called "automatic" powers and ways, even of higher animals, to
dogmatize regarding the acts of lower animals, but we may safely
assume that one apparent ground or distinction between instinct and
reason may be found in the common incompetence of instinct to move out
of the beaten track of existence, and in the adaptation of reason,
through the teachings of experience, to new and unwonted
circumstances. Let Dr. Carpenter speak as an authority on such a
subject. "The whole nervous system of invertebrated animals, then, may
be regarded as ministering entirely to _automatic_ action; and its
highest development, as in the class of insects, is coincident with
the highest manifestations of the 'instinctive' powers, which, when
carefully examined, are found to consist entirely in movements of the
excito-motor and sensori-motor kinds. (The terms '_excito-motor_' and
'_sensori-motor_' are applied to nervous actions resulting in
movements of varying kinds, and produced by impressions made on
nervous centres, but without any necessary emotion, reason, or
consciousness.) When we attentively consider the habits of these
animals, we find that their actions, though evidently adapted to the
attainment of certain ends, are very far from evincing a _designed_
adaptation on the part of the beings that perform them.... For, in the
first place, these actions are invariably performed in the same manner
by all the individuals of a species, when the conditions are the same;
and thus are obviously to be attributed rather to a uniform impulse
than to a free choice, the most remarkable example of this being
furnished by the economy of bees, wasps, and other 'social' insects,
in which every individual of the community performs its appropriated
part with the exactitude and method of a perfect machine. The very
perfection of the adaptation, again, is often of itself a sufficient
evidence of the unreasoning character of the beings which perform the
work; for if we attribute it to their own intelligence, we must admit
that this intelligence frequently equals, if it does not surpass, that
of the most accomplished Human Reasoner."

Appealing to the most recent observations on ants, we may find
evidence of the truth of Dr. Carpenter's statements, whilst at the
same time we may also detect instances of the development of higher
powers which are hardly to be classed as "automatic," and which, in
certain species (as in the _Ecitons_, charmingly described by