The author then speaks of cases where it is necessary to open the jaws by force;[431] of the instruments to be used; of the mode of employing them; of all the precautions to be observed under such circumstances; of the necessity that may eventually arise of sacrificing some one tooth when the enforced opening of the jaws has been impracticable; of the advisability of sacrificing preferably in such cases one of the premolars in order to damage as little as possible the masticatory function and the appearance of the face; of the instruments best adapted for carrying out this operation; of the danger it presents and of the best mode of avoiding it; finally, of what it is necessary to do in given cases to keep the mouth open, in order to not be obliged to repeat the operation a second time. The six following chapters of the first volume treat very extensively of the anatomy and physiology of the gums,[432] of gingival diseases and their treatment.[433] The subject is treated in a masterly manner, although these chapters do not offer anything of original importance. The same may be said of Chapter XXII, in which the author speaks of scorbutic affections and of their treatment. The chapters we have cited are accompanied by four plates, representing thirteen instruments for use in the treatment of the above diseases. [Illustration: FIG. 78 Instruments for opening the mouth in cases of lockjaw (Fauchard).] The author then speaks[434] of the accidents which may arise from caries and from other dental diseases, not only in the parts nearest to the teeth, but also in localities more or less distant from them, for example, fistulæ reaching as far as the cheek bone or the eye, necrotic destruction of the maxillary bones, etc. The first volume of Fauchard’s work finishes with a collection of most interesting cases, which may be read even at the present day with pleasure, and from which one may derive some useful information. These cases are about eighty in number, spread over fifteen chapters, according to the various nature of the cases themselves. This valuable collection gives clear evidence of Fauchard’s eminence both as operator and observer, and affords at the same time an idea of the extent of his practice which enabled him to collect so considerable a number of cases of more than common interest. Chapter XXV contains some observations on “_well-authenticated cases_” of regeneration of permanent teeth in individuals of ages varying from fifteen to seventy-five years. We will here give two of them by way of curiosities: “In the year 1708 Mademoiselle Deshayes, now the wife of M. de Sève, residing at Paris in rue de Baune, and who was then fourteen years of age, had the first large molar on the right side of the inferior jaw extracted by me, because decayed and causing pain. The following year she returned to have her teeth cleaned by me, and whilst doing this I observed that the tooth extracted had been wholly regenerated.”[435]