46 SPIDERS [CH. 



reader endowed with sufficient patience may observe 

 for himself, gives food for thought. The spider has 

 never seen a cocoon constructed and has no model 

 to work by, and yet it performs with absolute pre- 

 cision all the stages, in their proper succession, of 

 a work which involves quite a number of different 

 spinning operations, nor does the absence of light by 

 which to work trouble it in the slightest. It seems 

 hard to believe that this is not a sign of high in- 

 telligence and that the spider is probably quite 

 unconscious of the object for which it has laboured 

 so long and so aptly. But how otherwise explain 

 this curious fact ? If the eggs are removed the 

 moment they are laid the work is continued precisely 

 as if they w r ere still there. The box is laboriously 

 built round the place where they ought to be, and 

 the spider refuses to budge from the empty casket, 

 though there is no longer any treasure to guard. 



Clearly as the egg-laying time approaches the 

 spider feels an irresistible blind impulse to perform 

 in a definite order certain complicated actions. It is 

 like a machine actuated by an internal spring, and 

 in the spider's case the internal spring is the in- 

 herited nervous mechanism we call instinct, which 

 urges it to actions which it is not in the least neces- 

 sary that it should understand. 



