;i2 



THE POPULAR SCIENCE MONTHLY. 



the tips of eleven radicles within the same jars, and five of them became 

 plainly curved away from this side. In the former case the bend was 

 abrupt, as shown in Fig. 15; in the latter a greater length of radicle 



Fia. 16. PiBUM BATivtTM. A radicle extended horizontally in damp air with a little equare of card 

 affixed to the lower side of its tip, causing it to bend upward in opposition to geotropism. 

 The deflection of the radicle after twenty-one hours is shown at A, and of the same radicle after 

 forty-five hours at B, now forming a loop. 



seemed to be affected and the curve was symmetrical, as seen in Fig. 

 16. He says, " It was a striking spectacle, showing the difference in 

 the sensitiveness of the radicle in different parts, to behold in the same 



A. B. 



Pig. 17.- 



.C D. 



-Zka mats : Radicles excited to bend away from the little squares of card attached to 



one side of their tips. 



jar one set of radicles curved away from the squares on their tips, and 

 another set curved toward the squares attached a little higher ujj." 



His experiments upon the radicles of dicotyledons were numerous 

 and varied in every way ; but the seeds of Indian corn were the only 



