In the Latin translation of Avicenna by Bullonensis, alphos albus and niger are distinguished by the names of _morphea alba_ (or _alguada_), and _morphea nigra_; leuce by that of _albaras_; and lepra by those of _albaras_ nigra and _impetigo excorticativa_. The specific differences between them are stated with great precision. The morpheæ are superficial affections of the skin, but the albaras affects also the flesh, penetrating sometimes down to the bone. All these diseases are said to arise from a weakness of the assimilative faculty. In the _albaras_ nigra, or leprosy, the skin is said to be covered with scales, like those of a fish. Like the authorities formerly quoted, Avicenna states that in _alguada_ (alphos albus) the hairs do not change their colour, but that they do so in _albaras_. The puncture of a needle likewise extracts blood from the _guada_, but not from the _baras_. Avenzoar makes mention of the _morphea_ alba and nigra, but has not described them particularly. These authors seem to have treated lepra and psora like the Greeks, by bleeding, melanogogues, and abstergent applications to the skin, such as the two hellebores, lime, lupines, &c. In the translation of Haly Abbas, leuce is correctly described by the name of _lepra_. It is represented as a whiteness sometimes affecting the whole body, and it is said to be occasioned by debility of the assimilative faculty. When the hairs are white, and the skin does not bleed when pricked with a lancet or needle, the disease is incurable. Alphos albus is described by the name of _morphea_ alba, and is distinguished from the former by the whiteness being more superficial, and the colour of the hairs remaining unchanged. In the morphea nigra, that is to say the alphos niger, the colour is said to be black, owing to the prevalence of black bile, and if rubbed a furfuraceous scale falls off, and it becomes red. The lepra nigricans is described by the names of _impetigo_ and _sarpedo_, as an asperity of the skin, inclining to blackness or redness, and terminating in round scales, like those of fishes. For the cure of lepra, he directs us to abstain from all articles of food which engender phlegm, to take hiera of colocynth, with pepper, &c., and also the theriac of vipers, and various other internal medicines. He recommends various external applications, containing sulphur, arsenic, hellebore, spurge, &c.