LBCT. VI 1.] ANATOMY OF STEMS. 375 



even so far as to believe that it furnishes "the 

 " power of motion, as well as of sensation to the 

 " various parts of the vegetable system *." Hales 

 and Linnaeus also regarded it as the seat of the 

 vital energy of the plant -f~ ; and Mr. Lindsay, of 

 Jamaica, " thought he demonstrated the medulla 

 " in the leaf-stalk of the Mimosa puclica, or Sen- 

 " sitive Plant, to be the seat of irritability ;" nor 

 " can I," says Sir J. E. Smith, " see any thing 

 " to invalidate the opinion J." It would, never- 

 theless, be no difficult task to prove the unte- 

 nable nature of these doctrines, were they not com- 

 pletely destroyed by the experiment of Mr. Knight, 

 who abstracted more than an inch of the pith from 

 the shoot of a vine, above and below a leaf and 

 bud ; both of which, " with the lateral shoot an- 

 " nexed, continued to live, and did not appear to 

 " suffer much inconvenience ; but faded a little 

 " when the sun shone strongly upon them ." Now 

 the life of the shoot, even admitting with Darwin, 

 for the sake of argument, that each bud has a sen- 



* Phytologia, xviii. 2, 13. 



f Linnaeus, like Darwin, compared it to the spinal marrow. 



J Introd. to phys. and syst. Bot. chap. vii. 



Phil. Trans. 1801, p. 338. 



Mr. Keith gives a quotation from Theophrastus to show 

 " that this experiment had been performed, and the result as- 

 " certained," even in the time of that naturalist. System of 

 phys. Bot. vol. ii. p. 211. 



B B 4 



