I PROLOGUE 43 



descendants of the earlier. And the latter sup- 

 position is so vastly more probable than the former, 

 that rational men will adopt it, unless satisfactory 

 evidence to the contrary can be produced. The 

 objection sometimes put forward, that no one yet 

 professes to have seen one species pass into another, 

 comes oddly from those who believe that mankind 

 are all descended from Adam. Has any one then yet 

 seen the production of negroes from a white stock, 

 x or vice versd ? Moreover, is it absolutely necessary 

 to have watched every step of the progress of a 

 planet, to be justified in concluding that it really 

 does go round the sun ? If so, astronomy is in a 

 bad way. 



I do not, for a moment, presume to suggest that 

 some one, far better acquainted than I am with 

 astronomy and physics ; or that a master of the 

 new chemistry, with its extraordinary revelations ; 

 or that a student of the development of human 

 society, of language, and of religions, may not 

 find a sufficient foundation for the doctrine of 

 evolution in these several regions. On the contrary, 

 I rejoice to see that scientific investigation, in all 

 directions, is tending to the same result. And it 

 may well be, that it is only my long occupation 

 with biological matters that leads me to feel safer 

 among them than anywhere else. Be that as it 

 may, I take my stand on the facts of embryology 

 and of palaeontology ; and I hold that our present 

 knowledge of these facts is sufficiently thorough 



