JACQUES LOEB 



655 



the process of flowing into the stem. The two sister leaves without 

 stems have formed shoots and roots in their notches, one at the base 

 and the other on one side. The reddish pigment is collected near the 



Fig. 2. Two sister leaves suspended entirely in air. The stippling indicates 

 the reddish pigment. In the leaf to the left which is connected with a piece of 

 stem the pigment flows into the axillary shoot of the stem, into the petiole, and is 

 collected in the upper part of the leaf nearest the petiole. In the sister leaf with- 

 out stem it collects near the place where the new shoots are formed and in the 

 new shoots. Duration of experiment, Feb. 17 to Apr. 5. 



newly formed shoots and on its. way to these organs. These obser- 

 vations support the assumption that the inhibitory effect of the piece 

 of stem on shoot formation in a leaf is due to the fact that the material 

 available for shoot formation in the leaf flows naturally into the 



