FAVUS, a disease of the scalp, but occurring occasionally on any part of the skin, and even at times on mucous membranes. The uncomplicated appearance is that of a number of yellowish, circular, cup-shaped crusts grouped in patches like a piece of honeycomb, each about the size of a split pea, with a hair pro jecting in the centre. These increase in size and become crusted over, so that the characteristic lesion can only be seen round the edge of the scab. Growth continues to take place for several months, when the scab comes away, leaving a shining bare patch destitute of hair. The disease is essentially chronic, lasting from Jo to 20 years. It is caused by the growth of a fungus (Acliorion Sclionleinii) and was the first disease in which a fungus was dis covered—by J. L. Schonlein in Since then other varieties of the fungus have been described. Favus is commonest among the poorer Jews of Russia, Poland, Hungary, Galicia and the East, and among the same class of Mohammedans in Turkey, Asia Minor, Syria, Persia, Egypt, Algiers, etc. It is not rare in the southern departments of France, in some parts of Italy, and in Scotland. It is spread by contagion, usually from cats, often, however, from mice, fowls, or dogs. Before treatment can be begun the scabs must be removed by means of carbolized oil, and the head thoroughly cleansed with soft soap. The cure is then brought about by the judicious use of parasiticides.