M.Flourens first pointed out the fact that certain morbific agents, when introduced into the current of the circulation, tend to act _primarily_ and _specially_ on one nervous centre in preference to that of another, by virtue of some special elective affinity between such morbific agents and certain ganglia.

Thus, in the tottering gait of the tipsy man, we see the influence of alcohol upon the functions of the _cerebellum_ in the impairment of its power of co-ordinating the muscles.
"Certain writers on diseases of the mind make especial allusion to that form of insanity termed DYPSOMANIA, in which a person has an unquenchable thirst for alcoholic drinks--a tendency as decidedly maniacal as that of _homicidal mania_; or the uncontrollable desire to burn, termed _pyromania_; or to steal, called _kleptomania_." HOMICIDAL MANIA.
"The different tendencies of homicidal mania in different individuals are often only nursed into action when the current of the blood has been poisoned with alcohol.

I had a case of a person who, whenever his brain was so excited, told me that he experienced a most uncontrollable desire to kill or injure some one; so much so, that he could at times hardly restrain himself from the action, and was obliged to refrain from all stimulants, lest, in an unlucky moment, he might commit himself.
Townley, who murdered the young lady of his affections, for which he was sentenced to be imprisoned in a lunatic asylum for life, _poisoned his brain with brandy_ and soda-water before he committed the rash act.

The brandy stimulated into action certain portions of the brain, which acquired such a power as to subjugate his will, and hurry him to the performance of a frightful deed, opposed alike to his better judgment and his ordinary desires.
"As to _pyromania_, some years ago I knew a laboring man in a country village, who, whenever he had had a few glasses of ale at the public-house, would chuckle with delight at the thought of firing certain gentlemen's stacks.

Yet, when his brain was free from the poison, a quieter, better-disposed man could not be.