As to extraction, Fabricius of Aquapendente counsels great prudence in performing the operation, and on this point he repeats all the warnings already given by Celsus, an author whom he greatly admires and the study of whose writings he warmly recommends. It seems that in those times there was more than sufficient reason to inculcate extreme caution in regard to the extraction of teeth. This was not then performed by true dentists, but rather by barbers and by ignorant tooth-pullers, or else, in exceptional cases, by general surgeons, very skilful, perhaps, in everything else, but little practised in the operation we are speaking of; besides this, the instruments left much to be desired; and lastly there was not, nor could there be, any idea of asepsis. What wonder, therefore, if the extraction of teeth was frequently the cause of serious injuries! Fabricius relates that it often happened to him to have to extract, in little fragments, half or sometimes a whole jaw, which had been attacked by putrefaction, as the result of the extraction of one single tooth. This, adds the author, may easily happen, because, when the jaw is attacked by pus in one point, its very anatomical constitution favors the rapid spreading of the putrefying process to the other parts of the bone, as this latter, apart from its external lamina, is entirely composed of a sponge-like substance. The instruments which are used for the extraction of teeth, are, says Fabricius, of nine kinds;[323] and the most important among them—generically called _forceps_—are indicated by special names, taken from their resemblance to the mouth or beak of certain animals. Thus, the forceps with which it is usual to perform the extraction of molar teeth are called “pelicans,” and of these there are two kinds, according as they are used for the right or the left side, for the upper molars or the lower ones. A third kind of instrument goes under the name of “beak” (rostrum), and serves for the extraction of the incisors. A fourth kind is the “crow’s beak,” or “crow’s bill,” which is used for the extraction of roots. Two other instruments are named in Italian “cagnoli,” for they imitate the strong bite of the dog (in Italian _cane_) and are used in cases where the pelican is not adapted. A seventh instrument is called by the Latin term of _terebra_ (drill or auger). It is used instead of a lever to separate the teeth from one another when they are too close to each other, and so render their extraction much easier. The eighth instrument is a “trifid lever” (_vectis trifidus_), so called because it is furnished with three points. The ninth and last kind of instruments are the _dentiscalpia_, slender, sharp, and oblong tools, with which the gums are separated from the teeth before extraction.