Several contributions to the knowledge of the diseases of the maxillary sinus and their treatment were made about this time by Beaupréau, Dubertrand, Caumont, Dupont, Chastanet, Doublet, David, and especially by Thomas Bordenave, who published an important work on this subject, collecting a great number of clinical cases of great interest. Speaking of the Cowper-Drake operation, he expresses the opinion that the tooth to be extracted is not the same in all cases, for if some one of the teeth situated below the maxillary sinus should either show signs of decay or be the seat of persistent pain, the choice should fall upon that one. If, however, these teeth are all apparently sound, the one should be chosen that, under percussion, is most sensible to pain. In those cases in which the choice is altogether free, Bordenave prefers the extraction of the first large molar, for the double reason that it is generally situated in correspondence to the central part of the cavity, and that it is separated from the antrum by a very thin osseous lamina. In certain cases, the maxillary sinus is divided, by body lamellæ, into various cavities, and then, as one easily understands, it may be necessary to extract more than one tooth for the evacuation of the pathological contents. When the teeth situated below the antrum have fallen out, or have been extracted some time, and their alveoli are in consequence obliterated, it will be better to have recourse to Lamorier’s method. This method may besides be useful, according to Bordenave, either when all the teeth are sound and it would consequently be a pity to sacrifice any of them, or in special cases (such as large polypi of Highmore’s antrum, extraneous bodies, etc.) in which the Cowper-Drake operation would not afford sufficient space. L. B. LENTIN, a German, in 1756, published a pamphlet[494] in which he recommended electricity as a means of cure for toothache. Other writers recommended the use of the magnet, which means of cure had already been advised for various affections by Patacelus. During the latter half of the seventeenth century, Talbot, J. J. Weckes, and P. Borelli related several cures of headache and toothache by the use of the magnet. In the eighteenth century F. W. Klaerich, a medical man in Göttingen, wrote that he had used the magnet advantageously in not less than 130 cases of toothache.[495] We find it recommended later by others, Brunner, and particularly J. G. Teske, who, in 1765, wrote a pamphlet entitled _New experiments for the curing of toothache by means of magnetic steel_.[496] He considers the use of the magnet as the most efficacious of all remedies against toothache, and believes its action to be similar to that of electricity.