INFLUENCE OF SEX ON METABOLISM. 177 



cases the subjects were fairly quiet, although modern conditions for 

 basal measurements were not obtained. 



That the question of body-weight was seriously considered by 

 Andral and Gavarret is shown by a portion of their discussion, but 

 they discard this method of comparison as irrational, maintaining 

 that while a woman 25 years old weighs much more than a child 10 

 to 14 years old, she produces no more carbon dioxide. They further 

 contend that at the menopause the body-weight of women does not 

 necessarily increase, and they have shown that the exhaled carbon 

 dioxide at that time continually increases. It is a matter of regret to 

 modern writers that, although the body-weights of the subjects were 

 known to these investigators, they did not publish them. 



Special emphasis was laid by Andral and Gavarret upon the influence 

 of puberty on metabolism. They maintain that with boys the carbon 

 dioxide exhaled increases suddenly to a large amount at the time of 

 puberty, while with girls, on the contrary, the carbon dioxide excretion 

 suddenly ceases to increase at this period and remains nearly stationary 

 until the menopause. It then suddenly increases in a very remarkable 

 manner, and finally, as with man, decreases in proportion to the 

 approach to extreme old age. 



Speck 1 studied only three children within the age-range observed 

 by us (a girl of 10 years, a girl of 13 years, and a boy of 13 years), 

 and his conclusions were largely based upon experiments made with 

 older individuals; hence they have little immediate significance in 

 our discussion. 



Most of the discussion as to the difference between the sexes in the 

 classic paper of Magnus-Levy and Falk 2 pertains to the ages beyond 

 those of childhood. According to their results, the total metabolism 

 of boys during the years of puberty did not exceed that of adult normal 

 men. With some of the boys the metabolism was less and with some 

 approximately the same as that found with adult men. They men- 

 tion particularly one boy, accustomed to metabolism experiments, 

 who was studied when he was 16 years old and weighed 57.5 kg., and 

 again 6 years later, when he was 10 kg. heavier. During the period 

 of establishment of puberty the oxygen consumption was 235.6 c. c. 

 per minute and the carbon-dioxide production 192.2 c. c. When 

 puberty had been fully established, the oxygen consumption was 

 231.3 c. c. and the carbon-dioxide production 200.2 c. c. per minute. 

 In other words, approximately the same values were found at both 

 times. In the later stages of the period of pubertal change, therefore, 

 the total metabolism corresponded to that found after puberty had 

 been fully established. Since there was an increase in weight, the 

 metabolism per kilogram of body-weight obviously decreased, i. e., 



1 Speck, Physiologie des menschlichen Athmens, Leipsic, 1892, p. 217. 



2 Magnus-Levy and Falk, Archiv f. Anat. u. Physiol., 1899, Suppbd., p. 314. 



