PENTOSURIA 265 



pentosuria. From these results it is obvious that pentose in the animal organ- 

 ism is not formed by the oxidation of hexose, i. e., the varieties of sugar with 

 six atoms of carbon or their multiples. 



This to some extent also answers the question whether pentosuria is a 

 variety of diabetes mellitus. The latter disease is characterized Ijy the fact 

 that the power to burn starches and hexoses is diminished. That this is not 

 true of pentosuria, at least not of all cases of pentosuria, was shown by Bial 

 and myself, for the administration at once of 100 grams of grape sugar caused 

 no glycosuria. The combustion of d-galactose in our case of pentosuria was 

 also entirely normal. It follows from this that the patient with pentosuria 

 has no greater tendency to alimentary glycosuria than the healthy; hence if 

 we look upon alimentary glycosuria as a proof of the existence of diabetes 

 mellitus, the urine of the pentosuric is in this respect also entirely negative. 

 There is good ground for the supposition that pentosuria is a pentose diabetes, 

 in which metabolism for sugar with six atoms of carbon is normal, while the 

 property of comiustion for pentose is diminished or has entirely ceased. With 

 food in the form of grain and fruit, and in beer and tea we ingest a certain 

 amount of pentosans; it is quite possible that pentosans are changed into 

 pentose in the stomach by the action of hydrochloric acid; but the organism 

 is incapable of oxidizing them and they are therefore excreted. This hypoth- 

 esis is accepted by ISTaunyn and Llithje, and by others. Can this view be 

 possible ? 



The pentose which we ingest with our food is the dextro-rotary 1-arabinose, 

 while, as we know from the investigations of Carl Neuberg, inactive arabinose 

 also occurs in the urine. Since inactive arabinose, as the researches of Emil 

 Fischer have shown, can only occur by the combination of d-arabinose and 

 1-arabinose, the organism must, in addition to 1-arabinose, also furnish d-arabi- 

 nose; so that i-arabinose may be formed. 



The question whether the organism contains pentose groups has been dis- 

 cussed for a long time. As is well known, Hammarsten found in the nucleo- 

 proteid of the pancreas a reducing substance which he assumed to be pentose. 

 E. Salkowski has produced phenylosazone, and, upon the basis of an analysis 

 of the same, has determined with certainty that the reducing substance is pen- 

 tose. On account of the abundant furfurol formation which is said to be char- 

 acteristic of pentose, and which upon decomposition was shown to be present 

 in the nucleo-proteids from various animal organs, and on account of the 

 production of phenylosazones at the melting point of pentosazone, 157° to 

 160° C, I have maintained that all animal nucleins contain a pentose group, 

 and that the pentose group is characteristic of nucleins Just as is the group of 

 xanthin bases, for I found no proteids which contain pentose except nucleins. 

 I have also held that when an albumin body gives the phloroglucin test for 

 pentose we are justified in declaring it to contain nuclein. This view at the 

 time appeared to be decidedly opposed to the prevailing opinion. ^ A. Kossel 

 and Neumann had, two years previously, found no pentose group in nuclemic 

 acid of the thymus gland. The former denied absolutely the presence of a 

 carbohydrate group in the spermatic nucleinic acid. Noll, the pupil of A. 

 Kossel, forbore entering into this discussion. He believes that we must dis- 



liu^' ks^^.. 



