HABITS OF ANIMALS. 91 



reference to the manner in which they were established ; 

 and this is the proper sphere of investigation in the study 

 of the habits of animals. The behaviour of each kind 

 towards its fellow-beings, and with reference to the con- 

 ditions of existence in which it is placed, constitutes a 

 field of inquiry of the deepest interest, as extensive as it 

 is complicated. When properly investigated, especially 

 within the sphere which constitutes more particularly the 

 essential characteristics of each species of animals and 

 plants, it is likely to afford the most direct evidence of 

 the unexpected independence of organized beings of 

 physical influences, if I mistake not the evidence which I 

 have myself been able to collect. What can be more 

 characteristic of different species of animals, than their 

 motions, their plays, their affections, their sexual relations, 

 their care of their young, the dependence of these upon 

 their parents, their instincts, etc., etc. ; and yet there is 

 nothing in all this which depends in the slightest degree 

 upon the nature or the influence of the physical con- 

 ditions in which they live. Even their organic functions 

 are independent of these conditions to a degree unsus- 

 pected, though this is the sphere of their existence which 

 exhibits the closest connexions with the world around. 



Functions have so long been considered as the test of 

 the character of organs, that it has almost become an 

 axiom in Comparative Anatomy and Physiology, that 

 identical functions presuppose identical organs. Most of 

 our general works upon comparative anatomy are divided 

 into chapters according to this view. And yet there 

 never was a more incorrect principle, leading to more 

 injurious consequences, more generally adopted. That 

 naturalists should not have repudiated it long ago is the 

 more surprising, as every one must have felt again and 



