Chap. IX,] 



CAMPHOR. 



171 



fore, to ascertain whether camphor would render the leaves of 

 Drosera more sensitive to mechanical irritation than they natu- 

 rally are. Six leaves were left in distilled water for 5 m. or 6 rn., 

 and then gently brushed twice or thrice, whilst still under water, 

 with a soft camel-hair brush; but no movement ensued. Nine 



Length of 

 Immersion 



in the 

 Solution of 

 Camphor. 



5 m. 

 5 m. 

 5 m. 



4 m. 30 s. 



4 m. 



4 m. 



4 m. 



3 m. 



3 m. 



Length of Time between the Act of Bmshing 

 and the Inflection of the Tentacles. 



f 3 m. considerable inflection ; 4 m. all I 

 1 the tentacles except 3 or 4 inflected, j 

 6 m. first sign of inflection. 



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

 plain inflection. 



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

 plain ; 4 m. strongly marked. 



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

 plain inflection. 



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

 strongly marked. 



2 m. 30 s. slight inflection ; 3 m. plain ; 

 4 m. well marked. 



2 m. trace of inflection ; 3 m. consider- 

 able, 6 m. strong inflection. 



2 m. trace of inflection ; 3 m. consider- 

 able, 6 m. strong inflection. 



Length of 

 Time between 

 the Immer- 

 sion of the 

 Leaves in the 

 Solution and 

 the Kirsl Sign 

 of the Inflec- 

 tion of the 

 Tentacles. 



8 m. 

 11m. 

 11 m. 30 s. 



7 m. 



6 m. 30 s. 



6 m. 30 s. 



6 m. 30 s. 



5 m. 



5 m. 



leaves, which had been immersed in the above solution of cam- 

 phor for the times stated in the above table, were next brushed only 

 once with the same brush and in the same manner as before; the 

 results are given in the table. My first trials were made by 

 brushing the leaves whilst still immersed in the solution; but it 

 occurred 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 above trials, therefore, each leaf was taken out 

 of the solution, 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 camphor; but this treatment made no dif- 

 ference in the results. 



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 1.5 m. had elapse<l, and 

 two not until a few minutes later. On the other hand, it will be 

 seen in the right-hand column of the table thnt most of t':o leaves 

 subjected to the solution, and which were brushct!, became in- 



