' JACQUES LOEB 93 



Experiment I . Leaves and Stems in Moist Air. 



Fresh weight. Dry weight. 

 gm. gm. 



6 detached leaves, at end of experiment 8.242 0.826 



6 sister leaves connected with stem, at end of ex- 

 periment 6 . 476 . 578 



Hence the leaves connected with the base of the stem had given off 

 to the latter about one-third of their dry weight. 



During this time the detached leaves formed roots and tiny shoots 

 in some of their notches while nothing of this kind occurred in the 

 leaves connected with the stems. Instead twelve shoots were formed 

 at the apices of the six stems and the twelve shoots weighed fresh 

 0.528 gm. and dry, 0.068 gm. The inference is that the material for 

 the latter came from the leaves, but apparently more material than this 

 was given ofi" by the leaves to the stems. We have indeed shown in a 

 previous paper that aside from the material for shoot formation the 

 leaf sends material into the stem which may be used for the growth 

 of certain tissues in the stem, resulting in callus formation, geotropic 

 curvature, and increased thickness of the stem.'' 



The experiment was repeated with this difference, that the apices of 

 the leaves dipped into water, while the stem and the rest of the leaves 

 were suspended in moist air. Both sets of leaves were in the same 

 aquarium under equal conditions of temperature, light, and moisture, 

 and both were of equal size and mass at the beginning of the experi- 

 ment. The experiment lasted 18 days. 



Experiment II. Apices of Leaves Dipping in Water; Stems Suspended in Moist Air. 



Fresh weight. Dry weight. 

 gm. gm. 



6 detached leaves, at end of experiment 1 1 . 159 . 791 



6 sister leaves attached to base of stem, at end of 



experiment 4.485 0.388 



Hence the leaves gave off to the stem about 50 per cent of their dry 

 weight. 



This difTerence is only partially accounted for by shoot production 

 in the stem, the total shoot production amounting to 1.166 gm. fresh 

 and 0.111 gm. dry weight. 



Many more experiments than these were made and in some the 

 leaves were weighed both at the beginning and at the end of the 



