16 PREFACE TO 



imagine, on strict inquiry, that the most careful breed- 

 ing will only fix and make prominent certain peculiar 

 features, or points, that are observed in certain families 

 of the same aboriginal species, or sub-species no more : 

 and that the whole world might be challenged to bring 

 evidence (such as would be admitted in an English court 

 of justice) that any permanent intermediate variety of 

 bird or animal, that would continue to reproduce off- 

 spring like itself, and not reverting to either original 

 type, have been originated by the crossing of any two 

 wild species. Yery numerous instances of the failure of 

 such experimental attempts might be adduced. The dif- 

 ficulty under which science labours in pursuing this in- 

 quiry, is much increased by the mystery in which almost 

 all breeders have involved their proceedings, even if they 

 have not purposely misled those who have endeavoured 

 to trace the means employed. 



As to the great question of the Immutability of Spe- 

 cies, so closely allied to the investigation of the different 

 varieties of poultry, as far as my own limited researches 

 have gone and they have been confined almost entirely 

 to birds under the influence of man they have led me 

 to the conclusion that even sub-species and varieties are 

 much more permanent, independent, and ancient, than 

 is currently believed at the present day. This result 

 has been to me unavoidable, as well as unexpected ; for, 

 as above mentioned, I started with a great idea of the 

 powerful transmuting influence of time, changed climate, 

 and increased food. My present conviction is, that the 

 diversities which we see in even the most nearly allied 

 species of birds, are not produced by any such influences, 

 nor by hybridisation ; but that each distinct species, 

 however nearly resembling any other, has been pro 



