A. CORNELIUS CELSUS, who flourished between B.C. 50 and A.D. 7, was a celebrated patrician Roman writer on medicine, and an encyclopædic compiler of a very high order. It is disputed whether he was or was not a physician in actual practice; probably he was not. He practised certainly, but on his friends and servants, and not professionally. The medical practice of the period was for the most part in the hands of the Greeks. We owe little to the Romans that was original or important in connection with the healing art, yet in Celsus we have an elegant and accomplished historian of the medical art as it was practised in ancient Rome; he wrote not so much for doctors as for the instruction of the world at large. His works were not studied by medical men, at any rate, as anything more than mere literature. No medical writer of the old world quotes Celsus. Pliny merely refers to him as an author. Very probably he merely compiled his treatises, of which the most celebrated is his _De Medicina_, in the introductions to the 4th and 8th books of which there is evidence of his considerable knowledge of anatomy. He seems to have understood the anatomy of the chest and the situation of the greater viscera especially well, though of course in this respect falling far short of our present knowledge of the science, and not in every case fully up to that of the Greeks. His knowledge of surgery was considerable, especially that of the pelvic organs of the female. In osteology, or the science of the bones, he excelled. He accurately describes the bones of the skull, their sutures, and the teeth. His descriptions of the vertebræ and ribs, the bones of the pelvis and the upper and lower extremities, are accurate and careful. He understood the articulations, and is careful to emphasize the fact that cartilage is always found in their formation. He must have been acquainted with the perforated plate of the ethmoid bone, as he speaks of the many minute holes in the recess of the nasal cavities, and it is even inferred by Portal that he knew the semicircular canals.[465]