36 



Kutschpr« for the separation of certain bodies resulting from the 

 decomposition of protein with acids barium hydrate is used in this 

 way. The amounts of nitrogen in the barium precipitate hy this 

 method when working on protein })odies is small, and the authors 

 speak of it as hunuis nitrogen. Considering the small amounts involved 

 and the fact that the method was applied in the study of other bodies, 

 the autiiors are proba])ly justified in using this vague term. In the 

 case of a soil solution, however, containing 5(J per cent of so-called 

 humus nitrogen, such designation is very unsatisfactory since it con- 

 veys little or no information as to the nature of the body or bodies so 

 named. 



Along this line, then, a study of the nature of the nitrogen com- 

 pound or compounds contained in the magnesia precipitate from acid 

 solutions is the present stage of the work. 



Approaching the nitrogen problem from another standpoint, some 

 work has been done which may be outlined as follows: 



All Hawaiian soils rich in nitrogen which have so far been examined 

 give on dry distillation an alkaline distillate containing ammonia. In 

 many cases the smell of ammonia on simple ignition in an open 

 crucible is very pronounced. 



The alkalinity of this distillate has been determined in a number of 

 cases. The distillation was carried on first at a gentle heat and finally 

 raised to a red heat, the distillate being collected in a known volume 

 of standard acid. In the case of the Pohakea soil, assuming the alka- 

 linity to be due to ammonia, it was found to be equivalent to 0.168 

 per cent nitrogen. The total nitrogen in the distillate was 0.145 

 per cent. It is interesting at this point to compare the ammonia 

 actually in the soil as found by distillation with magnesia, 0.007 per 

 cent, and also the ammonia derived from the acid solution, 0.119 per 

 cent. 



In addition to ammonia this distillate contains pyridin and some of 

 its homologues not yet identified. The proportion of the alkalinity 

 due to ammonia and that due to the pyridins has of course not yet 

 been determined. 



Generally speaking, pyridin is formed on the dry distillation of 

 nitrogenous carbon compounds and as derived in this way is found in 

 coal tar, tar from shales, peat, and in bone oil. Richter^^ says: "Its 

 presence in bone oil is due to the reciprocal action of fats and 

 substances containing ammonia (albumins), the acrolein arising from 

 the first probably condensing with the ammonia to form pyridins. 

 Bone glue free from fats does not yield pyridin bases, but mainly 

 pyrrols." 



«Ztschr. Physiol. Chem., 30 (1900), p. 166. 

 b Organic Chemistry, vol. 11, p. 528. 



