m i* z 



imenis r/iTH ..illov/. 



The experiments were made with rooted cuttings 

 of a species of swamp willow growing wild near Baltimore 

 and which is either oalix nigra or a closely related 

 species. The technique was as usual, the soil being loam 

 without sand. Wo injury of any kind was observed in two 

 plants which were treated with nitrogen, normal health 

 and growth continued for 43 days and 2y days respectively. 

 After the first nine days the first plant was supplied 

 with boiled water and every possible precaution was taken 

 to prevent the entry even of traces of oxygen. The sec- 

 ond plant was treated similarly during the entire ex- 

 periment. On the 33rd day the nitrogen was removed 

 from the first plant and carbon dioxide was substituted, 

 care being taken not to admit traces of oxygen. The 

 plant remained on carbon dioxide until the 43d day, when 

 the outlet tubes were opened to the air. This was on 

 August 7, iyi6. IXiring the remainder of the summer the 

 plant continued in this condition, the outlet tubes being 

 open. Water continued to be supplied by the auto- 

 irrigator. Late in October the plant lost its leaves 

 and passed into the resting State. It was kept in the 

 greenhouse during the winter and put out new leaves 

 on April 8, 1917. It is now (April 28, 1917) again 

 under test with nitrogen. At all times the behavior of 

 this plant has been normal and exactly the same as that 



