LUDWIG S GEArHIC METHOD — EFFECTS OF EMOTION. 9 



But no one, except those who have worked with him, can 

 understand what such " co-operation " meant. 



The graphic method introduced by Ludwig for the purpose- 

 of measuring the blood pressure, was adapted by Volkman to 

 the registration of the pulse in man, and the same method has 

 been modified and rendered more easily applicable at the bed- 

 side by Marey and Chauveau, to whom we chiefly owe our know- 

 ledge of the modifications in the form of the apex-beat and of 

 the pulse curve. It is to Ludwig and his scholars, however,, 

 that we owe the greater part of our knowledge of the mechanism 

 of the circulation and of the varying distribution of the blood 

 in various parts of the body. 



The efiect of emotion upon the heart was carefully noted by 

 Harvey, who says : " For every affection of mind which is 

 attended with pain or pleasure, hope or fear is the cause of an 

 agitation v/hose influence extends to the heart.* 



Not only was Harvey well acquainted with the fact that the 

 beats of the heart vary very much in strergth and rate, but he 

 also knew that the circulation in various parts of the body may 

 be very difieient 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, habit of body, and other contingent 

 circumstances, external as well as internal, natural, or non- 

 natural. For it does not course through intricate 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 How 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 vigour, 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 



* The Works of Wiliiam Harvey, Sydenham Society's edition, p. 70. 



