HOW ALCOHOL AFFECTS THE BRAIN.
I once had the unusual, though unhappy, opportunity of
observing the same phenomenon in the brain structure of a man, who, in a
paroxysm of alcoholic excitement, decapitated himself under the wheel of a
railway carriage, and whose brain was instantaneously evolved from the skull by
the crash. The brain itself, entire, was before me within three minutes after
the death. It exhaled the odor of spirit most distinctly, and its membranes and
minute structures were vascular in the extreme. It looked as if it had been
recently injected with vermilion. The white matter of the cerebrum, studded
with red points, could scarcely be distinguished, when it was incised, by its
natural whiteness; and the pia-mater, or internal vascular membrane covering
the brain, resembled a delicate web of coagulated red blood, so tensely were
its fine vessels engorged.
I should add that this condition extended through both the
larger and the smaller brain, the cerebrum and cerebellum, but was not so
marked in the medulla or commencing portion of the spinal cord.
The spinal cord and nerves.
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The action of alcohol continued beyond the first stage, the
function of the spinal cord is influenced. Through this part of the nervous
system we are accustomed, in health, to perform automatic acts of a mechanical
kind, which proceed systematically even when we are thinking or speaking on
other subjects. Thus a skilled workman will continue his mechanical work
perfectly, while his mind is bent on some other subject; and thus we all
perform various acts in a purely automatic way, without calling in the aid of
the higher centres, except something more than ordinary occurs to demand their
service, upon which we think before we perform. Under alcohol, as the spinal
centres become influenced, these pure automatic acts cease to be correctly
carried on. That the hand may reach any object, or the foot be correctly
planted, the higher intellectual centre must be invoked to make the proceeding
secure. There follows quickly upon this a deficient power of co-ordination of
muscular movement. The nervous control of certain of the muscles is lost, and
the nervous stimulus is more or less enfeebled. The muscles of the lower lip in
the human subject usually fail first of all, then the muscles of the lower
limbs, and it is worthy of remark that the extensor muscles give way earlier
than the flexors. The muscles themselves, by this time, are also failing in
power; they respond more feebly than is natural to the nervous stimulus; they,
too, are coming under the depressing influence of the paralyzing agent, their
structure is temporarily deranged, and their contractile power reduced.
This modification of the animal functions under alcohol,
marks the second degree of its action. In young subjects, there is now,
usually, vomiting with faintness, followed by gradual relief from the burden of
the poison.
Effect on the brain centres.
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The alcoholic spirit carried yet a further degree, the
cerebral or brain centres become influenced; they are reduced in power, and the
controlling influences of will and of judgment are lost. As these centres are
unbalanced and thrown into chaos, the rational part of the nature of the man
gives way before the emotional, passional or organic part. The reason is now
off duty, or is fooling with duty, and all the mere animal instincts and
sentiments are laid atrociously bare. The coward shows up more craven, the
braggart more boastful, the cruel more merciless, the untruthful more false,
the carnal more degraded. ' In vino veritas ' expresses, even, indeed, to
physiological accuracy, the true condition. The reason, the emotions, the
instincts, are all in a state of carnival, and in chaotic feebleness.
Finally, the action of the alcohol still extending, the
superior brain centres are overpowered; the senses are beclouded, the voluntary
muscular prostration is perfected, sensibility is lost, and the body lies a mere
log, dead by all but one-fourth, on which alone its life hangs. The heart still
remains true to its duty, and while it just lives it feeds the breathing power.
And so the circulation and the respiration, in the otherwise inert mass, keeps
the mass within the bare domain of life until the poison begins to pass away
and the nervous centres to revive again. It is happy for the inebriate that, as
a rule, the brain fails so long before the heart that he has neither the power
nor the sense to continue his process of destruction up to the act of death of
his circulation. Therefore he lives to die another day.