88 CRITICISMS ON " THE ORIGIN OF SPECIES " m 



the parents. . . The external conditions of life, as climate and 

 food, &c., seem to have induced some slight modifications. 

 Habit, in producing constitutional differences, and use, in 

 strengthening, and disuse, in weakening and diminishing organs, 

 seem to have been more potent in their effects." 



And finally, as if to prevent all possible miscon- 

 ception, Mr. Darwin concludes his Chapter on 

 Variation with these pregnant words : 



' ' Whatever the cause may be of each slight difference in the 

 offspring from their parents and a cause for each must exist 

 it is the steady accumulation, through natural selection of such 

 differences, when beneficial to the individual, that gives rise to 

 all the more important modifications of structure, by whicli the 

 innumerable beings on the face of the earth are enabled to 

 struggle with each other, and the best adapted to survive." 



We have dwelt at length upon this subject, be- 

 cause of its great general importance, and because 

 we believe that Professor Kolliker's criticisms on 

 this head are based upon a misapprehension of Mr. 

 Darwin's views substantially they appear to us 

 to coincide with his own. The other objections 

 which Professor Kolliker enumerates and discusses 

 are the following : 1 



"1. No transitional forms between existing species are 

 known ; and known varieties, whether selected or spontaneous, 

 never go so far as to establish new species." 



To this Professor Kolliker appears to attach 

 some weight. He makes the suggestion that the 



1 Space will not allow us to give Professor Kolliker's argu- 

 ments in detail ; our readers will find a full and accurate version 

 of them in the Reader for August 13th and 20th, 1864. 



