l66 THE FOUNDATIONS OF ZOOLOGY 



to lose ground for many generations, during which there are 

 innumerable opportunities for every useful quality to count for 

 all it is worth. The survivors are the ones in which all these 

 useful qualities are most perfectly coordinated, and the effect of 

 the struggle is to make this coordination more and more perfect, 

 although we must remember that no essential change can occur 

 in a type unless some change in the external world makes a 

 place for a new type. 



"That natural selection generally acts with extreme slowness," 

 says Darwin, "I fully admit. It can act only when there are 

 places in the natural polity of a district which can be better 

 occupied by the modification of some of its existing inhabitants. 

 The occurrence of such places will often depend on physical 

 changes, which generally take place very slowly, and on the im- 

 migration of better adapted forms being prevented. As some few 

 of the old inhabitants become modified, the mutual relations of 

 others will often be disturbed ; and this will create new places, 

 ready to be filled up by better adapted forms; but all this will 

 take place very slowly. Although all the individuals of the same 

 species differ in some slight degree from each other, it would often 

 be long before differences of the right nature in various parts of 

 the organization might occur." ^ 



The passage I have quoted from Galton seems to indicate that, 

 after all, he may believe that the specific types of zoology and 

 botany are nothing more than the persistent effects of past selec- 

 tion, and that his statement that "organic stability is independent 

 of selection" may refer to present selection only. 



These statements are clear and explicit, however, and they have 

 been interpreted by most readers as a flat contradiction of the 

 view that the mechanism which leads to the formation of new 

 types is identical, on its vital side, with that which preserves es- 

 tablished types ; the view that the differences between the two 

 are differences in the external world. 



He says {^Nature, September, 1885): "It is some years since I 

 made an extensive series of experiments in the produce of seeds 

 of different sizes, but of the same species. ... It appears from 

 these experiments that the offspring did not tend to resemble their 



1 " Origin of Species," p. 84. 



