296 chap. xxvii. anaesthetics and geotropism 



Effect of Chloroform on Geotropic Response 



OF Growing Organs 



The following experiments on the action of chloroform 

 were carried out with two different species of plants with 

 the object of bringing out certain characteristic differences. 



Fig. 172. Effect of chloroform on geotropic response, a, en- 

 hancement of geotropic reaction in Echpta; b, prehminary 

 enhancement followed by arrest in Tropaeolum {see text). 



Experiment 159. Seedling of Eclipta. — The epidermis 

 of Eclipta is somewhat impervious to vapour ; hence a 

 relatively small quantity of chloroform vapour is absorbed 

 by the plant. The characteristic effect is seen to be a great 

 enhancement of geotropic reaction which persisted for a 

 considerable length of time (fig. 172, a). The moment of 

 application of the anaesthetic is indicated by an arrow. 



Experiment 160. Petiole of Tropaeolum.- — In the last 

 experiment absorption of a small quantity of chloroform 



