254 Rev. P. Keith on the Susceptibilities of Living Structures. 



finding that plants do not furnish us with any satisfactory 

 symptoms of sensation in their ordinary movements, we can- 

 not concede it to them in a particular case, merely to help 

 out the defective proof of their being endowed with instinct. 



Lastly, the advocates of the doctrine in question regard cer- 

 tain vegetable movements as affording indubitable indications, 

 not only of sensation and perception, but of volition, desire, 

 and design*. — 1st. When the roots of vegetables are lodged 

 in the earth, they are found to have the power of protruding 

 their fibres in the direction of the best soil, and of changing 

 that direction when they meet with an obstacle which ihey 

 cannot penetrate, or cannot remove. — 2ndly. If a vessel filled 

 with water is placed at any point within six inches of the stem 

 of a growing cucumber, the shoot will elongate in the direc- 

 tion of the vessel, and follow it till it reaches the water. — 

 3rdly. The leaves of Hedi/sarum gp-ans, a plant that grows 

 on the banks of the Ganges, are all of them in perpetual 

 motion up and down, sometimes equably, and sometimes by 

 jerks. If their movement is stopt by grasping them in the 

 hand, they resume it when the hand is removed, and quicken 

 it as if to make up for lost time. It does not depend upon 

 the application of any external stimulus, for it takes place by 

 night and by day, in the dark and in the light, and requires 

 only a very warm and fine day to be effected in the best style. 

 — 4thly. The water-lily does not put forth its blossom till it 

 reaches the surface of the stream in which it grows, be it shal- 

 low or be it deep. — 5thly, At the period of the maturity of 

 the flower the stigma of some plants opens as if to receive the 

 pollen, or becomes moistened with an exuding and viscous 

 fluid, as if to attract and detain it. The style of Gloriosa 

 superba bends itself towards the stamens, and the stamens of 

 the genus Saxifraga bend themselves down to the stigma, in 

 obedience, as it has been supposed, to a sort of amorous de- 

 sire. But the most remarkable example of this kind is that 

 of Valisneria spiralis, a plant that grows in the ditches of 

 Italy. It is well described and figured by Michelif, and is 

 dioecious, pi'oducing its fertile flowers on a long and slender 

 stalk, twisted spirally like a corkscrew, which uncoiling of its 

 own accord, about the time of the opening of the blossom, 

 elevates the flowers to the surface of the water and leaves 

 them to expand in the open air. The barren flowers are pro- 

 duced in great numbers upon short upright stalks issuing from 

 a different root, from which they detach themselves, about 

 the time of the expansion of the blossoms, mounting up like 



* Darwin's Zoon. vol. i. Sect. 13. f Nov. Gen. Plant, p. 12. tab. x. 



little 



