THE ROYAL SOCIETY OF CANADA 

 Table I 



For the proper elucidation of this table it ought to be stated 

 that the figures for the dingo dog and the black bear represent the 

 average daily output of a single animal as derived, in the case of the 

 first, from observations upon two, and in the case of the second upon 

 four, consecutive days. On the other hand the data for the elephant 

 give merely the amounts of each substance found in one liter of a 

 random specimen, while those for the mouse show the composition 

 of the mixed urine obtained by collecting, as completely as possible, 

 the output of twenty- four mice for twenty-one days. As they stand, 

 therefore, the figures are mutually comparable only in respect of the 

 proportions shown to exist between the different products of purine 

 metabolism. This comparison is effected by reducing all data to a 

 percentage basis as referred to the sum of allantoin, uric acid and purine 

 base nitrogen. It is further facilitated by the calculation of the 

 "uricolytic index." By this we mean the ratio, again as a percentage, 

 of allantoin nitrogen to the sum of uric acid and allantoin nitrogen 

 only; and we take it to indicate specifically the capacity of the animal 

 to effect the final stage of purine catabolism, the conversion of uric 

 acid into allantoin. 



In Table II the results obtained with the four species here for the 

 first time reported upon are compared, in classified series, not only 

 with all earlier ones of our own, but also with the few additional, 

 often imperfect, data that can be collected from other sources.^ 



1 Cf. Hunter, Givens and Guion: J. Biol. Chem., xviii, p. 387, 1914; Hunter and 

 Givens: ibid., xviii, p. 403, 1914; and earlier sources quoted in these papers. 



