GEORG HEURMANN, a surgeon in Copenhagen, recommends making use, after the Cowper-Drake operation, of a small cannula in order to facilitate the exit of the pathological material contained in the sinus, and also to render it easier to introduce into it medicated or detersive substances.[479] LÉCLUSE. One of the most celebrated French dentists of the eighteenth century is Lécluse. Dental literature was enriched by him with several works, partly written in popular style, partly addressed to dental specialists. In 1750 he published his _Traité utile au public, où l’on enseigne la méthode de remédier aux douleurs et aux accidents qui précèdent et qui accompagnent la sortie des premières dents, de procurer un arrangement aux secondes, enfin de les entretenir et de les conserver pendant le cours de la vie_. The work seems to have been very favorably received, as its first edition, printed in Nancy, was followed by a second, printed in Paris, only four years later. In 1755 he published another book: _Eclaircissements essentiels pour parvenir à préserver les dents de la carie et le conserver jusqu’à l’extrème vieillesse_. But the most important of his works is the _Nouveaux éléments d’odontologie_,[480] the first edition of which was published in 1754, and followed by a second in 1782. We do not enter into a minute examination of these works, which, taken altogether, do not contain anything very new. We will only remark that Lécluse treated in a succinct but correct manner the anatomy of the mouth; invented some and perfected other instruments, the most important of which is the elevator that still bears his name, and finally, that he frequently performed the operation of replantation, warmly recommended by him as an excellent means of cure in certain cases of caries. The extracted tooth was stopped and afterward replanted, and, says Lécluse, became fast within eight days, proving as serviceable as a perfectly healthy tooth, and never again causing any pain. PHILIP PFAFF, dentist to Frederick the Great, King of Prussia, was the first among the Germans who wrote a real treatise on dentistry. His book[481] contains, in 184 succinctly but well-written pages, the anatomical and physiological notions relative to the teeth, as well as all that belongs to dental pathology, therapy, and prosthesis. Besides a few observations about supernumerary teeth, Pfaff relates several cases in which the incisors, inferior as well as superior, were renewed (twice consecutively), that is, once at the usual epoch, and the second time between the seventh and thirteenth years. He also cites from the anatomical tables of Kulmus the following epitaph in low Latin, that seems to allude to a case of third dentition: “Decanus in Kirchberg, sine dente canus, ut anus Interum dentescit, ter juvenescit, his requiescit.”