THE PROCESS OF OXIDATION. 233 



the albuminate of soda. Bat as comparative analyses of this kind 

 are attended with considerable difficulty, and as the concurrent 

 circumstances might possibly invalidate the correctness of this 

 view, we will turn to other investigations connected with this 

 subject. Bernard^ who, as we have already stated, injected a 

 solution of grape-sugar into the veins of dogs and rabbits, thought 

 he could perceive that the sugar not only did not pass into the 

 urine, but that the latter secretion was even rendered alkaline. 

 Without including my previous experiments, which led to pre- 

 cisely opposite results, I have very recently injected grape-sugar, 

 prepared from starch, into the jugular veins of 37 rabbits and 

 dogs ;* but in no single instance was the previously acid urine 

 rendered alkaline; and in no single case was grape-sugar absent 

 from the urine. Quantitative determinations showed that even 

 0*1 of a gramme of grape-sugar could be detected in the urine of a 

 rabbit weighing 2,150 grammes. The greater part of this (O'l of 

 a gramme) of grape-sugar passed into the urine, even when the 

 rabbits had fed before and after its injection on cabbage -leaves, 

 carrots, grass, and other substances rich in alkalies, and the 

 alkaline urine of these animals did not retain its alkaline character, 

 notwithstanding the abundance of alkalies contained in the food, 

 but acquired, in opposition to Bernard's assertion, an acid and 

 often a very intensely acid reaction. Finally, I convinced myself 

 in two cases that rabbits into whose veins very small quantities 

 of starch-sugar had been injected (which might in other cases be 

 detected in the urine) did not void any sugar, provided they had 

 received no succulent food either shortly before or after the 

 experiment, and hence did not require to pass urine. A similar 

 result was observed when urine was artificially discharged by 

 pressure on the region of the bladder. It appears that sugar can 

 only be separated from the blood when there is an excess of 

 water in the latter, for it is only by the prolonged continuance of 

 sugar in the blood that it can be thoroughly consumed ; but the 

 urine here is not rendered alkaline, but strongly acid, as is always 

 the case with fasting rabbits. The sugar, moreover, passes so 

 rapidly into the urine that it may frequently be detected five 

 minutes after its injection (and that even when only 0*1 of a 

 gramme has been injected). This rapid separation of the sugar from 

 the blood, and its decomposition in this fluid, if from a deficiency 

 of water it be retained sufficiently long, seem to favour the 

 hypothesis that the cause of the appearance of sugar in the urine 

 * Ber. d. k. sauhs. Ges. der Wiss. Jahrg. 1852. 



