138 A NATURALIST IN HIMALAYA 



a brido^e ; and the spider that has come to the end of 

 its instinctive round by the completion of its viscid 

 spiral is unable to commence again. Thus the spider 

 is, like Huber's caterpillar, a slave to its own instinct. 

 In a beautiful mechanical rhythm it toils onward in its 

 daily task ; but break that rhythm and the whole chain 

 of action is disturbed, and the only place at which the 

 spider can again take up the thread of its motion is 

 the place at which the rhythm was broken. As in a 

 machine each movement follows another movement in 

 an unalterable sequence, so do the far more complex 

 motions of a spider's life follow one on the other in a 

 long ceaseless rhythm. 



If we learn anything from these experiments, it is 

 how feeble are the mental powers of the Arancus. 

 He who studies for the first time the subtle device of 

 a circular snare is full of wonder at the skill of the 

 contrivance. He who watches for the first time the 

 work of construction is amazed at the ingenuity of 

 the architect. r3ut this is a false impression. There 

 is no skill, no ingenuity in the sense that man would 

 use it. There is little credit to the spider ; at least to 

 the workings of its mind. It is ignorant of all it does. 

 It can neither reflect on its past nor take thought for 

 its future. It must act at any moment in accordance 

 as its instinct tells it. It must fulfil each step in its 

 architecture independent of any choice. It knows not 

 why or how it does it, nor can it do aught else. It 

 cannot go back one inch in its construction. The spider 

 is an automaton. It learns little if anything from 

 experience ; all its knowledge is innate. A definite 

 sequence of events must follow and the spider must 

 obey each step in the sequence. To ponder over 



