ng upon theories of the origin of
instinct and of its place in animal life.

_Theories of Instinct._--Apart from the older view which saw in animal
instinct simply a matter of original created endowment, whereby each
animal was made once for all "after his kind," and according to which
there is no further reason that the instincts are what they are than
that they were made so; apart from this "special creation" view, two
different ideas have had currency, both based upon the theory of
evolution. Each of these views assumes that the instincts have been
developed from more simple animal actions by a gradual process; but
they differ as to the elements originally entering into the actions
which afterward became instinctive.

1. First, there is what is called the Reflex Theory. This holds that
instincts are reflex actions, like the closing of the eye when an
object threatens to enter it, only much more complex. They are due to
the compounding and adding together of simple reflexes, in greater and
greater number, and with increasing efficiency. This theory attempts
to account for instinct entirely in terms of nervous action. It goes
with that view of evolution which holds that the nervous system has
had its growth from generation to generation by the continued reflex
adjustments of the organism to its environment, whereby more and more
delicate adaptations to the external world were secured. In this way,
say the advocates of this theory, we may account for the fact that the
animal has no adequate knowledge of what he is doing when he performs
an act instinctively; he has no end or aim in his mind; he simply
feels his nervous system doing what it is fitted to do by its organic
adaptations to the stimulations of air, and earth, and sea, whatever
these may be.

But it may be asked: Why do succeeding generations improve each on its
parents, so that there is a gradual tendency to perfect the instinct?

The answer to this question brings up another great law of
biology--the principle of Variations. This principle states the common
fact that in every case of a family of offspring the individual young
vary slightly in all directions from their parents. Admitting this, we
will find in each group of families some young individuals which are
better than their parents; these will have the advantage over others
and will be the ones to grow up and have the children of the next
generation again, and so on. So by constant Variation and N