66 Darwin, and after Darwin. 



So much for what Weismann has said touching this 

 matter. But the matter has also been dealt with both 

 by Darwin and by Wallace. Darwin very properly 

 distinguishes between the fallacy that " with animals 

 such as the giraffe, of which the whole structure is 

 admirably co-ordinated for certain purposes, it has 

 been supposed that all the parts must have been 

 simultaneously modified 1 ." and the sound argument 

 that the co-ordination itself cannot have been due to 

 natural selection alone. This important distinction 

 may be rendered more clear as follows. 



The facts of artificial selection prove that immense 

 modifications of structure may be caused by a cumu- 

 lative blending in the same individuals of characters 

 which were originally distributed among different 

 individuals. Now, in the parallel case of natural 

 selection the characters thus blended will usually 

 if not invariably be of an adaptive kind ; and their 

 eventual blending together in the same individuals 

 will be due to free intercrossing of the most fit 

 But this blending of adaptations is quite a different 

 matter from the occurrence of co-ordination. For 

 it belongs to the essence of co-ordination that each 

 of the co-ordinated parts should be destitute of adap- 

 tive value per se : the adaptation only begins to arise 

 if all the parts in question occur associated together in 

 the same individuals from the very first. In this 

 case it is obvious that the analogy of artificial selec- 

 tion can be of no avail in explaining the facts, 

 since the difficulty presented has nothing to do with 



Oct. 1893), and Th Effect of External Influences upon Development. 

 " Romanes Lecture " 1894, and Spencer, Weismannism once more (Cout 

 Rer. Oct. i8 94 \ C. LI. M.j 

 1 Variation, &c., vol. ii. p. 206. 



