear when we go back to the fundamental law of association. The fact is
that we more frequently assemble our thoughts in these ways than in
haphazard relations. We habitually group similars toget