NITROGENOUS METABOLISM 



467 



Analytical examples. The following tables constructed by Schulze show the 

 extent to which asparagin may accumulate ', and also the increase in the amides and 

 certain other nitrogenous substances which take place as the proteids decrease. 

 Plants grown in darkness were harvested after eight to thirteen days ; in the first 

 case the hypocotyl was from 2-2-5 cm. long, in the second 7-9 cm. 



The following are the results obtained by Prianischnikow 

 Vicia sativa germinated in darkness. 



with seeds of 



Further details concerning the methods employed, &c. can be obtained by 

 reference to the works quoted in Sect. 79. On microchemical methods, cf. 

 Zimmermann, Mikrotechnik. These were first systematically employed by Pfeffer 

 in the study of asparagin (1872). No deposition of asparagin occurs in a living 

 cell even when the latter contains more of it than the water of the cell-sap 

 can dissolve, but it is doubtful whether this is due to the formation of an over- 

 saturated solution 3 , or to the combination of the asparagin with some other 

 substance. Even when the total amount of water present may just be sufficient 



1 E. Schulze, Landw. Jahrb., 1876, Bd. v, p. 848. Detailed analyses of the seeds of Lupinus 

 in Versuchsst., 1891, Bd. xxxix, p. 294. 



a Prianischnikow, Versuchsst., 1896, Bd. XLVI, p. 467. 



3 On over-saturated solutions, cf. Ostwald, Lehrb. d. allgem. Chemie, 2. Aufl., 1891, Bd. I, 

 p. 1039; Zeitschr. f. physik. Chemie, 1897, Bd. xxn, p. 289. 



H h 2 



