GLUCOSE. 291 



indicated ; after boiling, and especially after long standing, there was 

 a very considerable yellow sediment of suboxide of copper. From 

 the result of this experiment I believe that with from 15 to 20 frogs' 

 livers the presence of sugar in this tissue may be distinctly demon- 

 strated. Moreover, I regard this substance as glucose, and not 

 milk-sugar, in consequence of its reducing the oxide of copper far 

 more slowly than is usually the case with milk-sugar. 



Sugar has been sought for in all the fluids in cases of Diabetes, 

 and has been so generally found that it is unnecessary to quote 

 authorities on the subject. It has been found not merely in the 

 urine, blood, and all serous fluids, but also in the saliva, in vomited 

 matters, in the solid excrements, and even in the sweat. 



In a person suffering from well-developed diabetes, and who 

 at the same time perspired very freely, (a combination not often 

 observed,) it was only in the sweat that I failed to detect sugar. 



Origin. The origin of the small quantities of glucose which 

 normally occur in the animal fluids, is so obvious, as hardly to 

 require notice. I will here only remark that little or nothing 

 in the w r ay of conclusion can be deduced in reference to the meta- 

 morphosis of starch or dextrin within the animal organism from 

 experimental attempts to convert starch into sugar by means of 

 saliva, the serum of the blood, renal tissue, &c. ; for any other 

 nitrogenous substance acts just as efficiently, if it be digested for a 

 sufficiently long time with water and starch-paste, in converting a 

 portion of the latter into sugar. The actual substance which, in all 

 probability, effects the conversion of starch into sugar, is, as we have 

 already mentioned, the pancreatic juice. Magendie's experiment,* 

 in which starch was converted into sugar in the circulating blood 

 of a living animal, proves little in relation to the physiological 

 process, since starch does not normally pass into the blood. We 

 shall enter more fully in the consideration of the digestion of starch 

 and of the experiments bearing on this point which have been 

 instituted by Bouchardat and Sandras, Jacubowitsch, Strahl, and 

 others, in a future part of the work. 



But whence originates the enormous quantity of sugar which, 

 in diabetes, is often discharged with the urine ? While no one can 

 doubt that it is for the most part, at all events, derived from vege- 

 table food, it is still a contested question whether the nitrogenous 

 constituents of the animal body may not also contribute to the 

 formation of this substance. Many have assumed it as beyond all 

 * Compt. rend. T. 30, pp. 189-192. 



U 2 



