and inherited habit, other highly complex ones have been developed
through the preservation of variations of pre-existing instincts--
that is, through natural selection.

I have discussed at some little length, though as I am well aware,
in a very imperfect manner, the acquirement of reflex actions,
because they are often brought into play in connection with movements
expressive of our emotions; and it was necessary to show that at least
some of them might have been Erst acquired through the will in order
to satisfy a desire, or to relieve a disagreeable sensation.


_Associated habitual movements in the lower animals_.--
I have already given in the case of Man several instances
of movements associated with various states of the mind or body,
which are now purposeless, but which were originally of use,
and are still of use under certain circumstances. As this subject
is very important for us, I will here give a considerable number
of analogous facts, with reference to animals; although many
of them are of a very trifling nature. My object is to show that
certain movements were originally performed for a definite end,
and that, under nearly the same circumstances, they are still
pertinaciously performed through habit when not of the least use.
That the tendency in most of the following cases is inherited,
we may infer from such actions being performed in the same manner
by all the individuals, young and old, of he same species.
We shall also see that they are excited by the most diversified,
often circuitous, and sometimes mistaken associations.

Dogs, when they wish to go to sleep on a carpet or other hard surface,