264 MISCELLANEOUS OBJECTIONS TO THE [Chap. TIL 



through the modification of their original types. The 

 many animals which have remained unchanged since 

 the commencement of the glacial period, would have 

 been an incomparably stronger case, for these have been 

 exposed to great changes of climate and have migrated 

 over great distances ; whereas, in Egypt, during the last 

 several thousand years, the conditions of life, as far as we 

 know, have remained absolutely uniform. The fact of little 

 or no modification having been effected since the glacial 

 period would have been of some avail against those who 

 believe in an innate and necessary law of development, 

 but is powerless against the doctrine of natural selec- 

 tion or the survival of the fittest, which implies that 

 when variations or individual differences of a beneficial 

 nature happen to arise, these will be preserved; but 

 this will be effected only under certain favourable 

 circumstances. 



The celebrated palaeontologist, Bronn, at the close of 

 his German translation of this work, asks, how, on the 

 principle of natural selection, can a variety live side by 

 side with the parent species ? If both have become 

 fitted for slightly different habits of life or conditions, 

 they might live together ; and if we lay on one side 

 polymorphic species, in which the variability seems to 

 be of a peculiar nature, and all mere temporary varia- 

 tions, such as size, albinism, &c, the more permanent 

 varieties are generally found, as far as I can discover, 

 inhabiting distinct stations, — such as high land or low 

 land, dry or moist districts. Moreover, in the case of 

 animals which wander much about and cross freely, 

 their varieties seem to be generally confined to distinct 

 regions. 



Bronn also insists that distinct species never differ 



