In Aristotle’s _Mechanics_, the following question relative to the extraction of the teeth is discussed: “Why do doctors extract teeth more easily by adding the weight of the odontagra (dental forceps) than by using the hand only? Can it be said that this occurs because the tooth escapes from the hand more easily than from the forceps? Ought not the irons to slip off the tooth more easily than the fingers, whose tips being soft can be applied around about the tooth much better? The dental forceps,” adds Aristotle, “is formed by two levers, acting in contrary sense and having a single fulcrum represented by the commissure of the instrument. By means of this double lever it is much easier to move the tooth, but after having moved it, it is easier to extract it with the hand than with the instrument.” From this passage of Aristotle one may draw various conclusions. First of all, it appears that, at that time, the extraction of teeth was a common enough operation carried out by doctors in general, or, at least, by specialists not indicated by any particular denomination but called doctors (in Greek, ιατροι) just the same as those who dealt with the maladies of every other part of the body. If, therefore (which, however, is very doubtful), there existed in Greece, as there certainly did in Egypt, individuals who occupied themselves _exclusively_ with the treatment of the teeth, they cannot have formed a distinct class of professionals, but merely a section of the medical class. Herodotus, too, as we have already seen, does not say, speaking of Egypt, that there was a proper class of dentists, but gives us to understand that the Egyptian doctors did not occupy themselves indiscriminately with the treatment of all maladies, for some dedicated themselves to curing the eyes, others to the treatment of maladies of the head, others to those of the teeth, and so on. From the Aristotelian passage on the extraction of teeth, just quoted, it may be concluded that in those times the Hippocratic precept, that only loose teeth were to be extracted, was not observed, for otherwise, Aristotle could not have said that dental forceps are useful to loosen the teeth, but that after this has been done the extraction of the tooth may be more easily effected by means of the fingers than with the instrument. This last assertion appears very strange. It demonstrates that either the instruments then in use were very imperfect, or that Aristotle, although the son of a doctor and himself possessed of vast medical knowledge, had absolutely no experience as to the extraction of teeth; and, therefore, speaking theoretically, and without any practical basis, he ran into error, as even the greatest men are apt to do when drawing conclusions from purely theoretical reasonings.