EVOLUTION OF THE COLORS OF BIRDS. 41 



potent, that the additional hypothesis of use-inheritance 

 seems perfectly superfluous. Where intelligence is not 

 highly valued 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, 1887-XXXVI, 

 p. 406. 



