ACTION OF THE HEART. 125 



In the embryo the average number of pulses in a minute is 150 

 Just after birth ...... from 140 to 130 



During the first year . . . . . 130 to 115 



During the second year 115 to 100 



During the third year 100 to 90 



About the seventh year 90 to 85 



About the fourteenth year, the average number 



of pulses in a minute is from . . . 85 to 80 



In adult age 80 to 70 



In old age 70 to 60 



In decrepitude 75 to 65 



In persons of sanguine temperament, the heart acts 

 somewhat more frequently than in those of the phleg- 

 matic ; and in the female sex more frequently than in the 

 male. 



After a meal its action is accelerated, and still more so 

 during bodily exertion or mental excitement ; it is slower 

 during sleep. The effect of disease in producing temporary 

 increase or diminution of the heart's action is well known. 

 From the observation of several experimenters, it appears 

 that, in the state of health, the pulse is most frequent in 

 the morning, and becomes gradually slower as the day 

 advances : and that this diminution of frequency is both 

 more regular and more rapid in the evening than in the 

 morning. It is found, also, that as a general rule, the 

 pulse, especially in the adult male, is more frequent in the 

 standing than in the sitting posture, and in the latter than 

 in the recumbent position; the difference being greatest 

 between the standing and the sitting posture. The effect 

 of change of posture is greater as the frequency of the 

 pulse is greater, and, accordingly, is more marked in the 

 morning than in the evening. Dr. Guy, by supporting 

 the body in different postures, without the aid of muscular 

 effort of the individual, has proved that the increased 

 frequency of the pulse in the sitting and standing positions 

 is dependent upon the muscular exertion engaged in main- 

 taining them ; the usual effect of these postures on the 



