Page:Tropical Diseases.djvu/494

452 alkaline reaction. The eruption usually lasts about a fortnight, and is followed by desquamation, which leaves the skin rough, thickened, and permanently stained of a light sepia colour. It is on account of this roughness of the affected skin that the disease is called " pellagra," an Italian word meaning rough skin.

Implication of the nervous system is indicated by tremor of the tongue, exaggerated deep reflexes, and mid-dorsal spinal tenderness. The patient suffers from obstinate sleeplessness, occasionally from uncontrollable sleepiness. He experiences great weakness, especially in the lower extremities, and is subject to peculiar attacks of giddiness, with a tendency to fall forwards or backwards. Another characteristic symptom is a feeling of ourning in the palms of the hands and the soles of the feet. " Chvostek's sign," mechanical irritability of the facial nerve, is said to be present in the majority of cases.

As a rule there is no marked permanent elevation of temperature, but periods of slight fever occur irregularly. Two or three months after onset the symptoms abate and, although the affected skin areas remain dark-coloured and rough, the disease appears to be arrested. Next spring, however, the whole series of phenomena recurs in a more severe form. The eruption assumes a darker colour. The depression of spirits deepens into melancholia, which may have maniacal interludes, with a peculiar tendency to suicide, especially by drowning. The general feeling of weakness increases, the patient loses weight and is unable to work; his gait becomes uncertain and somewhat of the spastic paraplegic type. The pains in the head and back become very acute, and there may be lightning pains, cramps, twitchings, tremors, and even epileptiform seizures of the cortical variety. Diarrhœa may now be troublesome.

For several years the disease may thus recur in the spring with increasing severity. The patient becomes greatly emaciated, paralytic, and completely demented. Helpless, bedridden, suffering from incontinence of urine and uncontrollable diarrhœa, covered