RESEMBLANCES AMONG ANIMALS 47 



a majority of the most eminent living men of science. 

 New facts, new problems, new difficulties as they 

 arise are accepted, solved or removed by this theory; 

 and its principles are illustrated by the progress and 

 conclusions of every well established branch of human 

 knowledge. It is the object of the present essay to 

 show how it has recently been applied to connect to- 

 gether and explain a variety of curious facts which 

 had long been considered as inexplicable anomalies. 



Importance of the Principle of Utility. 



Perphaps no principle has ever been announced 

 so fertile in results as that which Mr. Darwin so 

 earnestly impresses upon us, and which is indeed a 

 necessary deduction from the theory of Natural Se- 

 lection, namely that none of the definite facts of 

 organic nature, no special organ, no characteristic 

 form or marking, no peculiarities of instinct or of 

 habit, no relations between species or between groups 

 of species can exist, but which must now be or 

 once have been useful to the individuals or the races 

 which possess them. This great principle gives us a 

 clue which we can follow out in the study of many 

 recondite phenomena, and leads us to seek a mean- 

 ing and a purpose of some definite character in 

 minutisB which we should be otherwise almost sure 

 to pass over as insignificant or unimportant. 



Popular Theories of Colour in Animals. 

 The adaptation of the external colouring of animals 



