From the fact of the _odontagogon_ in the temple of Apollo being made of lead, Erasistratus, Celius Aurelianus, and other ancient writers have drawn the deduction that it was only permissible to extract teeth when they were loose enough to be taken out with a leaden instrument. But Serre[44] observes, not without reason, that if a tooth be so unsteady as to be able to be extracted with leaden pincers, this may just as well be done, and perhaps even better, by pinching the tooth between the fingers, no other aid being required than a handkerchief to prevent them from slipping. Avulsive pincers of lead would be, therefore, a nearly useless invention; so it is much more probable, as Serre remarks, that the original pincers were of iron, and that the inventor, reserving these for his own use, made a simple model of the same in lead (this being easier to do) and deposited it in the temple of Apollo, in order to make known the form of the instrument to contemporaries and to posterity, naturally supposing that whoever wished to copy it would understand of himself, or learn from the priests, that it was to be made of iron and not of lead. [Illustration: FIG. 7 Portrayal of a dental operation on a vase of Phœnician origin, found in Crimea (see Cigrand, Rise, Fall, and Revival of Dental Prosthesis, pp. 60-63 and 287).] HIPPOCRATES. The sacerdotal and philosophical schools of medicine, as well as the gymnasiums, were the three great sources whence Hippocrates derived his first knowledge of medicine. Hippocrates was born in the island of Cos, toward the year 460 B.C. He belonged to the sacerdotal caste of the Asklepiadi, and was, according to some of his earliest biographers, the nineteenth descendant of Æsculapius on his father’s side, and the twentieth descendant of Hercules on his mother’s side. The time of his death is even still more uncertain than that of his birth, for, according to some, he died at eighty-three, according to others, at eighty-five, at ninety, at one hundred and four, and even at one hundred and nine years of age.