432 CHEMISTRY OF THE PROTEIDS CHAP. 



Schiitzenberger l found, in 1874, amongst the products of the 

 autodigestion of yeast, in addition to other substances, also xanthin, 

 hypoxanthin, guanin, and carnin. Salomon, 2 in 1878, observing 

 xanthin in the blood of corpses, while it was absent in freshly drawn 

 arterial blood, was thus led to study the autodigestion of different 

 organs. 3 He especially noticed a doubling in the amount of the hypo- 

 xanthin in muscle, while the quantity in the pancreas or liver 

 remained the same, or was slightly increased. Lehmann, 4 working 

 under Bossel, arrived in 1885 at the conclusion that yeast kept for 

 twenty-four hours in water showed a diminution of hypoxanthin, but 

 an increase in the xanthin + guanin fraction when it was compared 

 with yeast boiled directly with mineral acids. In 1888 Salkowski 5 

 introduced the method of studying the autodigestion of yeast in 

 chloroform water, and showed that watery extract of yeast which 

 had not been sterilised gave a considerable amount of xan thin- 

 bases, and in a second paper 5 confirmed the results previously obtained 

 by Salomon. Schwiening 6 in 1894 showed autodigestion to go on 

 in extracts of organs containing no cellular elements, and that the 

 presence of alkalies was injurious to enzyme action during autolysis, 

 and Biondi 7 in 1896 proved that the enzyme was not trypsin. 

 Okerblom 8 stated to have found amongst the autodigestion-products 

 of the suprarenal : xanthin, 1-methyl xanthin, hypoxanthin, epi- 

 guanin, and a trace of adenin ; but Jones and Whipple, 9 on repeating 

 Okerblom's researches, failed to get 1-methyl xanthin and epiguanin, 

 while they did find guanin and adenin. Their results differed also 

 from Okerblom's in this : Jones and Whipple found no xanthin but 

 large amounts of guanin ; while Okerblom had found xanthin but no 

 guanin. Kutscher, 10 on reinvestigating autodigested yeast, found no 

 base corresponding to the xanthin fraction, while in the hypoxanthin 

 fraction he found guanin and adenin. He expresses the view that 

 xanthin must have disintegrated during the digestion, and in support 

 of this view n he refers to Lehmann, who showed that preformed 



1 Schiitzeuberger, Bull, de la Soc. chim. de Paris (1874), p. 194. 



2 Salomon, Zeit. f. physiol. Chem. 2. 65 (1878). 



3 Salomon, Arch.f. Physiol. 1881, p. 361. 



4 Lehmann, Zeit.f. physiol. Cliem. 9. 563 (1885). 



5 Salkowski, Deutsch. med. Wochensch. 16. (1888) ; Zeit. f. physiol. Chem. 13. 506 

 (1889) ; and Zeit.f. Mm. Med. 1890, Suppl. p. 77. 



6 Schwieniug, Virchow's Arch. 136. 444 (1894). 



7 Biondi, ibid. 144. 373 (1896). 



8 J. Okerblom, Zeit. f. physiol. Chem. 28. 60 (1898). 



9 Walter Jones and Whipple, Amer. Journ. of Physiol. 7. 423 (1902). 



10 Kutscher, Zeit. f. physiol. Chem. 32. 59 (1901). 



11 Kutscher, Sitzb. d. Ges. z. Bef. d. gesammten Xaturwiss. (1900). 



