1 84 Sensibility of Vegetables. 



parts of the same object, and so producing double vision. It 

 may be concluded that smallness of the field of vision, want 

 of mobility in the organ, plurality of simple eyes, and diverg- 

 ence from each other, are conditions necessarily combined. 



In the scorpions, the two great simple eyes diverge from 

 each other at an angle of even 90°. In the same animals, these 

 divergent eyes are still farther insulated by an interposed 

 ridge of integuments : they correspond to different parts of 

 the animal's field of vision, and probably both eyes never see 

 at one time the same object. 



In the spiders, the simple eyes are always arranged in a 

 line, forming an arch in the skin, and they diverge at different 

 angles. Being of very different magnitudes, even in the same 

 individual, it may be inferred that they must also differ, not 

 only with respect to the extent of the visual field, but likewise 

 as it regards the distance to which distinct vision reaches. The 

 great and very divergent eyes of scorpions possess, undoubt- 

 edly, a more extensive visual field, and see also to a greater 

 distance, than the smaller eyes of these animals ; which, being 

 but little divergent, like the. eyes of most of the spiders, are 

 probably distinguished, on the other hand, by the smallness 

 of the field of vision, and by being myopic. It may be readily 

 conceived, that if the distance to which the power of seeing 

 extends differs in different eyes, a partial crossing of the visual 

 fields will induce no marked confusion of sight, provided that 

 the vision be distinct only in that eye within whose range of 

 power the objects are situated. 



{To be continued.^ 



Art. VI. On the Sensibility of Vegetables. By T. E. L. 



Sir, 

 It is a well-known fact that vegetables possess a physical, 

 though, perhaps, not a rational sensibility, and that they can, 

 and indeed do, avoid what is injurious to them, though 

 probably not immediately ; but the power which is employed, 

 and enables them to withdraw out of the way of danger, is 

 still a secret. Of this the Mimosa pudica, or sensitive plant, 

 is an instance well known to every body ; for, if its leaves be 

 touched ever so slightly, they close and draw back, as if they 

 would shrink from the approach of danger. The leaves of 

 some plants, however, act spontaneously, without any visible 

 or material agency, of which the JTedysarum gyrans is a 

 striking instance, requiring only a warm atmosphere to 

 perform in perfection. Each of the leaves is ternate, and 



