5. As long as the pain of the head, the giddiness, and the increased sensibility continue, there is invariably a want of sleep. The degree of sleeplessness is not always in proportion to the head-ache or to the other symptoms; but while the latter are present, the former is never absent. That condition of the brain upon which sleep depends appears to be easily disturbed by a great variety of causes; but whatever be capable of affrighting this heavenly visitant, “tired Nature’s sweet restorer,” whether in the mansion, the palace, or the prison, and whether from the bed of healthful slumber or from the couch of sickness, nothing so effectually and so constantly banishes it as that febrile uneasiness of which we have already spoken; and which, instead of declining, as in the milder form of fever, now increases in strength and activity, and will scarcely allow the restless body to remain in one position for a moment. He who has felt its influence in this stage and degree of fever, will admit that there is nothing comparable to the wretchedness it produces, except it be the sweetness of the first waking moment after the first tranquil slumber of returning health. 6. And now, sometimes closing this train of symptoms, but more frequently being the first harbinger of another, delirium appears. Delirium is usually first observed when any slight sound rouses the patient from that disturbed slumber which is the only substitute allowed for sleep. The delirium is seldom violent or long-continued, but, when present, is like the talking of a person during sleep in a disturbed dream. This symptom, however, is by no means invariably present, and when it does come, it often postpones its visit to a somewhat later period. 7. The pulse, during all this time, may not be much quicker than in the mild form; and the state of the tongue and of the evacuations does not materially differ. Such is the train of symptoms when the brain becomes prominently affected. These symptoms continue without intermission, and with little change, for several days. The period of their duration, when only in this degree of violence, is commonly from eight to ten days: when their character is still milder or more subacute, or when they have been mitigated by appropriate remedies, it may be protracted fifteen days. About this period a remarkable change takes place; an entirely new train of symptoms supervenes, which is different, and which, indeed, presents a striking contrast, according as the patient is destined for life or death.