largely based upon Paul of Aegina's Pragmateia, the writings of Abulcasis (Abu al-Qasim Khalaf ibn al-Abbas Al-Zahrawi), an Andalusian-Arab physician and scientist who practiced in the Zahra suburb of Córdoba, were influential. Al-Zahrawi specialized in curing disease by cauterization. He invented several surgical instruments for purposes such as inspection of the interior of the urethra and for removing foreign bodies from the throat, the ear, and other body organs. He was also the first to illustrate the various cannulae and to treat warts with an iron tube and caustic metal as a boring instrument. He describes what is thought to be the first attempt at reduction mammaplasty for the management of gynaecomastia and the first mastectomy to treat breast cancer. He is credited with the performance of the first thyroidectomy. Al-Zahrawi pioneered techniques of neurosurgery and neurological diagnosis, treating head injuries, skull fractures, spinal injuries, hydrocephalus, subdural effusions and headache. The first clinical description of an operative procedure for hydrocephalus was given by Al-Zahrawi, who clearly describes the evacuation of superficial intracranial fluid in hydrocephalic children. Early modern Europe In Europe, the demand grew for surgeons to formally study for many years before practicing; universities such as Montpellier, Padua and Bologna were particularly renowned. In the 12th century, Rogerius Salernitanus composed his Chirurgia, laying the foundation for modern Western surgical manuals. Barber-surgeons generally had a bad reputation that was not to improve until the development of academic surgery as a specialty of medicine, rather than an accessory field. Basic surgical principles for asepsis etc., are known as Halsteads principles. There were some important advances to the art of surgery during this period. The professor of anatomy at the University of Padua, Andreas Vesalius, was a pivotal figure in the Renaissance transition from classical medicine and anatomy based on the works of Galen, to an empirical approach of 'hands-on' dissection. In his anatomic treaties De humani corporis fabrica, he exposed the many anatomical errors in Galen and advocated that all surgeons should train by engaging in practical dissections themselves. The second figure of importance in this era was Ambroise Paré (sometimes spelled "Ambrose"), a French army surgeon from the 1530s until his death in 1590. The practice for cauterizing gunshot wounds on the battlefield had been to use boiling oil; an extremely dangerous and painful procedure. Paré began to employ a less irritating emollient, made of egg yolk, rose oil and