Daily observation proves the force of the mind’s action upon the stomach; and this every man has an opportunity of experiencing in himself; for the more intensely any man thinks, and the more strongly he exerts the reflecting powers of his mind, the more slowly and with the greater difficulty, _cæteris paribus_, does he digest what he eats; and, on the other hand, the freer a man’s mind is from reflexion, the more readily and the better he digests. It is observable that fools always eat and drink a great deal, and yet digest perfectly well, even though they lead a sedentary life, and do not surpass others either in the bulk or strength of their bodies: whilst men of genius and abilities, though they have strong muscles, and take exercise sufficient, are obnoxious to crudities in the stomach and slowness of concoction [8]. BOERHAAVE, who resided a long time in a city renown’d for learning, has observ’d that studies excite a disagreeable sensation at the upper orifice of the stomach; and that, if this be neglected by the studious, madness ensues[9]. My illustrious friend POME knew a man of learning, who had made his stomach so infirm by intense application, that immediately after eating he vomited[10]. I myself have seen some, who, when their minds were wearied out with constant study, being taken ill, at first lost all appetite, then were seiz’d with a weakness of their whole bodies, and at last with dreadful paroxysms, which began with vomiting, and ended in convulsions and a total privation of their senses.