48 



The residue remaining after hydrolysis was washed free of 

 chlorides on ordinary funnels. It was then digested in three 

 Kjeldahl flasks using a total of 30 grams potassium sulfate and 

 360 cc. sulfuric acid. After digestion the material was transferred to 

 a 1000 cc. flask, made to volume, and the nitrogen content deter- 

 mined as described under sphagnum-covered peat. It will be ob- 

 served that the total "humin" nitrogen is determined here instead 

 of being reported in two separate fractions as was done in the 

 case of all other analyses containing mineral soil. 



The combined filtrate and washings from the "humin" precipi- 

 tate were concentrated in the usual manner and made to 200 cc. 

 volume. 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 150 cc. portion was 

 used for the precipitation of the bases, the subsequent procedure 

 being completed as described in the "fibrin from blood" analysis. 

 The barium phosphotungstate precipitate retained 0.0016 gram of 

 nitrogen in Sample I, and 0.0053 gram in Sample II. 



In the second sample the combined filtrate and washings 

 from the phosphotungstic acid precipitate of the bases were brought 

 to near the neutral point with 50 per cent sodium hydroxide and a 

 small amount of acetic acid added at once. After the addition of 

 the acid it seemed possible that the neutral point had not been 

 reached the first time, so more sodium hydroxide was added until 

 the neutral point was just passed and acetic acid again added. The 

 resulting solution was placed in a double-necked distilling flask 

 and an attempt made to concentrate the solution under diminished 

 pressure. Frothing was so intense that it was impossible to effect 

 any concentration. When alcohol was added the distillation con- 

 tinued quietly as long as any alcohol was present, but after that the 

 frothing continued. The mixture behaved like a concentrated soap 

 solution. The solution was finally concentrated in an evaporating 

 dish over a water-bath and the resulting solution made to 300 cc. 

 volume. On shaking the solution frothed very badly. 



The experimental data showing the grams of nitrogen found 

 and the per cent of total nitrogen are given in Table XIV. 



A comparison between these analyses and those of the peat 

 hydrolyzed alone is made in Table XV, the data of the peat hy- 

 drolyzed alone being taken from Table VI, and recalculated from 

 a 15 gram basis to a 10 gram basis. 



