MODERN DEVELOPMENTS OF HARVEY's WORK. 4G5 



Mitwirkuug." But no one except those wlio have worked with hiin can 

 understaud what such cooperation meant. 



The graphic method uitroduced by Ludwig for the purpose of measur- 

 ing the bkiod pressure was adapted by Yolkmaun to the registration of 

 the pulse in man, and the same method has been moditied and rendered 

 more easily applicable at the bedside by Marey and Chauveau, to whom 

 we chiefly owe our knowledge of the modifications in the form of the 

 ;il)ex beat and of the pnlse curve. It is to Ludwig and his scholars, 

 liowever, that we owe the greater part of onr knowledge of the mechan- 

 ism of the circulation and of the varying distribution of the blood in 

 varions parts of the body. 



The effect of emotion upon tlie heart was carefully noted by Harvey, 

 who says: ''For every affection of the mind which is attended with 

 pain or pleasure, hope or fear is the cause of an agitation whose influ- 

 ence extends to the heart." ^ 



-Not only was Harvey well acquainted with the fact that the beats of 

 the heart vary very mucli in strength and force, but he also knew that 

 the circulation in various parts of the body may be very different at 

 one and the same time. He says: 



"It is manifest that the blood in its course does not everywhere pass 

 with the same celerity, neither with the same force in all places and at 

 all times, but that it varies greatly according to age, sex, temperament, 

 hal)it of body, and other contingent circumstances, external as well as 

 internal, natural or nonnatural. For it doea not course through intri- 

 cate and obstructed passages with the same readiness that it does 

 through straight, unimpeded, and pervious channels. Neither does it 

 run through close, hard, and crowded parts with the same velocity as 

 through spongy, soft, and permeable tissues. Neither does it flow and 

 penetrate with such swiftness when the impulse (of the heart) is slow 

 and weak, as when this is forcible and frequent, in which case the blood 

 is driven onwards with vigor and in large quantity. 



"And what, indeed, is more deserving of attention than the fact that 

 in almost every affection, appetite, hope, or fear, our body suffers, the 

 countenance changes, and the blood appears to course hither and 

 thither? In anger, the eyes are fiery and the pupils contracted; in 

 modesty, the cheeks are suffused with blushes; in fear and under a 

 sense of infamy and of shame, the face is pale, but the ears burn as if 

 for the evil they heard or were to hear; in lust, how quickly is the 

 member distended with blood and erected." - 



Harvey's great contemi)orary, Milton, though so violently opposed to 

 him in politics, would certainly not remain in ignorance of Harvey's 

 work, and he has noted the changes in the color of the face produced 

 by emotions. In describing the behavior of Satan on his journey from 

 hell to Paradise, he says: 



Thus while be spake, each passion dimm'd his face, 

 Thrice changed with pale — ire, envy, and despair. 

 Which marr'd his borrow'd visage.' 



' "The Works of William Harvey," Sydenham Society's edition, paj;e 70. 



2 Ibid., pages 128-129. 



3 Paradise Lost, by John Milton, Book IV, page 85. 



SM 94 30 



