358 OBJECTIONS TO THE THEORY [Chap. VIIl. 



such correlated modifications of structure could have 

 been slowly accumulated by natural selection. 



This difficulty, though appearing insuperable, is 

 lessened, or, as I believe, disappears, when it is remem- 

 bered that selection may be applied to the family, as 

 well as to the individual, and may thus gain the desired 

 end. Breeders of cattle wish the flesh and fat to be 

 well marbled together: an animal thus characterised 

 has been slaughtered, but the breeder has gone with 

 confidence to the same stock and has succeeded. Such 

 faith may be placed in the power of selection, that a 

 breed of cattle, always yielding oxen with extraordi- 

 narily long horns, could, it is probable, be formed by 

 carefully watching which individual bulls and cows, 

 when matched, produced oxen with the longest horns; 

 and yet no ox would ever have propagated its Mnd. 

 Here is a better and real illustration: according to M. 

 Verlot, some varieties of the double annual Stock from 

 having been long and carefully selected to the right 

 degree, always produce a large proportion of seedlings 

 bearing double and quite sterile flowers; but they like- 

 wise yield some single and fertile plants. These latter, 

 by which alone the variety can be propagated, may be 

 compared with the fertile male and female ants, and the 

 double sterile plants with the neuters of the same com- 

 munity. As with the varieties of the stock, so with so- 

 cial insects, selection has been applied to the family, and 

 not to the individual, for the sake of gaining a service- 

 able end. Hence we may conclude that slight modi- 

 fications of structure or of instinct, correlated with 

 the sterile condition of certain members of the com- 

 munity, have proved advantageous: consequently the 

 fertile males and females have flourished, and trans- 



