1 862.] INSECTIVOROUS PLANTS. 321 



fluid from cell to cell, for I can see the rate of absorption, 

 which though quick, is far slower, and in Dionsea the trans- 

 mission is instantaneous ; analogy from animals would point 

 to transmission through nervous matter. Reflecting on 

 the rapid power of absorption in the glands, the extreme 

 sensibility of the whole organ, and the conspicuous move- 

 ment caused by varied stimulants, I have tried a number of 



substances which are not caustic or corrosive, 



but most of which are known to have a remarkable action 

 on the nervous matter of animals. You will see the results 

 in the enclosed paper. As the nervous matter of different 

 animals are differently acted on by the same poisons, one 

 would not expect the same action on plants and animals ; 

 only, if plants have diffused nervous matter, some degree of 

 analogous action. And this is partially the case. Consider- 

 ing these experiments, together with the previously made 

 remarks on the functions of the parts, I cannot avoid the 

 conclusion, that Drosera possesses matter at least in some 

 degree analogous in constitution and function to nervous 

 matter. Now do tell me what you think, as far as you can 

 judge from my abstract ; of course many more experiments 

 would have to be tried ; but in former years I tried on 

 the whole leaf, instead of on separate glands, a number of 

 innocuous * substances, such as sugar, gum, starch, &c, and 

 they produced no effect. Your opinion will aid me in decid- 

 ing some future year in going on with this subject. I should 

 not have thought it worth attempting, but I had nothing on 

 earth to do. 



My dear Hooker, yours very sincerely, 



Ch. Darwin. 



P.S. — We return home on Monday 28th. Thank Heaven ! 



* This line of investigation made Professor Oliver, and in reference 



him wish for information on the to the result wrote to Hooker : 



action of poisons on plants ; as in " Pray thank Oliver heartily for his 



many other cases he applied to heap of references on poisons." 



VOL. III. Y 



