I'(j4j ON THE DIRECTION OF THE GROWTH OF ROOTS. 



insufficient to explain the preceding phenomena, unless seedling plants 

 be admitted to possess more extensive intellectual powers, than are given 

 to the offspring of the most acute animal. A young wild-duck or par- 

 tridge, when it first sees the insect upon which nature intends it to feed, 

 instinctively pursues and catches it ; but nature has given to the young 

 bird an appropriate organization. The plant, on the contrary, if it could 

 feel and perceive the objects of its wants, and will the possession of them, 

 has still to contrive and form the organ by which these are to be ap- 

 proached. The writers who have contended for the existence of sensa- 

 tion in plants, appear to have been sensible of the preceding and other 

 obstacles, and have all betrayed the weakness of their hypothesis, in 

 adducing a few facts only which are favourable to it, and waiving wholly 

 the investigation of all others. 



In the description of the preceding experiments, I fear that I have 

 been tediously minute ; but as I have selected a few facts only from a 

 great number, which I could have adduced, I was anxious to give as 

 accurate and distinct a view of those I stated, as possible. 



XIV. ON THE MOTIONS OF THE TENDRILS OF PLANTS. 

 [Read before the ROYAL SOCIETY, May 4th, 1812.] 



THE motions of the tendrils of plants, and the efforts they apparently 

 make to approach and attach themselves to contiguous objects, have 

 been supposed by many naturalists to originate in some degrees of 

 sensation and perception : and though other naturalists have rejected 

 this hypothesis, few, or no experiments have been made by them to 

 ascertain with what propriety the various motions of tendrils, of different 

 kinds, can be attributed to peculiarity of organisation, and the operation 

 of external causes. I was consequently induced, during the last summer, 

 to employ a considerable portion of time to watch the motions of the 

 tendrils of different species of plants ; and I have now the pleasure to 

 address to you an account of the observations I was enabled to make. 



The plants selected were, the Virginia creeper (the Ampelopsis quin- 

 quefolia of Michaux,) the ivy, and the common vine and pea. 



A plant of the ampelopsis, which grew in a garden pot, was removed 

 to a forcing-house in the end of May, and a single shoot from it was 

 made to grow perpendicularly upwards, by being supported in that 

 position by a very slender bar of wocd, to which it was bound. The 



