CONCLUDING CONSIDERATIONS. 339 



they ever in any experience in any experience that is 

 recorded even accumulate into something that, compared 

 with their primitive, is essentially different, essentially 

 new ? The tame duck varies from the wild, the hackney 

 from the charger, the new foraminifer from the old, 

 but, as we have seen more than once already, ducks are 

 still ducks, horses are still horses, foraminifera are still 

 foraminifera ; and, in the same way, those wonderful 

 parrots that in four hundred years have changed as much 

 as they are said to have changed (I have only heard I 

 have not myself read) are still parrots. Why, are not 

 the blackbirds in Arcadian Cyllene (Aristotle) ay and 

 elsewhere (Cuvier) white ? Or, after two thousand 

 five hundred years, do not we see cocks, pheasants, and 

 peacocks very much the same as those Solon and 

 Cro3sus saw ? 



