great fatigue or over-exertion, or when there is depression of vital power from any cause during exposure to a high temperature. There is depression of nerve-force and of muscular power; the skin is pale, cold, and moist, the pulse feeble. Death may occur in this state from failure of the heart; but complete recovery more frequently occurs. Asphyxia and apnœa (stoppage of the breath) may come on after premonitory symptoms of depression and weakness, during exposure of the head and spine to the direct rays of a powerful sun, when the atmosphere is much heated, and the nervous energy is depressed by over-fatigue, illness, or dissipation. The brain and respiratory nerve centers are overwhelmed by the sudden rise of their temperature, and respiration and circulation fail.
Recovery, though frequently complete, is sometimes tedious and occasionally imperfect, ending in serious impairment of health or intellect.
The symptoms of this form of sunstroke are those of sudden and violent derangement of the nerve-centers, unconsciousness, cold shivers, feeble pulse; all the signs of depression, terminating in death by shock; or fatal reaction may result with a variety of conditions pointing to injury to the cerebro-spinal system. In another class of cases there is ardent fever, the body generally, including the nerve-centers, is heated intensely; this may occur quite independently of the direct action of the sun's rays. It comes on frequently at night, or in the shade, in a building or tent, especially in persons who are depressed by fatigue, bad air, overfeeding, alcoholic stimulants and the consequent depression, want of rest, illness, and notably when the air is impure from overcrowding, or from insufficiency of cubic space.
The temperature of the body may rise to 108°-110°; respiration and circulation fail; there are hurried, gasping respiration, great restlessness; pungently hot skin, sometimes dry, occasionally moist. The pulse varies; in some it is full and laboring, in others quick and jerking; the head, face, and neck are livid and congested; the carotid pulsation is very perceptible; the pupils, at first contracted, dilate widely before death. Coma, stertor, delirium, convulsions frequently epileptiform in character, with relaxation of sphincter, and suppression of urine—these are the precursors of death by asphyxia, and it may be that there is cerebral hæmorrhage.
Such are the cases to which the term heat-apoplexy is given; and a large proportion of the fatal attacks among Europeans in India are so caused. Recovery may partially occur, to be followed by relapse and death, or secondary consequences, the result of tissue-change, may destroy life or impair health and intellect at a later period. The premonitory symptoms of this form of the disease may appear some hours or even days before the dangerous condition just described supervenes. There may be general malaise, disordered secretions, profuse and frequent micturition, restlessness, insomnia (sleeplessness), apprehension
