It is evident from the books left by Avenzoar, whose full name was Abdel-Malek-Abou-Merwan-Ebn-Zohr, that in his time the practices of medicine, surgery, and pharmacy were quite distinct in Spain, and he apologises to the higher branch of the profession for his interest in those practices which were usually left to their servants. But he states that from his youth he took delight in studying how to make syrups and electuaries, and a strong desire to know the operation of medicines and how to combine them and to extract their virtues. He writes about poisons and antidotes; has a chapter on the oil alquimesci, which Freind renders oil of eggs, and Sprengel calls oil of dates. Avenzoar says his father brought it from the East, and that it was a marvellous lithontryptic. He tells how mastic corrects scammony, and sweet almonds colocynth. He is the earliest writer to refer to the medicinal virtues of the bezoar stones. He gives a different account of the origin of these stones from that of other authors. The best, he says, comes from the East and is got from the eyes of stags. The stags eat serpents to make them strong, and at once to prevent any injury their instinct impels them to run into streams and stand in the water up to their necks. They do not drink any water. If they did they would die immediately; but standing in the stream gradually reduces the force of the poison, and then a liquor exudes by the eyelids which coagulates and forms a stone which may grow to the size of a chestnut, which ultimately falls off. According to another Arab author, Abdalanarack, the bezoar stone acquired such a celebrity in Spain that a palace in Cordova was given in exchange for one.