in a great vivarium; and these combined opportunities have covered
a long series of years.

Before proceeding farther, it is desirable to define certain terms
that frequently will be used in these pages.

THE ANIMAL BRAIN is the generator of the mind, and the clearing-
house of the senses. As a mechanism, the brain of man is the most
perfect, and in the descent through the mammals, birds, reptiles,
amphibians and fishes, the brain progressively is simplified in
form and function.

THOUGHT is the result of the various processes of the brain and
nervous system, stimulated by the contributions of the senses.

SANITY is the state of normal, orderly and balanced thought, as
formulated by a healthy brain.

INSANITY is a state of mental disease, resulting in disordered,
unbalanced and chaotic thought, destitute of reason.

REASON is the manifestation of correct observation and healthful
thought which recognizes both cause and effect, and leads from
premise to conclusion. INTELLIGENCE is created by the possession
of knowledge either inherited or acquired. It may be either latent
or active; and it is the forerunner of reason.

INSTINCT is the knowledge or impulse which animals or men derive
from their ancestors by inheritance, and which they obey, either
consciously or subconsciously in working out their own