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. 
Argininc 
Diamine acids or 
hexono bases. 
Monoamino acids. . 
Purine base 
fin 
Histidiiie 
LysiBC 
1 Products of protein hydrolysis by acid treatment of raw materials. 
Leucine 
1 
Tyrosine 
) 
Guanine 
Plant constituent, or product of hydrolysis of nucleoprotein. 
Hypoxanlliinc 
Plant constituent, or product of conversion of nucleoprotein-base. 
Purine bases. — It will be noticed that the two purine bases are 
listed in the table as coming from different sources. It is a v^ell- 
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 pecuhar 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 w^ould account for the presence of hypoxanthine and 
guanine in the finished product. This, however, is not the only 
source of the purine bases. Levene ^ 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 ^ changed it into 
xanthine and in the same manner Kossel ^ changed adenine into 
hypoxanthine. Furthermore, Schittenhelm and Schroter* have 
shown that the putrifactive bacteria, especially the colon bacillus, 
I Levene and Jacobs, Ber., 44, 746 (1911); Biochem. Zeit., 28, 127 (1910); Levene, Abderhalden's Bio- 
chem. Arbeitsm., II, 605 (1910); Ibid., V, 489 (1911). 
a Liebig's Ann., 215, 309 (1882). 
aZelt. physiol. Chem., 10, 258 (1886). 
<Zeit. physiol. Chem., 41, 284 (1904). 
