lution of salt, is
placed on the tender skin, the feet are moved as if to take away the
irritating substance. This of course shows that reflex action can
take place independently of the brain.

Now if the spinal cord is also destroyed, there is no response when
the irritation of the skin is repeated. The animal remains perfectly
quiet, because the destruction of the cord has interrupted the
reflex action pathway. This shows that some part of the central
nervous system is necessary to reflex action.

107 Review description of the spinal nerves, page 295.

108 Where a deep-seated cause for worry exists, there may be occasion
for grave concern. Many people have become insane through continued
worry about some _one_ thing. In cases of this kind the sufferer
needs the aid of sympathetic friends, and sometimes of the
physician, in getting the mind away from the exciting cause. A
change of scene, a visit, or some new employment is frequently
recommended, where the actual cause for the worry cannot be removed.

109 Any part of the body which is overworked or which works at a
disadvantage tends to disturb, more or less, the entire nervous
system and to produce nervousness. Especially is this true of such
delicate and highly sensitive structures as the eyes. If the eyes do
not focus properly or if the muscles that move the eyeballs are out
of their natural adjustment, extra work is thrown upon these
delicate parts. One of the first and sometimes the only indication
of eye strain is that of some disturbance of the nervous system. For
this reason it is important to carefully test the eyes in
determining the cause of nervousness (page 385).

110 One form of neck exercise recommended for this purpose is easily
taken on retiring at night. Lying flat on the back, without a
pillow, lift the head slowly from the bed and let it as slowly
settle back to the level of the body. Repeat several times, lying on
the back, and then again on the face and again on each side.
Practice these exercises every night during an interval of a month
or until relief is secured.

111 Insurance statistics show that habitual _moderate drinkers_ do not
live so long as abstainers.

112 Organs very frequently affected by tobacco are the heart and the
eyes. It ind