When the King made Oxford his headquarters, Harvey was with him, and was appointed head of Merton College. But in 1646, on Oxford surrendering to the Parliamentary forces, he gave up his wardenship and quitted the city. Having no call to take an active part in the political contest, and now verging on threescore-and-ten, he retired from his position of physician to the King and went to London, where he was hospitably entertained in the houses of his brothers, who were wealthy merchants in the City. Here he no doubt once again devoted himself to scientific observation, the nature of which became evident, when in 1651 he was persuaded, somewhat against his own inclination, by his friend, Dr. George Ent, to allow the publication of his book on “The Generation of Animals.” In this work he appears as a pioneer in the difficult science of Embryology, working under most adverse conditions, for he had no microscope worthy of the name. Whilst, therefore, of no great value in the light of our present knowledge, it is a monument of the author’s industry and of his enthusiastic devotion to physiological research. It contains a great number of acute and interesting observations; and he had evidently made many more, for he says that his papers on the Generation of Insects were lost as a result of the tumults which arose at the outbreak of the Civil War. He told Aubrey that no grief was so crucifying to him as the loss of these papers. The King took a direct personal interest in these investigations,[16] and supplied him with deer from the Royal Parks in order to further them. [16] De Generatione Ex. lxix