190 



in this mass toward the back of the scutellum at a right angle a short 

 distance from the tip; upon removing all the mass from the root tip, which 

 could be done quite easily, this curving- was plainly evident. The root was 

 fixed in a moist atmosphere ou a sheet of cork, with the curved part in a 

 vertical position and the rest of the root in a horizontal position, but no 

 geoti'opic curvature took place. During the time the root was kept in this 

 position it grew almost as rapidly as the control specimens which were 

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

 like mass of tissue on the root-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 liable in the absence of skillful 

 manipulation, upon which experimentation is being conducted. 



