THE GASEOUS EXCRETION. 



385 



Other experiments are in general good agreement with 

 these. The effect of work in the fasting animal is seen almost 

 immediately. In the last experiments the respiratory quotient 

 is greater than unity. This may be due in part to slight errors 

 in observation, but it should be remembered that there are 

 classes of compounds in which such a result would always fol- 

 low. Such compounds are not common articles of food, but 

 often make a part of certain vegetable foods. The complete 

 oxidation of tartaric acid, for example, would yield a quotient 

 of 1.6. 



The quotient may sometimes be high, as intimated above, 

 if the oxygen has been at first absorbed to form compounds 

 relatively rich in oxygen, which are later broken down rapidly, 

 under working or other conditions. If an observation is made 

 just at this period the excess of CO 2 liberated would present 

 an abnormal result. For characteristic results the observation 

 periods should be as long as possible. 



Illustrative Case. Some idea of the importance of the 

 respiratory coefficient determination may be obtained from a 

 consideration of the following assumed case in which the con- 

 ditions are made somewhat ideal for simplicity of calculation. 

 The numerical values given are such as might be obtained from 

 the mean of several 24-hour experiments in a large respiration 

 chamber. The diet is assumed to be abundant and the tests 

 begun after a condition of practical nitrogen equilibrium is 

 reached. 



Initial weight 75 kilograms 



Final weight 75-05 kilograms 



INCOME OBSERVED. 



26 



