PENTOSES. 201 



greater importance, not only for the chemistry of plants, but also for 

 the chemical processes in the animal body. 



Pentoses (C 5 Hi O 5 ). 



As a rule the pentoses do not occur as such in nature. They are 

 obtained from animal tissues, organs and fluids as cleavage products 

 of the nucleic acids or nucleoproteins. The pentoses are chiefly obtained 

 from the plant kingdom by the hydrolytic cleavage with dilute mineral 

 acids, of more complex carbohydrates, the so-called pentosans. The 

 pentosans exist very widely distributed in the plant kingdom, and are 

 of especially great importance in the building up of certain plant con- 

 stituents. Methyl pentosans and methyl pentoses also occur in. the 

 plants, and of these, the methyl pentose, rhamnose, which occurs in 

 several glucosides, must be specially mentioned. 



The pentoses were first found in the animal kingdom by SALKOWSKI 

 and JASTROWITZ in the urine of a person addicted to the morphine habit, 

 and later by SALKOWSKI and others in human urine. Small quantities 

 of pentoses have been detected by KULZ and VOGEL l in the urine of 

 diabetics, as also in dogs with pancreas diabetes or phlorhizin diabetes. 

 Pentose has also been found by HAMMARSTEN among the cleavage 

 products of a nucleoprotein obtained from the pancreas, or from the 

 corresponding guanylic acid, and seems also, according to the observa- 

 tions of BLUMENTHAL, to be a constituent of nucleoproteins of various 

 organs, such as the thymus, thyroid, brain, spleen, and liver. In regard 

 to the quantity of pentoses found in the various organs, we must refer 

 to the works of GRUND and of BENDIX and EBSTEIN and MANCiNi. 2 



The pentosans (STONE, SLOWTZOFF) as well as the pentoses are of the 

 greatest importance as foods for herbivorous animals. In regard to the 

 value of the pentoses, the researches of SALKOWSKI, CREMER, NEUBERG, 

 and WoHLGEMUTH 3 upon rabbits and hens show that these animals 

 an utilize the pentoses. The question whether the pentoses are active 

 as glycogen -formers is still an open one (see Chapter VIII). The pen- 



1 Salkowski and Jastrowitz. Centralbl. f. d. med. Wissensch., 1892, 337 and 593; 

 Salkowski, Berl. klin. Wochenschr., 1895; Bial, Zeitschr. f. klin. Med., 39; Bial and 

 Blumenthal, Deutsch. med. Wochenschr., 1901, No. 2; Kiilz and Vogel, Zeitschr. f. 

 Biologic, 32. 



2 Hammarsten Zeitschr. f. physiol. Chem., 19; also Salkowski, Berl. klin. Wochen- 

 schr., 1895; Blumenthal, Zeitschr. f. klin. Med., 34; Grund, Zeitschr. f. physiol. Chem., 

 3o; Bendix and Ebstein, Zeitschr. f. allgemein. Physiol., 2; Mancini, Chem. Centralbl., 

 1906. 



3 Stone, Amer. Chem. Journ., 1-1; Slowtzoff, Zeitschr. f. physiol. Chem., 31; Sal- 

 kowski, ibid. 32; Cremer, Zeitschr. f. Biologic, 29 and 12; Neuberg and Wohlgemuth, 

 Zeitschr. f. physiol. Chem., 35. 



