We call that disorder a porrigo, _scurf_, when certain small scales arise amongst the hair, and are loosened from the skin; they are sometimes moist, much more frequently dry. It happens sometimes without any ulcer, sometimes in a part that is ulcerated, and is sometimes attended with a bad smell, sometimes with none. It usually occurs in the hair of the head, more rarely in the beard, sometimes also in the eye-brows. And as it never comes without some antecedent disorder in the body, so it is not altogether useless. For when the head is free from disorders, then it does not appear: when there is any disorder there, it is more expedient, _in such a case_, that the surface of the skin should be here and there corrupted, than that the noxious matter should be turned in upon a more noble part. It is more proper then to cleanse it by frequent combing, than to repel it entirely. But if that method makes it more offensive (which may happen by the excessive discharge of humour, and more so, if the humour be fetid) the head is to be shaved often; and treated with some gentle repellents, such as nitre with vinegar, or labdanum with myrtle oil, and wine, or myrobalans with wine. If these have little effect, we may use some of the more powerful ones; but, at the same time, we should be aware, that this practice is hurtful, when the disorder is recent. CHAP. III. OF THE SYCOSIS. There is an ulcer, which from its resemblance to a fig, by the Greeks, is called sycosis[FQ], because flesh sprouts up from it. And this is the general name. Under it are included two species. The one is a hard and round ulcer; the other is moist and unequal in its surface. From the hard one the discharge is very small and glutinous; from the moist, it is in greater quantity and fetid. Both kinds occur in the parts covered with hair: but that which is callous and round, most frequently in the beard; the other, which is moist, chiefly in the hair of the head. [FQ] σύκωσις. To both of them it is proper to apply elaterium, or lintseed powdered, and made into a paste with water, or a fig boiled in water, or the tetrapharmacum plaister softened with vinegar. Eretrian earth also liquified with vinegar is proper to lay upon them. CHAP. IV. OF AREAE.