INFLUENCE OF DIGESTION. 433 



portion to the muscular development of the individual ; but 

 there is an important difference connected with the variations 

 with age, which depends upon the condition of the generative 

 system of the female. 



The absolute increase in the evolution of carbonic acid 

 with age in the female is arrested at the time of puberty, 

 and remains stationary during the entire menstrual period, 

 provided the menstrual flow occur with regularity. During 

 this time, the average exhalation per hour is 7M cubic inches. 

 After the cessation of the menses, the quantity gradually 

 increases, until at the age of sixty it amounts to 915 cubic 

 inches per hour. From the age of sixty to eighty-two, the 

 quantity diminishes to 793, and finally to 670 cubic inches. 



When the menses are suppressed, there is an increase in 

 the exhalation of carbonic acid, w T hich continues until the flow 

 becomes reestablished. In a case o,f pregnancy the exhalation 

 was increased to about 885 cubic inches. 1 



Influence of Digestion. Almost all observers agree that 

 the exhalation of carbonic acid is increased during digestion. 

 Lavoisier and Seguin found that in repose and fasting, the 

 quantity exhaled per hour was 1,210 cubic inches ; which was 

 raised to^.,800 and 1,900 during digestion. 3 Numerous ex- 

 periments on animals have confirmed this statement. A very 

 interesting series of observations on this point was made by 

 Vierordt upon his own person. Taking his dinner at from 

 12'30 to 1 P. M., having noted the frequency of the pulse 

 and respirations and the exhalation of carbonic acid at 12, 

 he found at 2 p. M. the pulse and respirations increased in 

 frequency, the volume of expired air augmented, and that 

 the carbonic acid exhaled had increased from 15'77 to 18-22 

 cubic inches per minute. In order to ascertain that this 



1 The above facts, showing the peculiar influence of the condition of the genera- 

 tive organs in the female, are among the most important results of the observa- 

 tions of Andral and Gavarret. Loc. cit. 



a Cyclopcedia of Anatomy and Physiology, vol. iv., part i., pp. 346, 347. 

 28 



