OBJECTIONS TO THE THEORY 291 



been an ordinary animal, I should have unhesitatingly as- 

 sumed that all its characters had been slowly acquired through 

 natural selection ; namely, by individuals having been born 

 with slight profitable modifications, which were inherited by 

 the offspring; and that these again varied and again were 

 selected, and so onwards. But with the working ant we have 

 an insect differing greatly from its parents, yet absc^utely 

 sterile, so that it could never have transmitted successively 

 acquired modifications of structure or instinct to its progeny. 

 It may well be asked how is it possible to reconcile this case 

 with the theory of natural selection? 



First, let it be remembered that we have innumerable in- 

 stances, both in our domestic productions and in those in a 

 state of nature, of all sorts of differences of inherited struc- 

 ture which are correlated with certain ages, and with either 

 sex. We have differences correlated not only with one sex, 

 but with that short period when the reproductive system is 

 active, as in the nuptial plumage of many birds, and in the 

 hooked jaws of the male salmon. We have even slight dif- 

 ferences in the horns of different breeds of cattle in relation 

 to an artificially imperfect state of the male sex; for oxen 

 of certain breeds have longer horns than the oxen of other 

 breeds, relatively to the length of the horns in both the bulls 

 and cows of these same breeds. Hence I can see no great 

 difficulty in any character becoming correlated with the sterile 

 condition of certain members of insect-communities: the dif- 

 ficulty lies in understanding how 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 remembered that selec- 

 tion 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 extraordinarily long 

 horns, could, it is probable, be formed by carefully watching 

 which individual bulls and cows, when matched, produce oxen 



