Sleep favors the occurrence of certain pathological phenomena. Thus individuals affected with hæmorrhoids have the liability to hemorrhage increased when they are asleep. Several instances of the kind have come under my notice. In one the patient lost so large a quantity of blood that syncope ensued and might have terminated fatally had not his condition been accidentally discovered. Bleeding from the lungs is also more apt to occur during sleep in those who are predisposed to it. Darwin states that a man of about fifty years of age, subject to hæmorrhoids, was also attacked with hæmoptysis three consecutive nights at about the same hour--two o’clock--being awakened thereby from a state of very profound sleep. He was advised to suffer himself to be roused at one o’clock, and to leave his bed at that hour. He did so with the result not only of entirely breaking up the hemorrhagic disposition, but also of curing himself of very violent attacks of headache, to which he had been subject for many years. Epileptic fits are also more liable to occur during sleep than at other times, a fact not always susceptible of easy explanation. In a case of epilepsy now under my charge, this proclivity is so well marked that the patient, a lady, scarcely ever goes to sleep without being attacked. Her face becomes exceedingly pale just before the fit, and if then seen the paroxysm can be entirely prevented by waking her. She is never attacked at other times, and I am trying, with excellent results thus far, the plan of making her sleep altogether during the day and of waking her as soon as her face becomes pallid. It is probable that the fits in her case are due to a diminished amount of blood in the brain, and this supposition is strengthened by the additional fact that bromide of potassium--a substance which, as I have shown, lessens the amount of intracranial blood--invariably rendered her paroxysms more frequent and severe. Sleep predisposes to attacks of gout in those who have the gouty diathesis, and likewise favors exacerbations in several other diseases which it is scarcely necessary to allude to specifically. The accession of fever toward night, and the increase which takes place in pain due to inflammation are generally associated with the approach of night, and have no direct relation with sleep. Certain other morbid phenomena, such as somnambulism and nightmare, which have a necessary relation with sleep, will be more appropriately considered in another place. On the other hand, sleep controls the manifestations of several diseases, especially those which are of a convulsive or spasmodic character. Thus the paroxysms of chorea cease during sleep, as do likewise the spasms of tetanus and hydrophobia. Headache is also generally relieved by sleep, though occasionally it is aggravated. CHAPTER IV. THE STATE OF THE MIND DURING SLEEP.