EVOLUTION OF THE COLORS OF BIRDS. 41 



potent, that the additional hypothesis of use-inheritance 

 seems perfectly superfluous. Where intelligence is not 

 highly A'alued and carefully promoted by selection, the 

 intelligence derivable from association with man does 

 not appear to be inherited. Lap-dogs, for instance, are 

 often remarkably stupid." It seems to me that Ball 

 does not establish his point- in this instance. To be 

 sure, it might be claimed that thoroughbred dogs had 

 attained their intelligence through selection alone 

 (although this I should be inclined to question), but 

 such dogs are generally, if not universally, bred with 

 one especial end in view, either speed, hunting qual- 

 ities, fighting qualities, beauty or eccentricty; but how 

 often are they bred for intelligence? Moreover the 

 most intelligent dogs are not infrequently curs. A large 

 number of the most remarkable stories of canine sagac- 

 ity are told of animals without a pedigree. But these 

 •dogs have not been selected at all, for the most part. 

 What is the fate of a large litter of puppies of a cur? A 

 part of them are generally destroyed in early infancy, 

 and this in a manner practically impartial so far as in- 

 telligence is concerned. The rest are generally given 

 away, but what evidence have we that the less intelli- 

 gent of them are killed by their new masters, while the 

 more intelligent survive to perpetuate the race? 



Romanes has called attention^" to the inheritance of 

 an instinct in dogs which he considers especially invul- 

 nerable in support of the inheritance of acquired habit. 

 For an instinct to have been established solely by nat- 

 ural selection, it must be of sufficient importance to be 

 essential to the life of the race, so that those individ- 

 uals possessing it may alone survive. This is not the 



* The Factors of Organic Evolution. Nature. August 25, I887-XXXVI, 

 p. 40G. 



