264 MISCELLANEOUS OBJECTIONS TO THE [Chap. VII. 



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 de- 

 velopment, but is powerless against the doctrine of natu- 

 ral selection or the Survival of the fittest, which implies 

 that when variations or individual differences of a bene- 

 ficial 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 poly- 

 morphic species, in which the variability seems to be 

 of a peculiar nature, and all mere temporary variations, 

 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 ease 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 



