in,
represents the lowest degree of disorder, which, if long continued,
passes to the next--of vaso-motor paralysis, accompanied by excessive
haemorrhage; and finally may, as Dr. Clarke has pointed out, be followed
by paralysis in the ovarian plexus itself, with consequent cessation of
ovulation, and amenorrhea, or absence of menstruation.

This habitual predominance or irregularity of the ganglionic nerves
implies, as has been seen, a relatively deficient innervation or
generation of nerve-force in the cerebro-spinal system. It could not,
therefore, be ascribed to excessive activity of that system, except in
the cases where this has been pushed to the point of complete
exhaustion. It is, in fact, a matter of common observation, that
hysterical and anemic women, in whom disordered menstruation is most
frequently observed, are conspicuously destitute of habits implying
either cerebral or spinal activity--that is, they neither think much,
nor take much physical exercise.

The last two cases, however, of cerebro-spinal excitement or exhaustion,
may be supposed to imply a predominant activity of the cerebro-spinal
system.

Inquiry into the effects of cerebro-spinal excitement is rendered
extremely complicated on account of the following facts:

1st. Experimental excitation, by means of galvanism or mechanical
irritation, causes different results when applied to spinal nerves, to
different parts of the spinal cord, or to different parts of the brain.
Galvanism applied to a spinal nerve, determines, it has been said,
dilatation of blood-vessels, and increased secretion in glands. But
galvanism applied to the spinal cord in the neck, causes contraction of
blood-vessels. Mechanical irritation of other parts of the spinal cord,
on the other hand, causes vaso-motor paralysis and dilatation of
blood-vessels. This is especially true of that part lying in the loins,
and which contains a peculiar nervous centre, that stands in special
relation to the uterus and ovaries, and is involved in many of their
diseases, either as a cause or effect. Systematic galvanic irritation of
the brain has been little attempted, until in some very recent
experiments; but its effects are already known to be most various,
according to the part to which it is applied. The brain is not a single
organ, but rather a collection of organs, differing from one another in
function even more than in situation, and among them only some are
really concerned in