Until the present generation, the word Insanity was popularly thought
to mean either imbecility on the one hand, or a raving maniac on
the other. We now know that this idea is quite untrue; insanity is
a disease of the mind, just as small-pox is a disease of the body.
Moreover, we speak of insanities, and not insanity; for there are many
varieties--all shading-off one into another. A physician who deals
with such cases is called an “alienist”; and the terms psychiatry,
psycho-pathology, abnormal psychology, etc., are employed to designate
various branches of the study of the diseased mind.
Certain types of insanity are, of course, due to actual brain disease.
A degeneration of the physical substance of the brain may have taken
place. In other cases, however, no such gross degeneration can be
traced, and we must assume microscopic alterations, or blood changes,
or nerves improperly functioning, or purely physical changes and
dissociations, as explained above. There has grown-up an extensive
literature on insanity, within the past few years. A good primary book
of this character is Dr. Bernard Hart’s “Psychology of Insanity.” See
also Dr. Charles Mercier’s “Sanity and Insanity.”