126 THE CIRCULATION. 



pulse being almost entirely prevented when the usually 

 attendant muscular exertion was rendered unnecessary. 

 The effect of food, like that of change of posture, is greater 

 in the morning than in the evening. According to Parrot, 

 the frequency of the pulse increases in a corresponding 

 ratio with the elevation above the sea ; and Dr. Frankland 

 informed the author, that at the summit of Mont Blanc his 

 pulse was about double the ordinary standard all the time 

 he was there. After six hours' perfect rest and sleep at 

 the top, it was 1 2O, on descending to the corridor it fell to 

 108, at the Grands Mulets it was 88, at Chamounix 56; 

 normally, his pulse is 60. 



In health there is observed a nearly uniform relation 

 between the frequency of the pulse and of the respirations; 

 the proportion being, on an average, one of the latter to 

 three or four of the former. The same relation is generally 

 maintained in the cases in which the pulse is naturally 

 accelerated, as after food or exercise ; but in disease this 

 relation usually ceases to exist. In many affections accom- 

 panied with increased frequency of the pulse, the respira- 

 tion, is, indeed, also accelerated, yet the degree of its 

 acceleration bears no definite proportion to the increased 

 number of the heart's actions : and in many other cases, 

 the pulse becomes more frequent without any accompany- 

 ing increase in the number of respirations ; or, the respi- 

 ration alone may be accelerated, the number of pulsations 

 remaining stationary, or even falling below the ordinary 

 standard. (On the whole of this subject the article Puhc 

 by Dr. Guy, in the Cyclopaedia of Anatomy and Physiology, 

 may be advantageously consulted.) 



The force with which the left ventricle of the heart con- 

 tracts is about double that exerted by the contraction of 

 the right : being equal (according to Valentin) to about 

 T ~-th of the weight of the whole body, that of the right 

 being equal only to -i- -^ f the same. This difference 

 in the amount of force exerted bv the contraction of the two 



