134 ANIMALS AT WORK AND PL A Y 



their eyes, and will walk over a dead bird while their 

 brain is intent on discovering its place by scent alone, 

 Weasels, when hunting, will run up to a human 

 being who imitates the squeak of a rabbit and peer 

 up at him to discover where the sound comes from. 

 The smallness of the eye limits its powers ; just as 

 the best telescope has usually the largest object-glass, 

 so the largest eye will probably be the best organ of 

 sight ; and in the absence of any extraordinary develop- 

 ments in the size of the organ itself in animals, their 

 power of vision must, in the absence of evidence to 

 the contrary, be supposed to be proportionately 

 limited. 



