250 BIOLOGY. . [Boos n. 



tions upon respiration in man. 1 These observations bear upon 

 man from sixteen to thirty years of age, the experiment lasting 

 from eight to thirteen minutes, between one and two o'clock in 

 the day, during the same interval between repasts, and under the 

 same conditions of muscular exertion. According to them the 

 consumption of carbon in an hour undergoes, in proportion to 

 age, the variations indicated in the following table : 



From 8 to 15 years it is 70'42 



15 to 20 10'76 



20 to 30 

 30 to 40 

 40 to 50 



12 

 11 

 9-17 



50 to 60 11-07 



,, 60 to 70 10-25 



In an old man of 76 years, it is 6 



92 8-5 



102 5-9 



Andral and Gavarret not having noted the weight of the 

 persons under observation, the figures above quoted lose much of 

 their value ; nevertheless, they furnish the confirmation of the 

 general law which we have enunciated above, namely, that the 

 respiratory activity varies in proportion to the intensity of the 

 nutritive movement, that is to say, of life. 



The observations of Scharling complete those of Andral and 

 Gavarret, for they furnish an indication of the weight of the 

 persons. Now these observations prove that oxydation is more 

 energetic in the child than in the adult. A child of nine years 

 consumed by kilogramme and by hour 0'25 of a gramme of carbon ; 

 adults of from twenty-five to twenty-eight yearsonly consumed 

 on an average 0' 12 of a gramme. 



Also, according to Scharling, the difference of sex influences 

 the energy of vital combustion, even before puberty ; in the 

 human species girls consume less carbon than boys. But Andral 

 and Gavarret have moreover shown that the difference is notable 



1 Recherches sur la Quantitt d'Acide Carbonique ExhaU par le Poumon (Ann. 

 de Chim. el de Phys., 2 e serie, 1843). 



