The extraction of a tooth is only justifiable, says Gaddesden, when all the remedies employed against odontalgia have proved useless and when, on the other hand, the pain has its seat in the tooth itself and not in the nerves or gums. Before undertaking the operation, however, the patient must be prepared for it with an evacuant cure, that is, by injections and purgatives. For the operation itself the author recommends the same rules given by Celsus, and says, besides, that the head of the patient ought to be held firm by an assistant. In certain cases, the extraction can be performed, better than with the forceps, by means of an instrument in the form of a lever, broad at one end, narrow and sharpened at the other. But when a tooth is very firmly seated, its extraction is always dangerous; therefore, in such a case, Gaddesden recommends, before having recourse to the operation, the use either of acrid substances, such as the milky juice of the euphorbiaceæ (for example, of the tithymal), or else of a red-hot iron; and this, for the purpose of promoting the fall of the tooth, or of rendering it, at least, so far movable that it can be extracted without any difficulty. GUY DE CHAULIAC, the greatest surgeon of the middle ages, was born about 1300, in a little village on the confines of Auvergne, which still preserves the name of Chaulhac; he died in 1368. This author immortalized his name by a work which even up to the eighteenth century was, as it were, the official code for the teaching of surgery. Guy wrote his _Chirurgia magna_ in barbarous Latin—such as was then used by the learned; but his book was soon translated into French, Provençal, and afterward also into Italian, English, Dutch, and Hebrew. E. Nicaise, who, in 1890, gave to the scientific world a very valuable new edition of Guy de Chauliac,[231] and who made very accurate researches on all that regards this author and his work, has succeeded in finding in the libraries of Europe and America as many as thirty-four manuscript copies of the _High Surger_.[232] The survival of so many copies, in spite of all the destructive agencies which have been in action during more than 500 years, is a very clear proof of the wide diffusion which this work obtained even before the invention of printing. Guy’s work was printed for the first time in 1478, and the editions that have been published since then in various countries are in all about 130. This book is very important for our subject, since we may gather from it very clearly the condition of dentistry in the fourteenth century; but, on the other hand, we see from it, with equal clearness, that this branch of the healing art had not made any progress from the time of Abulcasis to that of Guy de Chauliac (about two centuries and one-half), and that this most famous surgeon did not contribute anything worthy of note to the development of dentistry.