DARWINISM ATTACKED. 51 



only be reached by a leap, while the selection theory pre- 

 supposes slight gradual stages of complication. 



Wolff 26 expresses another phase of this objection by re- 



ferring to a few of many cases of complex relations between 



entirely distinct organs in the body, which 



Difficulty of J J ' 



explaining com- relations constitute some of the most important 



functions of the body. For the successful 

 parts by selec- establishment of these relations it has been 

 necessary, as Wolff expresses it, "that for each 

 advance in development or complexity of one definite pecu- 

 liarity in an organ there must appear corresponding and 

 exact definite advance in development or complexity of a 

 peculiarity in another entirely distinct organ." Wolff's first 

 example is the relationship existing between the muscles 

 and nerves of the higher animals. The intimate, delicate, 

 and precise character of the relations between the nerve-end- 

 ings and the muscle cells, to be explicable by selection of 

 fortuitous variations, must have required coincident varia- 

 tions both in structure and functions of each muscle cell and 

 each nerve-ending that are impossible to conceive of. "It 

 might be," says Wolff, "possible to picture the gradual 

 development of the relations between one muscle cell and 

 one nerve-ending on the basis of a selection among infinitely 

 fortuitous variations, but that such variation shall occur 

 coincidently in time and character in hundreds or thousands 

 of cases in one organism is inconceivable." 



In the case of organs whose functions are regulated from 

 a common centre, the development of centre and of organs 

 must have gone on coincidently and could not have been 

 independent. The development of the eye is useless if 

 the development of the optic centre did not go hand in 

 hand with it. Without the one the other has no reason, 

 no significance, therefore selection could have brought 

 neither to its proper development independently. The 

 coincident appearance, however, of organ and centre can 



