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XLVI] sulphur fumes, act very slowly and unsatisfactorily. Clothes should be boiled or burned.

Prophylaxis. Daniels informs me that tinea imbricate is a comparatively rare disease in Tonga. This circumstance the natives attribute to their custom of oiling the body. Daniels remarks that of late years, since the Fijians adopted the same practice, the disease has become somewhat less prevalent among them. Personal cleanliness, and the immediate and active treatment of any scaling spot, should be carefully practised in the endemic countries.

In Tahiti the use of chrysophanic acid is now general among the natives; as a consequence the disease is not so prevalent there as it was only a few years ago.

Definition.— An epiphytic disease characterized by peculiar pigmented patches on the skin. Geographical distribution.— In certain districts in tropical America, especially along the river banks in Mexico, Central America, Venezuela, Colombia, Bolivia, and one or two places in Peru, Chile, and Brazil— the district between the Juciparana and the Santo Antonio rivers (Magalhães, private letter)— there occurs an epiphytic skin disease characterized by peculiar red, or blue, or black, or white piebald spotting of the skin of a part, or of the whole, of the body. The patient emits an offensive odour, sometimes compared to that of a mangy dog or of dirty linen. Desquamation and itching of the patches are also features of the disease. It entails no constitutional disturbance and no danger to life. Like other epiphytic diseases, want of personal cleanliness has a great deal to do with the prevalence of pinta in the districts mentioned, for it is rare in cleanly whites or well-to-do negroes; the dirty Indians and the poor half-castes are those most frequently affected. In some districts it occurs in nearly a tenth part of the inhabitants, in others nearly the entire population is affected. Lately a somewhat similar disease