234 ANDREW JACKSON HOWE. 



portance to himself and the world that even the dawn 

 of the earlier ideas must have remained in his mind as 

 something wonderful. He made no mention of his 

 budding views at Padua, nor upon his arrival at home. 

 Upon his return from the Italian sojourn he entered 

 at once on professional duties, and disclosed nothing 

 to indicate that his mind was engaged in the unfold- 

 ing of a great and novel idea. It is simply known 

 that he engaged in a series of vivisections, and began 

 to write letters to distinguished physicians in various 

 parts of Europe concerning the blood-vessels and the 

 uses of the heart. The conclusion seems to be that 

 the discovery grew upon him so slowly, and after so 

 many false scents, that he could never recall the mo- 

 ment when the scheme in its fullness burst upon his 

 mind. It is quite certain that he expounded his 

 views of the circulation for eight or ten years in the 

 College of Physicians, before he published his "De 

 Motu Cordis et Sanguinis." This work did not appear 

 till 1628, yet in 1619 the author had taught substan- 

 tially the same doctrine from manuscripts. He lec- 

 tured on anatomy, physiology, and surgery as early as 

 1615. 



Harvey is known to have executed vivisections 

 before his classes, in 1619, and to have chosen the 

 lower animals for experimentation in order that he 

 might for a longer time observe the movements of 

 the heart. As he watched the rhythmic movements of 

 the heart of the turtle the animal having been 

 mutilated for the purposes of study he saw there 

 Was alternate contraction and relaxation of the mus- 

 cular tissue of the organ, which corresponded with 

 the outgoing and incoming of the blood ; and he 

 pressed the beating organ in his fingers to ascertain 



