THE NUCLEINIC ACIDS. 97 



OH 



C 6 H 9 5 -P C 5 



d 

 OH, | 



, 

 \P-C,H 3 N 2 0, 



Thyminic acid differs from the nucleinic acids proper in its ready 

 solubility in cold water, and in the fact that it is not precipitated 

 from its solutions by the mineral acids. Like the nucleinic acids, it 

 gives a precipitate with albumins or primary albumoses in acetic 

 acid solution, but, in contradistinction to the nucleinic acids, this 

 precipitate is soluble in hydrochloric acid and in solutions of many 

 salts. 



The thyminic acid radicle contains the carbohydrate group or 

 groups of the nucleinic acid molecule ; the entire amount of phos- 

 phoric acid ; a methyl-uracil complex ; and in some possibly a simple 

 uracil, besides other bodies which are still unknown. The relation 

 of the nucleinic acids to the nucleins and its various decomposition- 

 products can accordingly be represented by the following schema : 



Nuclein 



Nucleinic acid 



Xanthin-bases Thyminic acid 

 and cytosin 



Unknown bodies 



\. 



Carbohydrate Phosphoric acid 



complex 



Possibly, however, the decomposition does not proceed in so 

 simple a manner in all cases. Osborne has thus shown that on boil- 

 ing tritico-nucleinic acid with dilute acids it loses about 22 per cent, 

 of its phosphorus as orthophosphoric acid, and there remains a prod- 

 uct which appears to be analogous to thyminic acid. It contains 

 one pentose group less than the original molecule and no longer 

 yields guanin and adenin, as these also have been split off. Its 

 formula, determined by deduction of these radicles from the original 

 molecule, would be C^H^N^O^. 



Schmiedeberg's nucleotin-phosphoric acid represents the corre- 

 sponding thyminic acid of salmonucleinic acid. 



The plasminic acid which Kossel and Ascoli obtained from yeast 

 7 



