The eruption consists of roundish or oval patches, not elevated or only very slightly so, several of them occasionally coalescing to form large patches of irregular outline. The colour is pinkish, or reddish-pink, occasionally coppery with a fawnish tinge ; there are no scales, the surface is smooth and tense, rather shiny, or very finely wrinkled. As a rule, there is no desquamation ; there is also no pruritis, or, if any, it is very slight. The superficial lymphatic glands are not enlarged. The blood does not show — at least in the cases I have examined^^-any abnormality. The general health is in no way impaired.
The Fungus. — If one of the reddish patches is scraped and a preparation examined in Liq. potassae, the fungus can be easily detected. It consists of mycelium and spores, the general characters being those of a Malassezia. The mycelium closely resembles that found in Pityriasis flava and in the pityriasis of temperate zones; but the spores have more resemblance to the spores of Tinea mansoni. The mycelial threads are rather thick and often show swellings, constrictions, and other irregularities of shape. The free spores are globular, of rather large dimensions, 4 to ti microns. They are often collected in clusters. I have not, so far, succeeded in growing the fungus.
Diagnosis. — The condition with which the disease is most easily confounded is a form of Seborrhcea corporis, localised on the chest, very frequent in hot climates. In fact, two of the patients sent to me were thought to be suffering from Seborrhcea corporis, and without the help of the microscope I should have made the same diagnosis. The microscopical examination will also distinguish the disease from the Pityriasis rosea of Gilbert.
Ringworm. — In contrast to ringworm, T. rosea is practi- cally non-pruriginous; it does not develop in circles, and the margins of the patches are not sensibly elevated.
Syphilis, — On superficial examination the eruption,
