Chapter I. 



SENSE OF TOUCH. 



Though we may entertain considerable doubts of the 

 accuracy of the poet's observation, when he says the 

 spider 



' Lives in each thread, and feels along the line, ' 



there can be no question that the legs of spiders pos- 

 sess considerable powers of touch, so far as resistance 

 is concerned ; for in constructing, and still more in 

 repairing, their webs, they never advance a step with- 

 out making sure of the strength of what has been 

 already completed. They are not even always con- 

 tent with pulling the threads for this purpose^ but 

 frequently let themselves down like a plummet from 

 the thread whose strength they wish to try, and bob 

 backwards and forwards with the whole weight of 

 the body. But that the acuteness with which the 

 motion of the threads is felt, when a fly is caught in 

 the net, chiefly governs the motions of the spider in 

 seizing it, we doubt for several reasons. Spiders, for 

 example, are furnished with not less than six, though 

 more commonly with eight, eyes of sparkling bril- 

 liancy, and placed in a very prominent situation ; and 

 these we should be apt to look upon as in part su- 

 perfluous, were the sense of touch so exquisite as is 

 generally believed. We have tried numerous experi- 

 ments by moving and vibrating the lines of the webs 

 of many species, so as to imitate as nearly as possible 

 the entrapment of a fly ; but in no case have we 



