The 7th and 8th books of the _De re Medicina_ relate entirely to surgery; this is of course Greek, which in its turn was probably of Egyptian and Indian origin. He describes operations such as we now call “plastic,” for restoring lost or defective portions of the nose, lips, and ears. These are constantly claimed as triumphs of modern surgery, and have been asserted to have been successful as the result of information derived from experiments on living animals. His description of lithotomy is that which was anciently practised in Alexandria, and was doubtless derived from India. Trephining the skull is described, and this again is proved not to have been invented in modern times, as some have thought. Even subcutaneous urethrotomy was a practice followed in the time of Celsus. We have also the first detailed description of the amputation of an extremity. Many ophthalmic operations are described according to the methods followed by the eye specialists of Alexandria.[466] In his eight books on medicine the first four deal with internal complaints, such as usually yield to careful dieting. The fifth and sixth are concerned with external disorders, and contain many prescriptions for their treatment. The seventh and eighth, as we have seen, are exclusively surgical. Celsus followed principally Hippocrates and Asclepiades as his authorities. He transfers many passages from the Father of Medicine word for word. His favourite author was Asclepiades, and it is for that reason that he is held to be of the Methodical school of medicine. He was no believer in the mysterious numbers of the Pythagorean, and was evidently quite free from slavish devotion, even to his great authorities in medicine. He recommends that dislocations should be reduced before inflammation sets in. When fractures fail to unite, he recommends extension and rubbing together of the ends of the bone. He goes so far as to advise cutting down to the bone, and letting the fracture and wound heal together. He cautions against the use of purgatives in strangulated hernia, and gives directions for extracting foreign bodies from the ears.