Dogs. 15 



tively enjoys what we abominate ; but as for true delicacy 

 of nerve, which I take to be the power of detecting what 

 is most faint, we cannot presume to the least comparison 

 with him. Every one who has gathered wild plants knows 

 what an immense variety of odours arise from the plants 

 upon the ground — this is the first complication ; next upon 

 that (though we cannot detect it) are traced in all directions 

 different hues of scent laid down by the passage of animals 

 and men — this is the second complication. Well, across 

 these labyrinths of misleading or disturbing odours the dog 

 follows the one scent he cares for at the time (notwith- 

 standing its incessant alteration by mixture) as easily as 

 we should follow a scarlet thread on a green field. If he 

 were only sensitive to the one scent he followed, the mar- 

 vel would be much reduced, but he knows many different 

 odours, and selects amongst them the one that interests 

 him at the time. The only human faculty comparable to 

 this is the perception of delicate tints by the most accom- 

 plished and gifted painters, but here I believe that the 

 intellectual powers of man do much in the education of the 

 eye. No young child could ever colour, though its eye 

 were physically perfect, and colouring power comes only 

 through study, which is always more or less a definitely 

 mental operation. The dog can hardly be said to study 

 scents, though long practice through unnumbered genera- 

 tions may have given refinement and precision to his 

 faculty. 



In speaking of a power of this kind, possessed by 

 another animal, we are liable to mistakes which proceed 

 from our constant reference to our own human impercep- 

 tions. We think, for instance, that the odour of thyme 

 is strong, whilst for us the scent left by an animal in its 

 passage may be so faint as to be imperceptible ; but 



