pros and cons of both animal experimentation and human experimentation. Celsus discusses, for example, the case of Herophilos and Erasistratos, who he asserts practised vivisection. In the treatment of disease, Celsus's principal method was to observe and watch over the operations of Nature, and to regulate rather than oppose them, conceiving that fever consisted essentially in an effort of the body to throw off some morbid cause, and that, if not unduly interfered with, the process would terminate in a state of health. On occasions, however, he boldly recommends the use of the scalpel; his rules for blood letting and purgatives are laid down with detail and precision; and many of the rules he prescribes were not very different from those still in use at the beginning of the 19th century. His work contains detailed descriptions of the symptoms and different varieties of fever, and he is credited with recording the cardinal signs of inflammation known as "Celsus tetrad of inflammation": calor (warmth), dolor (pain), tumor (swelling) and rubor (redness and hyperaemia). He goes into great detail regarding the preparation of numerous ancient medicinal remedies including the preparation of opioids. In addition, he describes many 1st century Roman surgical procedures which included removal of a cataract, treatment for bladder stones, and the setting of fractures. Celsus wrote on the anatomy of the eye and was the first to call one of its layers the choroid. During the twentieth century, many historians claimed that Celsus believed that the crystalline lens is in the exact center of the eye. In fact, Celsus made no specific statement about the position of the crystalline lens, and his Graeco-Roman contemporaries did understand that the lens is located to the front. Hippocrates used the Greek word καρκίνος, karkínos 'crab, crayfish' to refer to malignant tumors as carcinomas. It was Celsus who translated the Greek term into the Latin cancer, also meaning 'crab'. The first printed edition of Celsus' work was published in 1478. His style has been much admired as being equal in purity and elegance to that of the best writers of the Augustan age. Some online editions In hoc volvmine haec continentvr Avrelii Cornelii Celsi medicinae libri VIII : qvam emendatissimi, Graecis etiam omnibvs dictionibvs restitvtis. Beigefügte Werke: Qvinti Sereni Liber de medicina et ipse castigatiss. Accedit index in Celsvm et Serenvm sane qvam copiosvs ... [Hrsg.: Ioannes Baptista Egnatius]. Venetiis : in aedibvs