NITROGEN FROM NITRATES AND AMMONIA. 201 



I have, therefore, made several experiments to decide under 

 what conditions the formation of asparagine is brought about, 

 and whether also its formation takes place in the dark, that 

 is, without the reducing action exerted by light in leaves. For 

 these experiments, I selected such plants as are rich in starch 

 and which form, therefore, under ordinary conditions, but very 

 little asparagine by the decomposition of proteids. 



Barley seeds were distributed in three pots, filled with 

 moist sand, and kept in the dark. After sixteen days the height 

 of the young plants was, on an average 20 cm., but their tips 

 began to dry up gradually. At this time, I subjected the plants of 

 one pot to analysis, while the second pot was treated with a 1 % 

 solution of ammonium chloride, and the third with an equivalent 

 quantity of sodium nitrate. Of each of these solutions, 0.5 litre 

 was administered at three different times. After one week, the 

 growth was found rather insignificant, and the drying at the tips 

 had extended. 



After the sand had been carefully separated by washing, the 

 whole plants were analysed. Not a trace of ammonia could be 

 discovered in them, in spite of their treatment with ammonium 

 chloride. The total nitrogen was determined by Kjeldahl's 

 method, the protein nitrogen by that of Stutzer, and the asparagine 

 by that of Sachsse. 



The result was as follows : — 



Date 15th May 22nd May 



Plants in water, amm. chlor. sod. nitr. 



Total nitrogen 3-512 4-436 4-9 2 5 



Protein nitrogen 2.704 2.126 2.066 



Nitrogen in asparagine' 1 ' 0.656 2.027 °-977 



A very great difference is here seen in the quantity of 

 asparagine, its production being favoured by ammonium salts. 



In a second experiment, young maize of nearly 40 cm. in 

 height was placed with its roots in solutions of sodium nitrate 

 and of ammonium nitrate, both containing 0.1 % of nitrogen, 

 while the control plants were placed in distilled water. After 



(1) No especial nllention was paid here to the other amido-compounds, which 

 evidently must have been present in all three cases. 



