394 CHAP. XXXIV. THE MECHANISIM OF THE TWINING STEM 



an increase in the rate of torsion ; while depression of ascent, 

 as well as plasmolytic withdrawal of water, induces retarda- 

 tion of the rate or reversal of the direction of torsion. 



Rise of temperature up to an optimum induces an 

 enhancement of the rate of torsion ; lowering of tempera- 

 ture brings about a depression of the rate, or an arrest of 

 the movement. 



At the critical temperature of about 60° C. there is a 

 reversal of the direction of torsion, which is the spasm of 

 death. 



A feeble dose of chloroform enhances the rate, but a 

 strong dose causes arrest or reversal. 



Ether in moderate dose greatly enhances the rate of 

 torsional growth. 



