Know Thyself 33 



about us, and are intense about it, our whole being, 

 body no less than soul, is fundamentally implicated. 

 Nor does Harvey fail to let us know how his objective 

 discoveries fitted into his deeper conceptions of life 

 and nature. Two aspects especially of his researches 

 brought him face to face with these larger problems. 

 One was his study of the motion of the heart; the 

 other his reflections on the blood as the vital fluid of 

 the body. The highwater mark of his ability as a 

 philosophic biologist is reached, I think, in his handling 

 of these two matters. His main treatise, entitled "An 

 Anatomical Disquisition on the Motion of the Heart 

 and Blood in Animals," is devoted solely to an accurate 

 and full description of the structure and operation of 

 the blood system. Questions of ultimate causes and 

 reasons he hardly touches in this book and when he 

 does, only to show the error of some prevalent teach- 

 ing. "Whether or not," he says, "the heart, besides 

 propelling the blood, giving it motion locally, and dis- 

 tributing it to the body, adds anything else to it, 

 heat, spirit, perfection, must be inquired into by and 

 by and decided upon other grounds." Observable 

 facts first, was his watchword. Casual explanations 

 and appraisements of value and importance must come 

 afterwards. 



Two things in his ability to combine observation and 

 generalization are supremely important. First, he did 

 not for an instant waver in accepting the validity and 

 the worth of the sensuous elements in knowledge. Soc- 



