THE NITEOGEN OF PEOCESSED FEETILIZEES. 17 



obtained by difference from the non-amino N and the arginine N 

 according to formula (1) on page 7, it is evident that if there are pre- 

 cipitated by the phosphotungstic acid compounds which contain non- 

 amino N other than arginine and histidine, such nitrogen will be 

 classed as histidine N, because the arginine N is determined directly. 



A comparison of the results for histidine shows that there is 2.88 

 per cent less N calculated as histidine in the hydrochloric acid ex- 

 tract than in the water extract and at the same time there is an 

 increase in lysine N in the hydrochloric acid extract amounting to 

 2.20 per cent. This shows that by the hydrolysis with hydrochloric 

 acid some substance which reacted as though it contained non- 

 amino N has been decomposed with the formation of an almost cor- 

 responding amount of amino N. Here again the indications are that 

 this substance is of the class of compounds related to the proteins. 



This is further borne out by the fact that in the monoamino acid 

 fraction the nitrogen listed as amino N has increased in per cent 0.17 

 and the nitrogen as non-amino N has increased in per cent 1.17 by 

 hydrolysis with hydrochloric acid. 



A comparison of the figures for humin N shows an increase of 2.66 

 in the hydrochloric acid extract, but since the nature of the com- 

 pounds in which this class of nitrogen exists is not understood no inter- 

 pretation can be given to this figure. 



Proteoses. — In order to prove the presence of some intermediate 

 product of protein hydrolysis, which is thus indicated by analytical 

 methods, an aqueous solution of about 2.5 pounds of base goods was 

 made and the diamino acids were precipitated with phosphotungstic 

 acid, in the presence of 5 per cent sulphuric acid. The precipitate 

 which formed was allowed to stand over night and after filtering off 

 it was washed well with 5 per cent sulphuric acid. The precipitate 

 was dissolved in sodium hydroxide, the phosphotungstic acid precipi- 

 tated by adding barium hydroxide solution, and after filtering the 

 excess of barium was removed by adding sulphuric acid until a neu- 

 tral reaction was obtained. Portions of this solution were tested for 

 peptones, proteoses, etc., with the following results; The biuret test 

 was positive; a precipitate was obtained on saturation of the solution 

 with ammonium sulphate, or with sodium chloride; when the nitrate 

 from the latter solution was treated with acetic acid a cloudy precipi- 

 tate developed. Precipitates were also obtained with sulphuric acid, 

 hydrochloric acid, phosphomolybdic acid and with phosphotungstic 

 acid. A precipitate was formed on the addition of alcohol to the 

 solution. This precipitate was filtered off, dissolved in dilute alkali, 

 and on addition of very dilute copper sulphate solution the biuret 

 reaction was again obtained. These reactions are those which are 

 given by proteoses and by the proteins and confirm the conclusions 



