CASE I.--Some years ago a case similar in several respects to that of Southey came under my observation. A gentleman of superior mind and of great powers of application spent from sixteen to eighteen hours each day in severe literary labor. This of itself would have been a heavy strain to most persons, but he went regularly to bed and slept soundly six hours each night, and it is possible that he might have continued this mode of life for several years without serious inconvenience, when his wife was suddenly taken ill. His anxiety on her account was very great, and he spent nearly the whole night by her bedside, sleeping only for about an hour toward morning. After three weeks passed in this manner, his wife was pronounced out of danger, but he found it impossible to resume his former habits. He could neither study nor sleep. The nights were passed in walking the floor of his chamber or in tossing restlessly on his bed. There were no pain, no fever, no disorder of any other organ. There was nothing but ceaseless activity of the mind and an utter inability to sleep. Stimulants and narcotics only increased the violence of his symptoms, and every other means employed failed to give relief. The danger of his situation was pointed out to him and travel recommended. He followed the advice, and though it was several months before he was completely relieved, his condition began at once to improve. He was taught a lesson which has not been without influence, in causing him to task his mental faculties less severely. CASE II.--Another, an intimate friend, who occupied an important public position, gave so much time and attention to his duties, which were of a highly laborious character, that he deprived himself of the amount of sleep to which he had previously been accustomed. It was rarely the case that he got to bed before two or three o’clock in the morning, and then an hour or two was always occupied in active intellection. The consequence was that he finally broke down through want of the mental repose so essential to him. Inflammation of the brain ensued, and this terminated in acute insanity, from which he died.