EXCHANGE OF MATEEIAL 



13 



The output in the urine, faeces, and breath was : 



Water. Salts. Carbon. Nitrogen. 



Urine .... 1355 -grins., of which 1280 24 14 19 



Faeces .... 120 85 6 16 2 



Products of respiration . 1867 950 ... 250 



Total output 



3342 



2315 30 280 



21 



A comparison of the totals for intake and output with the 

 weights of the subject before and after the experiment will 

 indicate the oxygen absorbed. As already mentioned, the subject 

 gained 138 grms. in weight. 



From the above data we can make an approximate calculation 

 of the total amount of oxygen absorbed according to the following 

 equation : 



Oxygen = (final weight of the body -f output) - (initial weight + intake) 

 = (70138 + 3342) grms. - (70000 + 2760) grms. 



= 720 grms. 



We now have all the requisite data for a table showing the 

 balance of the exchange of material. 



The results of these investigations showed that the subject had 

 gained 138 grms., containing 41 grms. of carbon. Since there was 

 perfect equilibrium on the balance of nitrogen, the increase in 

 weight cannot be due to an accumulation of protein ; we are there- 

 fore justified in concluding that there is a deposition of non-nitro- 

 genous material. 



From the above data we can estimate fairly accurately whether 

 the 41 grins, of carbon were retained in the form of fat or carbo- 

 hydrate, by noting the size of the respiratory quotient, i.e. the 

 ratio between the carbon dioxide discharged and the oxygen 

 absorbed. If we subtract the 950 grms. of water exhaled from 

 the sum total of the respiratory products, which amounted to 



