“Sometimes on the surface of the teeth, both inside and outside, as well as under the gums, are deposited rough scales, of ugly appearance, and black, green, or yellow in color; thus corruption is communicated to the gums, and so the teeth are in process of time denuded. It is necessary for thee to lay the patient’s head upon thy lap and to scrape the teeth and molars, on which are observed either true incrustations, or something similar to sand, and this until nothing more remains of such substances, and until also the dirty color of the teeth disappears, be it black, or green, or yellowish, or of any other color. If a first scraping is sufficient, so much the better; if not, thou shalt repeat it on the following day, or even on the third or fourth day, until the desired purpose is obtained. Thou must know, however, that the teeth need scrapers of various shapes and figures, on account of the very nature of this operation. In fact, the scalpel with which the teeth must be scraped on the inside is unlike that with which thou shalt scrape the outside; and that with which thou shalt scrape the interstices between the teeth shall likewise have another shape. Therefore, thou must have all this series of scalpels ready if so it pleases God.”[212] The work of Abulcasis is, so far as we know, the first book in which are found figures of dental instruments. We do not know, however, how far such figures are exact, that is, to what degree of faithfulness they represent the instruments which Abulcasis really employed as the original figures of the book of Abulcasis were copied and recopied by successive transcribers of the work. And that such copies have been very often unfaithful may be deduced from the fact that not unfrequently figures of surgical instruments are found in the book which do not at all agree with the verbal description which the author gives of such instruments. In the edition by John Channing, we find at the end of the chapter on the scraping of the teeth two series of figures. The first series is found under the Arabic text, and is composed of the fourteen figures reproduced as Fig. 35; the other series, existing under the Latin text, has only twelve figures, as shown in Fig. 36.