Jan. 28, igif 



Nitrogen- A ssimilating Bacteria 



225 



were removed from 'an alfalfa plot, the soil of which was a sandy loam. 

 Previous to transplanting the roots of the young plants were carefully 

 washed in running water and immediately transplanted. The pots 

 were kept well watered, and after two or three days they were removed 

 to the greenhouse. Here they were watered when necessary. Trans- 

 plantations were made on the 27th of June and the experiment termi- 

 nated on the 3d of August. The plants were removed from the pots, 

 the roots carefully washed and examined for the presence of nodules. 

 The results are presented in Table XXXI. 



Table XXXI. — Influence of nitrates in soil on alfalfa nodules and on the reformation of 



nodules 



" Plants died. 



It will be seen in the control pots, where no nitrate was present (ex- 

 cept the small amount normally present in the soil at the beginning of 

 the experiment), that if the nodules were removed, new ones formed. 

 The location of the nodules before their removal was noted, and the 

 new ones were found to occupy the same place. However, when nitrates 

 were added to the soil no new nodules were formed. This statement 

 holds true for both concentrations of all three salts in all experiments. 



