e volition of certain
individuals, as distinguished from the timid apprehensiveness that
constantly depresses the powers of others, is connected, not with any
view of external conditions appreciable by the intellect, but with a
vast multitude of vague bodily sensations, of which each alone fails to
make a distinct impression upon consciousness.

4th. An impression made on one part of the sympathetic system is easily
communicated to another, and to the ganglionic masses of the visceral
plexuses, already described. Hence the rapid effect of many emotions
upon the processes of digestion; hence the epigastric response to the
emotion of fear, which led Bichat to localize this feeling in the solar
plexus lying behind the stomach. In a precisely similar manner may the
effect of emotion be distributed to the ganglionic nerves of the
kidneys, uterus, and ovaries, leading to the flow of urine that
terminates a paroxysm of hysteria, often suppressing menstruation, by
contraction of uterine blood vessels, or causing an excess of menstrual
haemorrhage, from an excessive excitement of the ovarian nerves during
the menstrual crisis. None of these effects are observed after a simple
act of thinking, unattended by emotion.

5th. Probably on account of such an influence upon the vaso-motor
nerves, the blood vessels, and, consequently, the processes of
nutrition, the evolution of emotions is attended with much greater
fatigue than is that of thought. The fatigue that may follow a prolonged
intellectual operation is, moreover, distinctly localized in the head,
and exists in various degrees, from simple inability for further
attention, to decided sensation of weariness, or even pain. But the
fatigue experienced after excessive emotion, especially if this be of a
depressing character and accompanied by tears (which imply vaso-motor
paralysis in the lachrymal glands), is generalized all over the body,
and is, moreover, very much more often followed by headache, or by
symptoms of cerebral congestion or anemia, than is the act of thinking,
except in persons morbidly predisposed. When nervous exhaustion is
observed after prolonged mental effort, one of two other conditions, or
both, has nearly always co-existed, namely, deficiency of physical
exercise, or presence of active emotion, as, ardent ambitions or
harassing anxieties. In a few cases, the mental effort itself, by the
afflux of blood determined to the brain, or the excessive activity
im