In reference to this form of wakefulness, Dr. Handfield Jones[139] makes some judicious observations. He says: “A girl recently under my care with very various and marked signs of prostration of nerve-power, suffered for many months with exceedingly restless nights, the cause of which appeared to be chiefly great hyperæsthesia. Although she improved materially in other respects, she did not sleep well until she was removed from London to a healthy part of the country. I have had several patients, two especially, both temperate males, who for a length of time were quite dependent for good rest at night on wine taken either on going to bed or in the course of the night. * * * It is not easy to form a precise idea of the state of the nervous centers in which a ‘nightcap,’ as above mentioned, is so effectual in procuring sleep. Debility is certainly one marked pattern of it, but there must be surely another, even more important, as the most profound debility does not, by any means, always interfere with sound sleep, nay, rather seems to conditionate it. This other element, we are much disposed to think, is hyperæsthesia, or irritability, which, as already noticed, commonly increases _pari passu_ with weakness. The condition may be compared with that of neuralgia, when it is beginning to give way under treatment, and is so readily reproduced by anything which causes exhaustion. Now, as the stimulant recruits the exhausted nerve force, the hyperæsthesia ceases, and the brain tissue subsides into a state of calm repose. It may be added here that it is often well to give not only a stimulant, but also some digestible nourishment about the time of going to rest, or even in the course of the night when debility to a serious extent exists. It is quite certain that a craving empty stomach is by no means favorable to quiet slumber, and in this point of view moderate suppers are far from being unsuitable to many invalids. I well remember the case of a lady who, the night after a natural confinement, woke up with severe gastric disorder and flatulence, which resisted various medications, but subsided immediately after a plate of cold meat and some brandy and water. Among the various soporifics, I doubt if there be any more potent, especially for the weakly and hyperæsthetic, than prolonged exposure to the cold open air. This should be so managed as not to cause great fatigue, and if well timed and followed by a sufficient meal, it will be found an admirable preparation for sound nightly slumber.” In the foregoing remarks it is perceived that Dr. Jones fails to recognize the state of passive congestion of the brain which in cases such as he describes, and in many similar ones which have come under my care, is almost invariably present. It is this feature which, in addition to the debility, gives so marked a character to the species of insomnia under consideration. The hyperæsthesia, like the wakefulness, is merely a result of the cerebral hyperæmia.