CHAP. I. SERVICEABLE ASSOCIATED HABITS. 35
9 Prof. Huxley remarks (' Elementary Physiology,' 5th
edit. p. 305) that reflex actions proper to the spinal cord
are natural; hut, by the help of the brain, that is through
habit, an infinity of artificial reflex actions may be ac-
quired. Virchow admits ('Samxnlung1 wissonschaft. Vor-
trJi^e,1 &c., " Ueber das Iliickenmarlv,1' 1871, ss. 24, 31)
that some refkvx actions can hardly be distinguished from
instincts; and, of the latter, it may be added, some cannot
be distinguished from inherited habits.
a pair of scissors may be seen to move their jaws simul- ** \
taneously with the blades of the scissors. Children , , -
learning to write often twist about their tongues as *
their fingers move, in a ridiculous fashion. When a , *
public singer suddenly becomes a little hoarse, many
of those present may be heard, as I have been assured .
by a gentleman on whom I can rely, to clear their " (,'
throats; but here habit probably comes into play, as we ' "; ;
clear our own throats under similar circumstances. %*
I have also been told that at leaping matches, as the t [ •
performer makes his spring, many of the spectators, ^
generally men. and boys, .move their feet; but here
again habit probably conies into play, for it is very
doubtful whether women would thus act.
Reflex aotions.—Reflex actions, in the strict sense of
the term, are due to the excitement of a peripheral
nerve, which transmits its inilucncc to certain nerve- ' ' * *
cells, and these in their turn excite certain, muscles or ^ »
glands into action; and all this may take place without » *
any sensation or consciousness on our part, though often '/»*
thus accompanied. As many reflex actions are highly * »*
expressive, the subject must here bo noticed at some • ( '*
little length. We shall also see that some of thorn / ^ <»
graduate into, and can hardly be distinguished from | f'
actions which have arisen through habit.1* Coughing #,, **•
and sneezing are familiar instances of reflex actions. , ^
With infants the first act of respiration is often a sneeze, , g
although this requires the co-ordinated movement of > < t