272 



PHYSIOLOGY 



CHAP. 



on two healthy individuals 25 years of age. The delay between 

 the radial pulse and the carotid for the wave b' = 3 - 93 mm. = 0'0786 

 seconds, for the wave/' 3 '96 mm. = OOV92 seconds. 



Since the distance from the semilunar valves to the point on 

 the carotid at which the sphygmograph was applied was 20 cm. 

 and to the corresponding point on the radial 80 cm., the time 

 difference found corresponded to a length of 60 cm. From these 

 data the time of transmission of the wave I' from heart to carotid 

 can be calculated : 



3-93 : .'60 : 20 ; X - 1'31 mm. = 0'0262 seconds ; 

 and from heart to radial : 



3-93 + 1-31 =5-24 mm. = 0-1048 seconds. 



By a similar calculation the propagation of the wave /' from 

 heart to carotid is found to be : 



3-96 : .c = 60 : 20 ; z = 1-32 nun. = 0-0264 seconds : 

 and from heart to radial : 



3-96 + 1-32 = 5-28 mm. = 0-1056 seconds. 



Repeating the same measurements and calculations for the 

 single series of tracings obtained on the two young men, Edgren 

 obtained the results appended on the following table : 



From tliesa data Edgreu found it easy to calculate the rate of 

 transmission of the two waves, i.e. the distance they traversed in 

 one second (the unit of time). 



The results are given in the following table : 



