268 PENTOSURIA 



as a pentose diabetes, for the property of combustion of the pentoses of the 

 food is nowise altered. The same conditions are present here as in leyiilosuria, 

 which Eosin and Laband have lately determined represents an anomaly in 

 the production of levulose, not, however, dependent upon a disturbance of its 

 combustion. I do not believe it can be doubted that in true diabetes we shall 

 ultimately reach the point of separating a group of cases in which the forma- 

 tion of grape sugar in the organism is disturbed; while there is no anomaly 

 of combustion. I mean the cases with slight excretion of sugar ( 1 per cent, or 

 less) and this almost entirely independent of the carbohydrate constituents of 

 the food. Perhaps, also, in many severe cases such a disturbance in the syn- 

 thesis of sugar may be found. 



Pentosuria is therefore an independent disturbance of metabolism, which 

 is characterized by the fact that in this condition an inactive sugar has 

 been found in nature for the first time. Thereby the law that the animal 

 organism and plants can produce only active varieties of sugar has been 

 proven erroneous. A second law, which for a long time was considered 

 incontestable, namely, that the pentoses are the sugar of the vegetable king- 

 dom only, and do not occur at all in the animal kingdom, has also been 

 nullified. 



We must separate true chronic pentosuria from alimentary pentosuria. 

 A large number of individuals do not possess the property of oxidizing large 

 amounts of pentosan introduced with the food, but excrete a portion of these 

 pentosans as pentose. This is alimentary pentosuria. The amount of pentose 

 excreted is about 0.2 to 0.5 per cent. This pentose always arises from the 

 pentosans which are taken up with the food, for the most part in the dextro- 

 rotary l-arabinose contained in fruits. This phenomenon we generally see 

 in the summer when fruit is freely eaten (cherries, strawberries, whortleber- 

 ries, plums). 



This alimentary pentosuria has nothing in common with chronic pento- 

 suria, in which arabinose also occurs ; ' here not the dextro-rotary but the inac- 

 tive appears in the urine. We now find, however, that besides chronic pen- 

 tosuria the alimentary type may also exist, and I am in possession of records 

 of cases in which both the inactive arabinose and the dextro-rotary appear in 

 the urine. The proof of this has been deduced as follows: first, the urine 

 without fermenting was dextro-rotary; secondly, only pentosazone could be 

 produced from it ; and thirdly, according to Neuberg, a solution of the osazone 

 in pyridin alcohol proved dextro-rotary. 



True chronic pentosuria, as we have seen, is characterized by the fact that, 

 independently of food, inactive arabinose is excreted continuously. The 

 amount of inactive arabinose varies in this condition between 0.3 and 1 per 

 cent, by Knapp's method of titration. 



We find, however, cases also of chronic diabetes that are complicated by 

 pentosuria, i. e., showing a slight excretion of pentose. To this group belong 

 a number of diabetics in whose urine very small amounts of pentose have been 

 demonstrated, as shown by Kiilz and Vogel. In these cases the pentose has 

 not the slightest clinical importance so far as can be determined at this time. 

 It occurs in such minute traces that its presence cannot be detected by our 



