190 



ill this mass toAA'ard the l)ack of the seiitellum at a right angle a short 

 distance from the tip: upon removing all the mass from the root tip. whieh 

 could be done (juite easily, this curving was i)lainl.v evident. The root was 

 fixed in a moist atmosphere on a sheet of cork, with the curved ])art in a 

 vertical position and the rest of the root in a horizontal position. Imt no 

 geoti-opie curvature took place. During the time the root was kejil in this 

 position it grew almost as rapidly as the control specinu'us which were 

 used to estimate the growth. While this accidental occurrence of a cap- 

 like mass of tissue on the rciot-tip showed and verified the same effect 

 on geotropic curvature, as was proved by using the glass caps, neverthe- 

 less it eliminated all the dangers of traumatic effects, to which the glass- 

 cap method might render these parts lial)le in the alisence of skillful 

 manipulation, upon which experimentation is being conducted. 



