Rev. P. Keith on the Susceptibilities of Lhmig Structures. 255 



little air-bubbles, and suddenly expanding when they reach 

 the surface, where they float about in great numbers, anions 

 the female blossoms, and often cling to them in clusters, so as 

 to cover them entirely; thus bringing the stamens and pistils 

 into immediate contact, and giving the anthers an opportunity 

 of discharging their pollen over the stigma. When this ope- 

 ration has been performed, the now uncoiled stalk of the fe- 

 male plant begins again to resume its original and spiral form, 

 and gradually sinks down, as it gradually rose, to ripen its 

 fruit at the bottom of the water. 



Such are the indications which are thought to demonstrate 

 the existence of vegetable volition, desire, and design. Yet 

 the direction of the root proves only the agency of a sort of 

 physical, or chemical attraction between its extreme fibrils 

 and the soil; and the direction of the stem proves only the 

 agency of a similar attraction between the young and tender 

 shoot and the water, like the attraction of the magnet for iron, 

 or of a rubbed cylinder of glass for a tuft of thisde-down. 

 At the best it is but a vegetative loco-motion. The shoot does 

 not walk towards the water, it only grows towards it. — Does 

 it seem strange that the water should act on the tender shoot 

 at the distance of six inches ? — Let it be remembered that 

 there are many much more wonderful cases of distant action 

 in nature, that do not at all involve the idea of volition. The 

 agency of gravitation extends even to the heavenly bodies, 

 binding and uniting them together in one entire and connected 

 whole. The attraction of the sun keeps the earth in its orbit. 

 The attraction of the moon causes the tides of the ocean*. — 

 The phaenomenon of the self-moving leaves of Hcdysarum 

 gyrans participates more of the character of animal sponta- 

 neit}' than any other movement hitherto observed in vege- 

 tables ; and yet it is but a single fact, and cannot establish a 

 position that must rest on a copious induction 'of particu- 

 lars. How is it that its movements never intermit? — In this 

 they resemble rather those movements of the animal system 

 that are wholly involuntary, for such have no intermissions; 

 whereas the movements that proceed from volition soon begin 



* It appears to us that the elongation of the shoot of the cucumber to- 

 wards the vessel of water, does not [)resent even so much as a case of distant 

 action, in the sense in which that term is used above. Tiie water will neces- 

 sarily diffuse around itselfa sphere of vapour, which will extend to the shoot, 

 and of course promote its growth on that side with which it is principally in 

 contact, that is on the side towards the water. 'J'liis growth will proceed 

 in the direction in which the vapour is supplied, that being the direction in 

 which the greatest quantity of moisture will be afforded to the plant. The 

 direction in which the vapour is i^iipplied will be that of a radius from the 

 water to the plant. Hence the shoot, as it appears to us, must necessarily 

 elongate in the direction of the vessel, and finally reach the water. — Edit. 



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