ON THE 



SENSES, INSTINCTS. AND INTELLIGENCE 



OF 



ANIMALS. 



CHAPTER I. 



INTEODUCTOEY EEMAEKS. 



The organs of sense may be said to be the windows 

 through which we look out into the world, and it has 

 always been to my mind one of the most interesting 

 problems of natural history, to consider in what manner 

 external objects affect other animals, how far their 

 perceptions resemble ours, whether they have sensations 

 which we do not possess, and how we ourselves arrive 

 at our own perceptions. 



I propose to dweli in the present work especially on 

 the senses of insectf=, partly because my own observa- 

 tions have been made principally on them, and partly 

 because their senses have, perhaps, been on the whole 

 more thoroughly and successfully studied than those 

 of the other lower animals ; which again arises from 

 the fact that no group offers more favouiable oppor- 

 tunities for the study of these organs. The subject is 

 no less vast than difficult, and I do not pretend in any 

 way to give a complete view of the whole question, 



