OF SUGAR IN DIABETIC URINE. 205 



synthetically at similar results to those obtained by the 

 more empirical method of direct experiment. 



If we take a solution of cane sugar in water, made so 

 that 100 grains are contained in each looo grain-measures, 

 its density at 60° will be 1038-64. 



Such a solution consists by weight of 100 grains of 

 sugar, and 938'64 grains of water. 



After fermentation there remains 53*74 grains of alco- 

 hol, and 987*18 grains of water. 



Such a mixture of alcohol and water has, according to 

 Gilpin's tables,* a density of 993. 



This figure is very near that obtained in actual fermen- 

 tation. The density of the fermented product is, however, 

 a little higher, about i^ or 2 degrees. This slight excess 

 is to be attributed to the escape of a portion of alcohol 

 with the carbonic acid during fermentation, and to a little 

 soluble matter taken up from the yeast. 



Some effect probably, though I know not of what kind, 

 is likewise produced by the retention in the liquor of more 

 than its own bulk of gaseous carbonic acid in a state of 

 solution. 



It was uniformly found, with solutions of equal strength, 

 that those made with urine showed rather more '^' density 

 lost'^ than those made with water. This is an indication 

 either that changes take place in some of the non-saccha- 

 rine constituents of the urine during fermentation — but 

 changes so slight and so constant in their nature that 

 they do not interfere materially with the accuracy of the 

 mode here proposed for estimating sugar — -or else that 

 urines usually reputed non-saccharine do in reality contain 

 a small quantity of sugar. 



An excessive quantity of yeast was used in these expe- 

 riments in order to hasten the process of fermentation. 

 The quantity of soluble matter taken up from the yeast was 

 * See Ecury's Chemistr^^ tenth edition, vol. ii. p. 343. 



