176 THE MOTION OF THE BLOOD. 



canal, and in those also whose pulsation can be otherwise dis- 

 covered, as in the eye and ear. The effect upon the arteries 

 has been called their diastole, and is perfectly correspondent and 

 synchronous with the systole of the heart," in vessels not distant 

 from it ; but, in distant arteries, the pulse has long been ob- 

 served sometimes a very little later than the systole of the heart. 

 If an artery of tolerable size is divided, the blood escapes in 

 jerks ; if of smaller dimensions, it flows continuously, but is pro- 

 jected further at the moment of the pulse ; and if the artery is 

 very small, it flows in an uniform stream. 



" The quickness of the heart's pulsations during health varies 

 indefinitely; chiefly from age, but also from other conditions 

 which at all ages form the peculiar constitution of an individual, 

 so that we can lay down no rule on this point. I may, however, be 

 permitted to mention the varieties which I have generally found in 

 our climate 8 at different ages, beginning with the new-born infant, 

 in which, while placidly sleeping, it is about 140 in a minute. 

 Towards the end of the first year, about 124? 



second year 110 



. third and fourth year - 96 



When the first teeth begin to drop out 86 



At puberty about - 80 



At manhood about - - 75 



About sixty - 60 



" In those more advanced, I have scarcely twice found it alike." 

 Like many others, I have counted it distinctly before birth, by 

 applying the stethoscope to one side of the mother's abdomen. 

 My observations have been made near the end of pregnancy, 

 and I have counted 128 pulsations in a minute, while the mother's 

 pulse was but about 80. 



" The pulse is, caeteris paribus, more frequent in women than 

 in men, and in short than in tall persons. A more constant 

 fact, however, is its greater slowness in the inhabitants of cold 

 climates. l 



" Its greater frequency after meals and the discharge of semen, 

 during continued watchfulness, exercise, or mental excitement, 

 is universally known." 



8 " My observations differ but little from those made by W. Heberden in 

 England, Med. Trans, vol. ii. p. 21. sq." 



* " J. H. Schonheyder, De Resolutions el Impotentia motus Muscularis. Hafn. 

 1768. p. 15. With which work compare the observations of F. Gabr. Sulzer, 

 Naturgesch. des Hamsters, p. 169." 



