HTPOXANTBIN. 367 



that it is present in traces, if at all, when the copper method is used. 

 In other words, by the action of nitrous acid, even in presence of 

 urea, adenin is partially changed to hypoxanthin when the silver 

 salts obtained by the old method are treated with nitric acid. Balke 

 has found it in malt-sprouts by the copper method. In the pollen 

 of the fir (Pinus sylvestris) Kresling found hypoxanthin, xanthin, 

 and guanin, but not adenin. In the seeds of Handia dumetorum 

 Vogtherr found hypoxanthin and guanin, but no xanthin. 



Hypoxanthin has been extracted from the pancreas. Adenin and 

 guanin in the pancreas readily change after death into hypoxanthin 

 and xanthin (Inoko). Inasmuch as in the sterile aiito-digestion of 

 yeast, as pointed out above, only adenin and guanin remain it would 

 seem as if trypsin readily destroyed hypoxanthin and xanthin. On 

 the other hand, in the presence of bacteria, possibly owing to the 

 formation of nitrous acid, adenin and guanin are converted, as pointed 

 out by Inoko, into hypoxanthin and xanthin. The otherwise dis- 

 crepant results are thus readily explained. 



For the accidental formation of hypoxanthin from adenin by 

 nitrous acid in the silver method, see page 409. 



When a mixture of guanin, xanthin, and hypoxanthin is allowed 

 to putrefy, the bases decompose and disappear in the order named. 

 Hypoxanthin resists bacterial action the longest, and this corre- 

 sponds with its behavior to reagents (Baginsky). Adenin during 

 putrefaction, in the absence of air, is converted into hypoxanthin 

 and guanin is correspondingly changed into xanthin (Schindler). 

 An amido group is, therefore, replaced by oxygen, and probably goes 

 to form urea. This conversion is a very important fact, since the 

 process of putrefaction, as Hoppe-Seyler has repeatedly pointed out, 

 is analogous to the vital process, and the same chemical change may 

 take place in the animal organs. The same change very probably 

 takes place in the auto-digestion of yeast provided living yeast, and 

 especially bacteria, are present. In sterile auto-digestions, as car- 

 ried on in the presence of an antiseptic, only adenin and guanin are 

 present in appreciable amount. Its formation from adenin can be 

 represented thus : 



C,H,N, + H,0 = C,H ,Np + NH3 . 



Hypoxanthin occurs frequently in plants together with the other 

 members of this group, namely, adenin, guanin, xanthin and its 

 methyl derivatives. The widely distributed character of these bases 

 is due to the presence of a parent substance, viz., nuclein, the neces- 

 sary constituent of all cells capable of development, which under 

 the influence of acids, and probably likewise of cellular enzymes, 

 decomposes into the above mentioned bases. They may, therefore, 

 be considered as the first steps in the retrograde metamorphosis of 

 nearly all of the tissues of animals and plants. 



