OBSERVATIONS ON THE NITROGENOUS METABOLISM 

 OF THE CAT, ESPECIALLY ON THE EXCRETION 

 OF URIC ACID AND ALLANTOIN.* 



BY LAFAYETTE B. MENDEL AND ERNEST W. BROWN. 



THE experiments which form a part of this paper were 

 begun in continuation of a previous investigation in this 

 laboratory on the excretion of kynurenic acid in various 

 animals, f Our earlier experience had shown that kynurenic 

 acid is absent from the urine of the cat during both fasting 

 and proteid feeding, conditions under which this acid is reg- 

 ularly found in the dog. The largely increased excretion of 

 kynurenic acid found in the dog during the increased proteid 

 metabolism caused by phlorhizin administration led us to try 

 similar experiments on the cat. It was reasoned that if 

 kynurenic acid were a normal product of metabolism which 

 is ordinarily destroyed as soon as it is formed in this animal, 

 then by bringing about an unusually marked stimulation of 

 metabolism this product might appear, owing to the temporary 

 inability of the organism to utilize all the intermediary sub- 

 stances formed. Extracts from protocols follow : 



Phlorhizin experiments. I. A medium sized cat received 

 subcutaneously in four doses 1.5 grams phlorhizin dissolved in 

 dilute sodium carbonate solution. The urine of two days, in- 

 cluding the day of injection 208 c.c. was examined for 

 kynurenic acid by Capaldi's $ method with negative results. 



II. A very large cat received subcutaneously a total of two 

 grams of phlorhizin in two doses with an interval of eighteen 

 hours. The greater portion of the urine of four days 209 c.c. 



* Reprinted from the Amer. Jour. Physiol., vol. iii. 

 t Mendel and Jackson, Amer. Jour. Physiol., 1898, ii, p. 1. 

 J Capaldi, Zeitschrift fiir physiol. Chemie, 1897, xxiii, p. 92. 

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