210 



DKOSERA ROTUNDIFOLIA. 



Chap. IX. 



wished, therefore, to ascertain whether camphor would render the 

 leaves of Drosera more sensitive to mechanical irritation than 

 they naturally are. Six leaves were left in distilled water for 

 5 m. or 6 m., and then gently brushed twice or thrice, whilst still 

 under water, with a soft camel-hair brush ; but no movement 

 ensued. Nine leaves, which had been immersed in the above 

 solution of camphor for the times stated in the following 

 table, were next brushed only once with the same brush and in 

 the same manner as before ; the results are given in the table. 

 ]\Iy first trials were made by brushing the leaves whilst still 

 immersed in the solution ; but it occiu'red to me that the viscid 

 secretion round the glands would thus be removed, and the 

 camphor might act more effectually on them. In all the 

 following trials, therefore, each leaf was taken out of the solu- 

 tion, waved for about 15 s. in water, then placed in fresh water 

 and brushed, so that the brushing would not allow the freer 

 access of the camj)hor ; but this treatment made no difference 

 in the results. 



30 



("3 m. considerable inflection ; 4 m. all)' 

 \ the tentacles except 3 or 4 inflected./ 

 G m. first sign of inflection. 

 6 m. 30 s. slight inflection ; 7 m. 30 s.V 



plain inflection. / 



2 m. 30 s. a trace of inflection ; 3 m.V 



plain ; 4 m. strongly marked. / 

 2 m. 30 s. a trace of inflection; 3 m.V 



plain inflection. j, 



2 m. 30 s. decided inflection ; 3 m. 30 s.'i 



strongly marked. / 



2 ra. 30 s. slight inflection; 3 mA 



plain ; 4 m. well marked. / 



2 m. trace of inflection ; 3 m. con-\ 



siderable, 6 m. strong inflection. J 

 2 m. trace of inflection ; 3 m. con- 1 



siderable, G m. strong inflection, f 



8 m. 

 11 m. 

 11m. 30 s. 



7 m. 



G m. 30 s. 



G m. 30 s. 



G m.30 s. 



Other leaves were left in the solution without being brushed ; 

 one of these first showed a trace of inflection after 11 m.; a 

 second after 12 m.; five were not inflected until 15 m. had 



