CHAPTER 2 



The historical development of 

 cardiovascular physiology 



C H A U N C E Y D . LEAKE | The Ohio State University, Columbus, Ohio 



CHAPTER CONTENTS 



Harvey's Predecessors 

 Harvey's Achievement 

 Harvey's Followers 

 Prospect 

 Bibliographic Note 



FROM THE TIME that humaiis started to think and to 

 observe themselves and their surroundings, they have 

 been interested in the way in which Hving things work. 

 Of course we are mostly interested in ourselves: what 

 makes us tick has been the subject of long centuries of 

 search and research. Cross analogies between muscles 

 and bones on the one hand, and levers and tackle on 

 the other, must have early developed. Certainly 

 analogies from levers and tackle were early applied to 

 ideas on muscular motion, and it may very well have 

 been that notions about muscle action suggested the 

 development of various kinds of levers and pulleys. 

 Certainly people must have thought hard how to de- 

 vise ways whereby muscular work could be made 

 easier. Analogies from human feelings were applied to 

 the way in which forces in nature may work. .Animistic 

 ideas still color our language about the movement of 

 the winds and waters. It took many long centuries 

 before functional or physiological generalities could 

 be tentatively expressed. 



Cardiovascular function is central to an under- 

 standing of mammalian and human physiology. The 

 history of this phase of intellectual advance is long 

 and full of intense human interest. It also has had 



great practical significance in stimulating ways by 

 which knowledge of the operation of the heart and 

 blood vessels could be applied to practical medical 

 affairs in the diagnosis, prognosis, prevention, and 

 treatment of disease. It is also stimulating in a practi- 

 cal way to consider how our knowledge of the opera- 

 tion of the heart and blood vessels was obtained. 



The first consistent comprehensive scheme to ex- 

 plain the manner in which animals work was de- 

 veloped by Galen, the great Greek physician to the 

 Roman emperor Marcus Aurelius. His explanation, 

 applicable to those living things we call "mammals," 

 persisted for 1500 years. While it may have been the 

 practical success of cinchona bark in "curing" fevers, 

 which really overthrew Galenical scholasticism in the 

 seventeenth century, it was the theoretical conse- 

 quences of the demonstration of the circulation of the 

 blood in animals, by William Harvey, that eventually 

 removed the arbitrary Galenical system, and es- 

 tablished modern experimental methods to make 

 possible the science of physiology. 



H.'^RVEY S PREDECESSORS 



Through Injury and warfare, with resulting wounds 

 and bleeding, people even in primitive societies uni- 

 versally developed ideas at a very early time about the 

 heart beat, and how warm blood is necessary for life. 

 The relation of the pulse to the heart beat was vaguely 

 appreciated in antiquity, and became formalized in 

 such great static ancient cultures as the Chinese, the 

 Hindu, and the Egyptian. These early notions on the 



