39 



tion from the humin precipitate had a characteristic light blue 

 color in each case. Duplicate Kjeldahl determinations were made 

 on 25 cc. portions of this solution and the results listed as total- 

 nitrogen-in-the-filtrate-from-humin. The remaining 200 cc. solu- 

 tion was used for the precipitation of the bases and the subsequent 

 analysis, but of course the results were calculated on the basis of 

 the total volume. The total nitrogen belonging to the aliquot an- 

 alyzed was determined by adding the nitrogen obtained as am- 

 monia, humin, and total-nitrogen-in-the-filtrate-from-humin to the 

 insoluble-humin-nitrogen-in-the-soil. The filtrate-from-the-bases 

 was made to 250 cc. volume. Twenty-five grams of phosphotungstic 

 acid was used for the precipitation of the bases. The nitrogen 

 retained by the barium phosphotungstate was 0.0022 gram for 

 Sample I and 0.0020 gram for Sample II. 



The experimental data showing the grams of nitrogen found 

 a-nd per cent of total nitrogen are given in Table II. 



Table II. Nitrogen distribution *in tJyree grams of Merck's "fibrin 

 from blood" hydrolyzed in the presence of 100 grams of ignited subsoil. 



Grams nitrogen Per cent of total nitrogen 



iFrom data of Gortner (1916 c). 



Table III shows a comparison of these analyses with other 

 analysis of the same sample of fibrin hydrolyzed alone, and in the 

 presence of three times its weight of cellulose (data of Gortner 

 1916 c). 



Differences .between these analyses, together with differences 

 between duplicates in each series of analysis, and data showing 

 "maximum" and "average" experimental differences to be expected 

 are given in Table IV. 



These comparisons will be considered in detail under "Dis- 

 cussion" in the latter part of this paper. 



