he initial action or
sensation brings the ideas of all the rest crowding into consciousness:
producing, in some degree, the pleasures or pains that have before been
felt in reality. And when this relation, besides being frequently
repeated in the individual, occurs in successive generations, all the
many nervous actions involved tend to grow organically connected. They
become incipiently reflex; and, on the occurrence of the appropriate
stimulus, the whole nervous apparatus which in past generations was
brought into activity by this stimulus, becomes nascently excited. Even
while yet there have been no individual experiences, a vague feeling of
pleasure or pain is produced; constituting what we may call the body of
the emotion. And when the experiences of past generations come to be
repeated in the individual, the emotion gains both strength and
definiteness; and is accompanied by the appropriate specific ideas.

This view of the matter, which we believe the established truths of
Physiology and Psychology unite in indicating, and which is the view
that generalizes the phenomena of habit, of national characteristics, of
civilization in its moral aspects, at the same time that it gives us a
conception of emotion in its origin and ultimate nature, may be
illustrated from the mental modifications undergone by animals. On
newly-discovered lands not inhabited by man, birds are so devoid of fear
as to allow themselves to be knocked over with sticks; but in the course
of generations, they acquire such a dread of man as to fly on his
approach; and this dread is manifested by young as well as by old. Now
unless this change be ascribed to the killing-off of the less fearful,
and the preservation and multiplication of the more fearful, which,
considering the comparatively small number killed by man, is an
inadequate cause; it must be ascribed to accumulated experiences; and
each experience must be held to have a share in producing it. We must
conclude that in each bird which escapes with injuries inflicted by man,
or is alarmed by the outcries of other members of the flock (gregarious
creatures of any intelligence being necessarily more or less
sympathetic), there is established an association of ideas between the
human aspect and the pains, direct and indirect, suffered from human
agency. And we must further conclude that the state of consciousness
which impels the bird to take flight, is at first nothing more than an
ideal reprod