Herophilus was a Greek physician. He was born in Chalcedon (now Kadiköy, Turkey) in 335 B.C. and died in 280 B.C. He is known as the father of anatomy because he was the first to base his conclusions on dissection of the human body. He studied the brain, recognizing it as the center of the nervous system. He distinguished the motor from the sensory nerves and accurately described the eye, brain, liver, and pancreas and the salivary and genital organs. He was first to recognize that the arteries contain blood, not air. His works, which include commentaries on Hippocrates and a treatise on anatomy, were lost.