Fauchard gives an excellent description of the alveoli and of the roots of the teeth; he alludes to the varieties which these latter may present, and to the importance of the same from the point of view of extraction. Thus, speaking of the molars, he says: “Their roots sometimes touch one another at the points, whilst at the base, close to the body of the tooth, they are far apart. These are the so-called _dents barrées_ (barred teeth), which it is so difficult to extract, it being unavoidable to bring away together with the tooth the spongy osseous part occupying the interval between the roots.” In this same chapter the author calls our attention to some anomalies worthy of note. He says that he has observed teeth that seemed to him to be derived from the union of two or three germs. He also relates that a colleague of his showed him a tooth that appeared to be formed by the union of two, between the roots of which was a third tooth whose crown was united to the vault formed by the roots of the first two. Fauchard describes exactly the pulp cavity and the root canals, and speaks of their gradual restriction, ending in an almost entire disappearance in old age.[412] He treats of the nerves, of the arteries, and of the veins of the teeth in a most detailed manner; then, after alluding to their general structure, he goes on to speak of the microscopic constitution of the enamel, following in this the description given of it in 1699 by the academician La Hire. In regard to the development of the teeth, Fauchard repeats what Urbain Hémard had previously written. He apparently ignores the researches of the Italian anatomists, from whom, and especially from Eustachius, Urbain Hémard had literally reproduced all that concerns odontogeny. In the second chapter Fauchard speaks “of the maladies of children at the period of teething and of the remedies best adapted thereto.” Among other means of treatment, he advises the incision of the gum when this is red, swollen, and distended and the tooth below it can be felt. For the incisors and canines a simple incision ought to be made in the same curve as the dental arch; for the molars a crosswise incision should be made directly down to the tooth below, taking care not to leave any strips of uncut gingival tissue, lest these, being distended by the emerging tooth, should continue to be the cause of pain and other morbid phenomena. Although Fauchard does not tell us anything substantially new about teething maladies and their treatment, he nevertheless treats this subject with much practical good sense, and does not merely make servile repetition of what preceding authors have written about it. In the three following chapters the author speaks of the utility of the teeth, of the rules to be observed for their preservation, of the modes of keeping them white, and of strengthening the gums.