368 AUGUSTO BONAZZI 



and distillation into diluted acid (30 cc. H2SO4 in 30 cc. H2O) 

 for thirty minutes served to collect any ammonia resulting from 

 the hydrolysis of the organic substances in the alkahne liquid. 

 The solution was then diluted back to approximately 250 cc. 

 and the nitric nitrogen therein contained determined by reduc- 

 tion and distillation from the alkaline solution in presence of 

 2 grams of Devarda's alloy. The acid solution containing 

 the ammonia resulting from the hydrolysis of the organic matter 

 was then transferred to the Kjeldahl flask containing the 

 residue from the nitrate determination and the solution digested 

 for the determination of organic nitrogen. The solution was 

 digested until excessive frothing had ceased, then 10 grams 

 potassium sulphate were added and digestion continued for one 

 hour after the solution had become bluish-green. It was then 

 distilled through an all-glass apparatus. 



When it was necessary to determine the total nitrogen includ- 

 ing the nitric nitrogen, the procedure developed in this laboratory 

 was adopted (1919). 



The sugar was determined in the solutions by clearing with 

 colloidal iron and the centrifuge, using the clear liquid for the 

 reduction of the FehUng solution as recommended by Shaffer 

 (1914) and titrating the cuprous oxid by means of 0.05 N. potas- 

 sium permanganate after dissolving it in Bertrand's solution. 

 This solution was previously made pink by the use of the per- 

 manganate solution to avoid errors in the determination. 



Thanks are here due to Dr. E. R. Allen for making this work 

 possible and to Mr. B. S. Davisson for his Idnd assistance in 

 carrying through the numerous nitrogen determinations. 



REFERENCES 



Allen 1915 Jour. Ind. Eng. Chem., 7, 521. 



Allen^ 1919 Ann. Missouri Bot. Gardens, 6, 1-44. 



Allen 1920 Ann. Missouri Bot. Gardens, 7, 75-79. 



Beijerink and VanDelden 1902 Centr. f. Bakt. II., 9, 3-43. 



BoNAzzi 1915 Jour. Agr. Res., 4, 225-239. 



BoNAZzi 1919 Jour. Bact., 4, 43-60. 



Cameron and Hurst 1904 Jour. Am. Chem. Soc, 26. 



