In this case I conceived that the blood-vessels of the brain, from overdistention, had lost, in a great measure, their contractile power, and that a larger quantity of blood was, in consequence, circulating within the cranium than was normal. The vessels were therefore in a condition very similar to that of a bladder in which, from the desire to urinate having been too long resisted, contraction cannot be induced even by the most strenuous exertion of the will. As the gentleman was of strong, athletic build, and otherwise in full health, blood-letting would undoubtedly have proved of great service; but, for reasons which will appear hereafter, I determined to try a remedy less likely to do harm, and fully as capable of doing good. I administered thirty grains of the bromide of potassium at six o’clock in the evening, and repeated the dose at ten, directing him to go to bed half an hour subsequently. The first dose produced a decided sedative action, and the second was still more effectual in calming the mental excitement. When he lay down, his mind was not disturbed by a flow of thoughts, and he fell almost unconsciously into a quiet sleep, from which he did not awake till near seven o’clock the following morning. There were no unpleasant symptoms of any kind; on the contrary, he felt strengthened and refreshed. The next night one dose was administered at about bedtime, which was also followed by a sound and invigorating sleep. No further treatment was given, as on the following night sleep came naturally. Sir Benjamin Brodie,[128] without, however, making the distinction I have insisted upon, refers to the active or sthenic type of wakefulness in the following quotations from a little work which should be in the hands of all who are interested in the philosophy of the mind. Speaking of the causes of the wakefulness of some persons, he says: “At the same time there is no doubt that there is sometimes a morbid condition of the nervous system, the nature of which we cannot well explain, which is incompatible with sleep. The patient says, ‘I feel fatigued and wearied and want to go to sleep, but I cannot sleep.’” In asserting as he does that this kind of wakefulness is sometimes the forerunner of mental derangement, Sir Benjamin is supported by many cases detailed by authors on psychological medicine, and the following, which he gives,[129] is directly to the point: