Treatise of hygiene and medicine, in French and Latin, interpretation of the urine, 15th Century. The uroscopy wheel is a diagram that linked the color of urine to a particular disease. It usually has twenty different uroscopy flasks with urine of different colors aligned around the border of the circle. Each flask has a line that connects it to a summary of a particular disease. This allowed doctors to have a quick reference guide to twenty different types of urine. Uroscopy is the historic medical practice of visually examining a patient's urine for pus, blood, or other symptoms of disease. It dates back to ancient Egypt, Babylon, and India. It was particularly emphasized in Byzantine medicine. By modern medical standards, uroscopy is considered to be a very limited means of obtaining evidence for the correct diagnosis of a patient's condition. In addition, many of the assumptions made by ancient physicians regarding uroscopy have proved to be quite incorrect and unscientific.