THE AMINO ACIDS 



of the urinary constituents. He, therefore, first de- 

 vised a method, in each instance short and accurate, 

 for the estimation of every important nitrogenous 

 constituent of the urine, together with methods for the 

 determination of sulphur containing compounds, and, 

 secondly, with the aid of these methods made complete 

 analysis of normal urines. In order to make the factor 

 of food protein as evident as possible, diets rich in 

 protein were fed and were succeeded by rations 

 markedly deficient in nitrogenous substances although 

 containing a sufficiency of energy yielding substances. 

 As showing the wide range of variation on the two 

 diets a typical example of the urinary composition 

 follows : 



Nitrogen rich diet Nitrogen poor diet 



Volume of urine 



Total Nitrogen 



Urea-Nitrogen 



Ammonia-Nitrogen 



Uric acid-Nitrogen 



Kreatinine-Nitrogen 



Undetermined 



Nitrogen 

 Total SO 3 

 Inorganic SO 3 

 Ethereal SO 3 

 Neutral SO 3 



The general laws deduced by Folin as a result of 

 urinary analysis are : 



1. Kreatinine. The absolute quantity of kreatinine 

 eliminated on a meat- free diet is a constant quantity, 



