Some 350 years ago William Harvey,a young Englishman,went to the university of padua in Italy to study medicine.At that time doctors had strange notions about the work of the heart and the movement of blood through the body.They thought that the blood moved backward and forward like ebb and flow of the tides.They thought that one kind of blood was made in the liver.The heart,they believed,made another kind of blood.Another wrong idea was that arteries carried air to all parts of the body and that only veins carried blood.How blood could get from one side of the heart to the other was a mystery,since there is a thick wall between the two sides.The doctors of the time argued that there must be tiny holes in the wall for the blood to get through.Harvey wondered about the truth of these ideas when they were thought to him.He decided to find out for himself.When Harvey finished his work at the university,he returned to England and became a successful doctor.Before long he was appointed court physician to the king.For many years Harvey studied the work of the heart and the flow of the blood by experimenting with animals.He studied his human patients carefully,too.Not till he was sure he had discovered the truth about the circulation of blood did he publish the results of his experiments.The book he wrote,although it is now over 300 years old,is still worth reading.In it Harvey correctly describes the circulation of the blood.He was the very first person to do so.Harvey's discoveries were not accepted at once by the other physicians of his time .Many people decided that he was crazy and would not trust him as their doctor.Before his death,however,most people knew that he was right.Today he is considered one of the greatest scientists of all time.
