known to the Chinese some thousands of years ago, and the name they gave it, Tchong-kiai, which means pustules formed by a worm, indicates that at least when that term was adopted they had some acquaintance with the character of the disease.
Some writers have supposed that certain of the uncleannesses alluded to in the Book of Leviticus have reference to this complaint; and it is quite possible that in old times it acquired a much more severe character than it ever has now, owing to neglect or improper treatment. Psora, in Greek, and the equivalent term Scabies, in Latin, are supposed to have at least included the itch, though in all probability those words comprehended a number of skin diseases which are now more exactly distinguished. Hippocrates mentions psora, and apparently treated it solely by the internal administration of diluents and purgatives. Aristotle mentions not only the disease but the insects found, he said, in the blisters. Celsus advocated the application of ointments composed of a miscellaneous lot of drugs, such as verdigris, myrrh, nitre, white lead, and sulphur. Galen hints at the danger of external applications which might drive the disease inwards. In Cicero, Horace, Juvenal, and other of the classical writers, the word scabies is used to indicate something unnatural; showing that it had come to be adopted metaphorically.
The Arab writers are much more explicit. Rhazes, Haly Abbas, and Avicenna are very definite in their descriptions of the nature of the complaint, and how it is transmitted from one person to another; but Avicenna's mode of treatment was directed to the expulsion of the supposed vicious humours from the body by bleeding and purgatives, especially by a
