264 PENTOSURIA 



namely, with mentJiolglycuronic acid and turpentinglycuronic acid. Both of 

 these glycuronic acids have the property of decomposing spontaneously, and as 

 free glycuronic acid also reacts to the orcin test, they may be confounded. We 

 are prevented from making this mistake, first, by the history, as mentholgly- 

 curonic acid and turpentinglycuronic acid are only excreted after the inges- 

 tion of menthol and turpentine; secondly, by the odor of the urine; menthol 

 urine smells of peppermint, turpentine urine of violets. Therefore, in human 

 urine, since the introduction of the orcin test, there can scarcely be any diiB- 

 culty in the recognition of pentose. The circumstances are different in the 

 urine of the herbivora. They frequently take up with their food a mass of 

 pentosan, that is, the anhydrid of pentose. The pentosans have the same rela- 

 tion to pentose that glycogen has to grape sugar. These pentosans are in part 

 excreted as such and give the orcin test, as does pentose, for by heating with 

 hydrochloric acid pentose is developed from pentosan. 



As the urine of the herbivora very frequently has reducing properties and 

 therefore gives a more or less distinct orcin test, confusion with pentose is not 

 impossible. In these cases the phenylhydrazin test must be employed; if this 

 is positive while the fermentation test is negative, pentose is present. If the 

 fermentation test is positive, after fermentation has ceased the phenylhydrazin 

 test must also be positive if pentose is present. 



After this slight digression, we return to the chemical analysis of the 

 urine. If we have under consideration a urine that gives a positive reaction 

 with Trommer's test, the phenylhydrazin test, the orcin and phloroglucin tests 

 for pentose, if the urine is optically inactive and does not ferment, then the 

 patient excreting such a urine has pentosuria. The question now arises, What 

 does this condition indicate? As it is certain that he is excreting sugar, i. e., 

 pentose, there is unquestionably a disturbance in sugar metabolism.. We are 

 then confronted with another question, whether we are dealing with a variety 

 of diabetes mellitus, a pentose diabetes, or something else. If we are dealing 

 with a variety of diabetes mellitus, the combustion of carbohydrates must be 

 diminished, as in the case of diabetes. Such a connection must be thought of, 

 all the more so as Ruff has produced pentose from derivatives of grape sugar 

 by oxidation with potassium permanganate and hydrogen peroxid, and it is 

 possible that the human organism may also carry on this process of oxidation. _ 

 Further, as it is known that the pentose which occurs in nature and enters the 

 body with the food, such as the 1-arabinose and 1-xylose, undergoes only partial 

 combustion even in the healthy, it is not unnatural to explain pentosuria by 

 conceiving that the patient, from the forms of sugar with six carbon atoms, 

 forms pentose. This he incompletely oxidizes, and hence excretes a portion 

 of it. If this view were correct, with the withdraival of starch from the food 

 pentosuria should disappear or at least lessen, and, on the other hand, with 

 the profuse administration of starch or grape sugar the pentosuria should 

 increase. 



_ _ But when we withdraw carbohydrates from patients who excrete pentose, 

 it IS always observed that the pentosuria continues, and apparently in the same 

 degree as formerly, while the administration of even 100 grams of grape sugar 

 after a strict diet free from sugar does not lead to a decided increase of the 



