About this period, in a distant corner of the Greek empire - at the medical school in Alexandria, Egypt, the human body was purposefully dissected in order to reveal its internal structure. Here, Herophilus (c.300B.C. - ) and Erasistratus (c.250B.C. - ) made many anatomical discoveries through routine dissection of more than 600 cadavers, and allegedly condemned criminals. The Roman scholar Celsus (c.30 B.C. 45 A.D.) wrote that the criminals were obtained “for dissection alive, and contemplated, even while they breathed, those parts which nature had before concealed.” According to the historian Tertullian as many as 600 living criminals were vivisected, and even fetuses were removed from the womb. He described Herophilus as “that butcher who cut up innumerable corpses in order to investigate nature and who hated mankind for the sake of knowledge.” Herophilus is often called the “father of anatomy.” All of his writings, including his book “On Anatomy” has been destroyed. Herophilus described the delicate arachnoid membranes of the cerebral ventricles, the confluence of venous sinuses near the internal occipital protuberance which bears his name, the lacteals, coverings of the eye, liver, uterus, epididymis, and many other structures. The name “duodenum” is attributed to him. Herophilus differentiated nerves of sensation from those associated with voluntary movement, and he knew that damage of the latter led to paralysis. The younger Erasistratus was more a physiologist. He formulated a “pneumatic theory” and regarded the heart as a pump. Erasistratus described the auricles of the heart, cardiac valves, blood vessels, including the aorta, pulmonary artery and veins, hepatic arteries and veins, renal vessels, superior and inferior vena cava, and the azygous vein. Erasistratus recognized the function of the trachea. He also differentiated the cerebrum from the cerebellum, described the cerebral convolutions, ventricles, and meninges. Alexandria began its decline with the Roman invasion in 48 B.C., climaxed by the burning of its famous library of 700,000 volumes. At that time the library housed all the learning of the ancient World. Egypt became part of the Roman empire, and medicine was still nurtured by Greek and other scholars but culturally in a Roman environment. Human dissection was forbidden or not encouraged - a situation that lasted until the late middle ages. Like in some medical schools today, it was declared unnecessary in the training of physicians. The greatest figure of the time was the physician Claudius Galen (AD131 - 201).