Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: teeth and evacuation of many pockets of pus. J3LEEP AND FATIGUE Insomnia.—Insomnia is a symptom rather than a disease, and although it is not invariable in the neuro-psychoses it may be considered as practically the recurring link which binds them together. In order to understand the phenomena of insomnia, it is necessary to make at least a tentative definition of sleep. Whatever else sleep may be, it must be mainly unconsciousness, though not alone a modification of cortical function. This is attested by the fact that the cortical centres of memory sometimes continue their activity during sleep and that the motor and even the perceptive centres are active in somnambulism. The negative element of sleep, rest through inactivity, is possible in varying intervals to all the tissues of the body. The active part of the process is peculiar to the brain, which shares the inactivity andadds disjunction of the higher from the lower ganglionic levels in degree varying with the profoundness of the sleep. Thus comparative rest is compatible with waking. Considerable activity may go on in the dormant condition, but this activity contains a relatively small amount of interchange between the ganglionic levels. The subjective element of insomnia is necessarily the conscious activity of the cortex. The natural inference is that sleep is banished because the cortical processes of perception and thought go on. An objective study, however, of cases of insomnia shows clearly its frequent dependence on the activity of the lower centres. Comparison of the cases just cited discloses the fact that proto- pathic irritation is accompanied by insomnia in the majority of instances. If the patient makes his insomnia an object of study he very often finds that wake- fulness is persistent without tho...