THE NITROGEN OF PROCESSED FERTILIZERS. 



13 



present in exceedingly small quantities, although the method used in 

 their isolation was subject to no more error than some other of the 

 isolation methods ; this would indicate that the nitrogen of the purine 

 bases makes up but a small percentage of the total nitrogen present 

 in the fertilizer. 



Table IV. — Organic compounds isolated from sample of base goods. 



Compound: Chemical group. 



Source of compound. 



Arginine 



Histidine 



Lysine 



Leucine 



Tyrosine 



Guanine 



Hypoxanthine. 



Diamino acids or 

 hexone bases. 



Monoamino acids. . 



Purine base 



do 



Products of protein hydrolysis by acid treatment of raw materials. 



Plant constituent, or product of hydrolysis of nucleoprotein. 

 Plant constituent, or product of conversion of nucleoprotein-base. 



Purine hases. — It will be noticed that the two purine bases are 

 listed in the table as coming from different sources. It is a well- 

 known fact that the purine bases may exist in plant tissues and plant 

 extracts as such; that is, they are not linked up in more complex 

 compounds in such a way that their peculiar chemical identity is 

 lost. In the garbage which has entered into the manufacture of 

 the fertilizer there were doubtless many sorts of plants or plant 

 remains which contained some or all of the purine bases, and this 

 fact alone would account for the presence of hypoxanthine and 

 guanine in the finished product. This, however, is not the only 

 source of the purine bases. Levene x and his associates have 

 demonstrated that some of the purines enter into the composition 

 of the nucleic acids, which are decomposition products of nucleo- 

 protein and that they may be obtained by a process of hydrolysis 

 from these nucleic acids. Of the four purine bases commonly en- 

 countered, only guanine and adenine have been found to be con- 

 stituent parts of the nucleic acid molecule, it matters not whether 

 the nucleic acid be a decomposition product of animal or plant 

 nucleoproteins. But it has been shown that the two purines found 

 in the nucleic acids may be changed, both by chemical and bio- 

 chemical agencies, into the two other purine bases, xanthine and 

 hypoxanthine, so that these are frequently encountered. Thus by the 

 treatment of guanine with nitrous acid Fischer 2 changed it into 

 xanthine and in the same manner Kossel 3 changed adenine into 

 hypoxanthine. Furthermore, Schittenhelm and Schroter 4 have 

 shown that the putrifactive bacteria, especially the colon bacillus, 



1 Levene and Jacobs, Ber., 44, 746 (1911); Biochem. Zeit., 28, 127 (1910); Levene, Abderhalden's Bio- 

 chem. Arbeitsm., U, 605 (1910); Ibid., V, 489 (1911). 

 2 Liebig's Ann., 215, 309 (1882). 

 3 Zeit. physiol. Chem., 10, 258 (1886). 

 <Zeit. physiol. Chem., 41, 2S4 (1904). 



