266 LIFE MOVEMENTS IN PLANTS 



plant-chamber at the point marked with an arrow (Fig. 1)6). 

 It will be seen that this induced an almost immediate ac- 

 celeration of the rate, the latent period being less than five 

 seconds. The acceleration continued for two and half 

 minutes ; the accelerated rate then slowed down, became 

 enfeebled, and the growth returned for a short time to the 

 normal as indicated by the horizontal portion at the top of 

 the record ; this proved Hh be the turning point of 

 inversion from acceleration into retardation of growth. The 

 stronger is the concentration of the gas the earlier is the 

 point of inversion. With diluted carbonic acid the accelera- 

 tion may persist for an hour or more. 



EFFECT OF ANAESTHETICS. 



Effect of Ether: Experiment 101. — Dilute vapour of 

 ether is found to induce an acceleration of rate of growth 



Fig. 97. — (a) Effect of ether, acceleration of growth, (6) effect of chloroform 

 preliminary acceleration followed bj* depression. 



which persist for a considerable length of time. This is 

 seen in the upsetting of the balance upwards on the 

 introduction of the vapour (Fig. 97a.). 



