CONCERNING LOW PROTEIN DIETARIES 129 



the saving and collection of the urine than in the case of the 

 faeces. 



That such wide variations should occur in the elimination of 

 nitrogen in the urine with different individuals living on the 

 same diet shows how little reliance can be placed on the urinary 

 nitrogen as a measure of the total nitrogenous metabolism. 

 With single subjects over short periods it is a most unreliable 

 method, even when a correction is added for the nitrogen meta- 

 bolized, but which does not appear in the urine. With batches of 

 men over relatively long periods, the average quantity of nitrogen 

 excreted in the urine may be relied on to some extent, when all 

 sources of fallacy are guarded against and provided for. 



A summary of the results obtained by Chittenden with his 

 eleven subjects shows 



That is, there is actually a lower amount of nitrogen excreted 

 in the urine during the second period, when the nitrogen intake 

 was 9-53 grammes, than during the first period, when it was only 

 8-23 grammes ; further, the quantity of nitrogen lost in the 

 faeces was higher in the third period than in the second period, 

 although the nitrogen intake was considerably less. 



We may conclude this examination of Chittenden's results by 



* Corrected for five days. f Corrected for seven days. 



9 



