346 THE CIRCULATION OF THE BLOOD. [CHAP. XXVIII. 



TABLE OP THE AVERAGE FREQUENCY OF THE HEART'S ACTION AND OF THE 

 PULSE AT DIFFERENT AGES. 



At birth 140 



Infancy 120 



Childhood '. . 100 



Youth f v ' 90 



Adult age .75 



Old age 70 



Decrepitude 7580 



In general the frequency of the heart's action and of the pulse in 

 the female exceeds that of the male, after the seventh year ; if the 

 average pulse of the adult male be stated at 70, that of the adult 

 female may be put down at 80. 



The heart's action is seldom less frequent than 45 or 50 in 

 health ; Heberden has counted it as low as 42, 30, and even 26 in 

 healthy males ; and Fordyce counted it in one case 26 in an old 

 man, and in another 20. In cases of chronic disease of the brain 

 it falls very low. We have ourselves counted it as low as 16 in one 

 of these cases for months together. 



According to the researches of Drs. Knox and Guy, the fre- 

 quency of the heart's action (and the consequent frequency of the 

 pulse) varies at different periods of the day. It is most frequent in 

 the morning, and becomes gradually slower as the day advances. 

 The diminution is most marked at night.* 



Posture exercises a remarkable influence on the frequency of the 

 heart's action. The law is, that the frequency is the greatest in the 

 erect position, next to that, in the sitting, and least in the hori- 

 zontal posture. The following table has been framed by Dr. Guy 

 from the results of sixty-six observations in the male, and twenty- 

 seven in the female. 



TABLE OF THE FREQUENCY OF THE HEART'S ACTION IN DIFFERENT 



POSTURES. 

 Standing. Sitting. Lying. Differences. 



Males .81 71 66 10, 5, 15 



Females . 91 84 80 7, 4, 11 



These observations denote the curious fact that posture influences 

 the frequency of the pulse less in the female than in the male, and 

 from another series of more numerous observations, Dr. Guy 

 deduces that the effect of change of posture on the frequency of 

 the heart's action in the male, is more than twice as great as in 

 the female. 



* See Graves's Dub. Hosp. Rep., vol. vi., and Dr. Guy's art. Pulse, Cyclo. 

 Anat. and Phys. 



