290 THE COLOURS OF ANIMALS 



wild and twenty domestic ducks showed that the brain 

 of the former is, in proportion to the weight of the 

 body, nearly twice as heavy as that of the latter. 

 The average weights were as follows : 



Domestic duck . . 1816-768 grammes 

 Brain of . . 5-370 



Wild duck . . . 1155-813 

 Brain of ... 6-433 

 Brain weight to body weight as 1 to 338-318 in domestic duck 

 1 to 179-669 in wild duck. 



These results were confirmed by the examination of 

 over sixty individuals, in addition to the forty alluded 

 to above. 



The effects of this degeneration are seen in the 

 fact that the ' wild duck is, from first to last, a superior 

 being, mentally considered, and exhibits an amount of 

 intellectual and instinctive acuteness, and force and 

 independence of character, to which the barn-door 

 variety can make no pretension.' A careful com- 

 parison of the habits and instincts of the type with 

 those of the domestic race, shows that ' altogether 

 there is a mental sprightliness and momentum in the 

 wild duck that have no counterparts in its domestic 

 congener.' The domestic duck, ever since its first 

 subjugation by man, ' for eighteen centuries, and not- 

 withstanding occasional infusions of wild blood, has 

 been sinking into imbecility.' 



These facts are also true of many other domesti- 

 cated animals, and they serve to indicate that Sexual 

 Selection can only be tested fairly by the observation 



