554 ENDOTRYPTASE AND PHILOTHION. 



form after digestion Las been proceeding for an hour at 37 C. 

 The amount of sulphuric acid, on the other hand, increases but 

 slightly. The nitrogenous constituents of the expressed yeast 

 juice undergo decomposition in such a manner that, at the close 

 of the autodigestion process, about 30 per cent, of the nitrogen in 

 the digestion products is in the form of bases, 70 per cent, being 

 allocated to the amino acids, the proportion being the same as 

 that in which these bodies are found in the fresh yeast juice 

 freed from albumen. The xanthin bodies, which are present in far 

 smaller amount (50-60 mgrms. per 100 c.c. of yeast juice), 

 exhibit an interesting behaviour, inasmuch as, under normal 

 conditions, they are still present in a latent form after the auto- 

 digestion of the yeast juice, and are only revealed by boiling with 

 acids. This latent condition is probably due to the carbon dioxide 

 appearing in the yeast juice in consequence of the fermentation. 



The more intimate characterisation of the several fission 

 products was effected by Kutscher, with the aid of Kossel's 

 methods. In a recently published work, KUTSCHER and LOH- 

 MANN (I.) give the following series of fission products, obtained 

 by the autofermentation of beer yeast suspended in toluol water : 

 guanin (abundant), adenin (abundant), xanthin (traces), hypo- 

 xanthin (traces), histidin, leucin, arginin, ty rosin, lysin, aspartic 

 acid, glutamic acid (hitherto undetected), and ammonia (little). 

 SHIGA (I.) recently ascertained that the amount of xanthin 

 increases continuously during the digestion of expressed yeast 

 juice ; but that guanin is decomposed, even when added in afresh 

 state ; w r hilst adenin and hypoxanthin fluctuate. According to 

 Shiga, the arginin is partially decomposed by an enzyme 

 ("arginase") discovered in yeast juice, into urea and ornithin 

 (a-S-diaminovalerianic acid), a process that had been previously 

 observed in the case of animal organs by KOSSEL and DAKIN (I.). 



Finally, Kutscher succeeded in also detecting cholin as a fission 

 product of yeast lecithin. This disposes of the hypothesis that 

 cholin always originates entirely in the unfermented liquid (mash, 

 wort, molasses, and must). The discovery of cholin is important, 

 inasmuch as it is also capable of furnishing an explanation of the 

 appearance of glycerine, namely, that, as mentioned on p. 493, 

 vol. ii., the same may result from the decomposition of lecithin into 

 fatty acids, cholin, and glycerophosphoric acid . Whether the other 

 organic bases found in fermented liquids or their distillates (see 

 p. 510, vol. ii.) owe their formation to the action of endotryptase 

 must be regarded as at least doubtful. To this category belong the 

 organic bases discovered in white wine by Briicke in 1855, tne 

 trimethylamine found in wine by E. LUDWIG (I.) in 1867, the 

 alkaloidal bases found in fermenting solutions of saccharose by 

 OSER (I.), in beer by LERMER (I.), and in white wines by GUERIN 

 (I.), as well as the collidin found by KRAMER and A. PINNER (I.), 

 and the bases which are regarded by BRAND and STOEIIR (II.) as 



