THE PHENOMENA OF ORGANIC NATURE. 145 



thesis or supposition tliau one of successive modifica- 

 tion ? But if the population of the worlds in any age^ 

 is the result of the gradual modification of the forms 

 which peopled it in the preceding age, — if that has heen 

 the case, it is intelligible enough ; because we may 

 expect that the creature that results from the modifi- 

 cation of an elephantine mammal shall be something 

 like an elephant, and the creature which is produced by 

 the modification of an armadillo-like mammal shall be 

 like an armadillo. Upon that supposition, I say, the 

 facts are intelligible; upon any other, that I am aware 

 of, thev are not. 



So far, the facts of palaeontology are consistent with 

 almost any form of the doctrine of progressive modifi- 

 cation ; they would not be absolutely inconsistent with 

 the wild speculations of De Maillet, or with the less 

 objectionable hypothesis of Lamarck. But Mr. Dar- 

 win^s views have one peculiar merit ; and that is, that 

 they are perfectly consistent with an array of facts which 

 are utterly inconsistent with and fatal to, any other 

 hypothesis of progressive modification which has yet 

 been advanced. It is one remarkable peculiarity of 

 Mr. Darwin^s hypothesis that it involves no necessary 

 progression or incessant modification, and that it is 

 perfectly consistent with the persistence for any length 

 of time of a given primitive stock, contemporaneously 

 with its modifications. To return to the case of the 

 domestic breeds of pigeons, for example ; you have the 

 Dove-cot pigeon, which closely resembles the Rock 

 pigeon, from which they all started, existing at the 

 same time with the others. And if species are de- 

 veloped in the same way in nature, a primitive stock 



