Some writers have ranged under this term all those customary habits and
actions which are common to all the individuals of a species. According
to this definition, almost every action of animated life is
instinctive. But the general idea of an instinctive action is much more
restricted; it is one that is performed without instruction and prior
to experience,--and not for the immediate gratification of the agent,
but only as the means for the attainment of some ulterior end. To apply
the term instinct to the regular and involuntary movements of the
bodily organs, such as the beating of the heart and the action of the
organs of respiration, is manifestly an extension of the ordinary
acceptation of the term. Organic actions of a similar character are
also performed by plants, and are purely mechanical. "In the lowest and
simplest class of excited movements," says Mueller, "the nervous system
would not appear to be concerned. They result from stimuli directly
applied to the muscles, which immediately excite their contractility;
and they are evidently of the same character with the motions of
plants." Thus, the heart is excited to pulsation by the direct contact
of the blood with the muscle. The hand of a sleeping child closes upon
any object which gently touches the palm.
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