186 THE PROTEIN SUBSTANCES. 



The somewhat different results found on the elementary analysis of these 

 two acids do not seem to be of very great importance and we have strong 

 evidence for the identity of these acids. OSBORNE and his collaborators 

 found the formula C^HeiNieP^si for triticonucleic acid. 



The plant nucleic acids have the general reactions of the complex 

 nucleic acids but can be precipitated by an excess of acetic acid. They 

 are dextro-rotatory. 



In regard to their preparation we refer to the works of KOSSEL, OSBORNE 

 and HARRIS and to LEVENE and co-workers. 1 



Plasminic acid is an acid which was prepared by ASCOLI and KOSSEL 2 by 

 the action of alkali upon yeast. It contains iron, and is soluble in very dilute 

 hydrochloric acid (1 p. m.). It is still a question whether it is a mixture or a 

 chemical individual. 



2. Purine Bases. 



The cleavage products obtained from the nucleic acids, the nudein 

 bases, which are also called alloxuric bases by KOSSEL and KRUGER, are 

 members of the larger group of purines, to which also belongs the uric 

 acid which is a substance occurring in the animal body. The constitu- 

 tion of these bodies has been explained by E. FiscHER, 3 and he has 

 prepared many of the bodies synthetically. They can all be derived from 

 the synthetically prepared purine, CsHiN^ which has the formula given 

 below and which may be considered as a combination of a pyrimidine 

 ring with an imidazole ring. 



HC NH 

 HC C NH V HC CH || >CH 



II II >CH || || HC N 



N C W N-CH 



Purine Pyrimidine Imidazole 



The different purine bodies are derived therefrom by the substitution of the 

 various hydrogen atoms by hydroxyl, amide, or alkyl groups. In order to signify 

 the different positions of substitution FISCHER has proposed to number the nine 

 members of the purine nucleus in the following way : 



I I 

 2C 5C N7 



C8. 



3N C N9 

 4 



1 See footnote 2, p. 179, and footnote 3 and 4, p. 185. 



2 Ascoli, Zeitschr. f. physiol. Chem., 28. 



3 See E. Fischer, Untersuchungen in der Puringruppe (1882-1906) Berlin, 1907. 



