are NATURAL; but, by the help of the brain, that is through habit,
an infinity of ARTIFICIAL reflex actions may be acquired.
Virchow admits (`Sammlung wissenschaft. Vortrage,' &c., "Ueber
das Ruckeninark," 1871, ss. 24, 31) that some reflex actions
can hardly be distinguished from instincts; and, of the latter,
it may be added, some cannot be distinguished from inherited habits.

We see the difference between reflex and voluntary movements in
very young children not being able to perform, as I am informed by
Sir Henry Holland, certain acts somewhat analogous to those of sneezing
and coughing, namely, in their not being able to blow their noses (i. e.
to compress the nose and blow violently through the passage),
and in their not being able to clear their throats of phlegm.
They have to learn to perform these acts, yet they are performed
by us, when a little older, almost as easily as reflex actions.
Sneezing and coughing, however, can be controlled by the will only
partially or not at all; whilst the clearing the throat and blowing
the nose are completely under our command.


[10] "Dr. Maudsley, `Body and Mind,' 1870, p. 8.

When we are conscious of the presence of an irritating particle
in our nostrils or windpipe--that is, when the same sensory
nerve-cells are excited, as in the case of sneezing and coughing--
we can voluntarily expel the particle by forcibly driving air
through these passages; but we cannot do this with nearly
the same force, rapidity, and precision, as by a reflex action.
In this latter case the sensory nerve-cells apparently excite
the motor nerve-cells without any waste of power by first