[Footnote 1: See, now, "Brain-Work and Overwork," by H.C. Wood, M.D.;
also, "Mental Overwork and Premature Disease among Public and
Professional Men," by Ch. K. Mills, M.D.; also, "Overwork and Sanitation
in Public Schools, with Remarks on the Production of Nervous Disease and
Insanity," by Ch. K. Mills, M.D.,--_Annals of Hygiene_, September,
1886.]

One of our ablest medical scholars reports himself to me as having never
been aware of any sensation in the head, by which he could tell that he
had worked enough, up to a late period of his college career, when,
having overtaxed his brain, he was restricted by his advisers to two or
three hours of daily study. He thus learned to study hard, and ever
since has been accustomed to execute all mental tasks at high pressure
under intense strain and among the cares of a great practice. All his
mind-work is, however, forced labor, and it always results in a distinct
sense of cerebral fatigue,--a feeling of pressure, which is eased by
clasping his hands over his head; and also there is desire to lie down
and rest.

"I am not aware," writes a physician of distinction, "that, until a few
years ago, I ever felt any sense of fatigue from brain-work which I
could refer to the organ employed. The longer I worked the clearer and
easier my mental processes seemed to be, until, during a time of great
sorrow and anxiety, I pushed my thinking organs rather too hard. As a
result, I began to have headache after every period of intellectual
exertion. Then I lost power to sleep. Although I have partially
recovered, I am now always warned when I have done enough, by lessening
ease in my work, and by a sense of fulness and tension in the head."
The indications of brain-tire, therefore, differ in different people,
and are more and more apt to be referred to the thinking organ as it