CH. X] EXPERIMENTS. 259 



the total NO observed in (a) : the difference is NO from 

 Nitrate. 



[See Sutton, p. 366.] 



(1 c.c. of NO (at and 760 mm.) 



= -00170 grs. N 2 3 or "00242 grs. N 2 O 5 ). 



Ammonia and other nitrogenous compounds will not 

 seriously interfere with these reactions. 



For estimation of ammonia present in aqueous solution 

 see Dragendorff, 97, p. 81. 



Experiments on nitrogenous Metabolism. 



Qualitative. 



Make an aqueous extract of young plants of Onobrychis 

 sativa 1 which have been grown in the dark and extract the 

 residue (after exhaustion with water) with 2 p.c. NaOH 

 (see p. 245). 



Examine the NaOH extract for proteids insoluble in 

 water. 



Examine the aqueous extract for soluble proteids, 

 peptones and albumoses, amides. 



Examine another portion of the aqueous extract for 

 ammonia, nitrates, and nitrites. 



Quantitative. 



Compare the amounts of insoluble proteids, soluble 

 proteids, peptones and albumoses (if qualitative examina- 



1 The seeds should be put to germinate 8 10 weeks before the 

 material for these experiments is required. 



172 



