THE .ACQUISITION OF ATMOSPHERIC NITROGEN. I25 



season, but the following year the plant from the inoculated pot 

 made a vigorous growth and branched freely, while uninoculated 

 plants were without branches and in a famished condition. 



Experiments by Breal,* Frank,f and others indicate that 

 some other non-leguminous crops — including oats, barley, rape, 

 spurry and cresses — may utilize a certain amount of atmospheric 

 nitrogen. In Breal's experiments, cress seeds were germinated 

 on moist filter paper and then transferred to flower pots contain- 

 ing sand. The pots were moistened with a nutritive solution 

 containing all the essential elements of plant food except nitro- 

 gen. The plants developed slowly at first but afterward made 

 normal growth and produced seeds. A determination of the 

 amount of nitrogen in sand at the beginning and the end of 

 the experiment, as also that in the water used and in the plants, 

 was made. It was found that the plants produced, contained 

 much more nitrogen than the seed and the water used. 



That the gain above noted was due to micro-organisms was 

 shown by a duplicate lot in which both the sand and the seeds 

 used were sterilized. "The plants in sterilized soil grew nor- 

 mally at first but after reaching a height of about 0.14 meter 

 produced a few imperfect seeds and began to languish." 



From the data presented it was concluded: 



1. "A soil very poor in nitrogenous matter planted with 

 cresses (Breal) or with various phanerogamous or cryptoga- 

 mous plants (Frank) is capable of bringing these plants to 

 maturity. 



2. "The nitrogen used is not entirely derived from the soil, 

 since it appears that in some cases the soil is enriched instead of 

 impoveris'hed by the gain of the plant, and in cases where loss 

 does occur it is overbalanced by the gain by the plant."t 



In a resume of his experiments in i8o,2§ Frank referred to two 

 experiments with non-leguminous phanerogams — mustard and 

 potato. The results were as follows:^ 



Sinapis alba (4 plants) — grams of nitrogen in seed 0.0012; in 

 crop, 0.0043. 



*Ann. Agronom. IS (1S92), No 8, pp. 269-379. 



fDeut. Landw. Pre9se, 1891, p. 779. 



^Abstract of Breal's paper, Ex. Sta. Record IV, 376. 



§Bot. Ztg. 51: 150 et. seq. 



ITCited by Russell, Bot. Gaz. XIX, 286. 



