Several cases of insomnia, the result of disordered menstruation, have come under my observation. We can very well understand how, in women suffering from suppression of this function, a slight degree of cerebral hyperæmia and consequent wakefulness should result. About the climacteric time of life, when irregularities in the menstrual flow are very common, there is quite generally extreme sleeplessness as each period approaches, which is not ordinarily relieved till the catamenia make their appearance. In such cases measures directed to the relief of the existent congestion of the brain will generally prove effectual in causing natural sleep. Irregular or deficient action of the heart and blood-vessels is a frequent cause of wakefulness. One of the principal results of such disordered action of the circulatory organs is coldness of the extremities, and an attendant condition of repletion of the central vessels. As a consequence there is in these cases almost invariably great wakefulness. As Dr. Cheyne[140] has remarked, many a delicate female, from going to bed with cold feet, is deprived of hours of sleep in the early part of the night, and thereby falls into nervous complaints, obstinate dyspepsia, and uterine irregularity, who might have escaped had the circulation of the surface of the body been properly sustained. There are cases, however, of habitual cold feet, accompanied by wakefulness, which are not so much due to deficient power in the heart as to disordered nervous action. But, whatever the cause, there is always, while the condition exists, an excessive amount of blood in the cranial vessels. An instance of the kind came under my observation several years ago in the person of an army officer, of strong constitution and otherwise of good health. Heat applied to the extremities gave only temporary relief, and stimulants taken internally were equally inefficacious. He was finally entirely cured by the repeated passage of the direct galvanic current through the sciatic and crural nerves and their branches. Indigestion is quite a common cause of wakefulness, even when no marked disagreeable sensations are experienced in the digestive organs. A full meal, especially if it be of highly seasoned or otherwise improper food, will often keep the offending individual awake the greater part of the night. We know that apoplexy is especially apt to occur soon after the stomach has been overloaded with food. The return of the blood from the head is impeded, and the rupture of an intercranial vessel, or an effusion of serum, is the result of the cerebral congestion. Insomnia is a milder effect of the same cause.