He said in a very important text :
'' the physician asks the patient about the cause of his illness and the pain he feels. He prepares for the patient syrups and other drugs, then he writes a copy of the prescription to the parents attending with the patient. Next day he re-examines the patient and looks at the drugs and asks him if he feels better or not, and he advises the patient according to his condition. This procedure is repeated on the third day and the fourth... till the patient is either cured or dead. If the patient is cured, the physician is paid. If the patient dies, his parents go to the chief doctor, they present the prescriptions written by the physician. If the chief doctor judges that the physician has performed his job perfectly without negligence, he tells the parents that death was natural; if he judges otherwise, he tells them: take the blood money of your relative from the physician; he killed him by his bad performance and negligence. In this honorable way they were sure that medicine is practiced by experienced well trained persons '' (12).