664 APPENDIX B. 



incut falls to ,he ground. Nay, it falls to the ground even if con- 

 clusions so definite as these be not insisted upon ; for before he 

 can get a basis for his argument he must give good reasons for 

 concluding that these traits of the Amazon-ants have not been 

 inherited from remote ancestors. 



One more step remains. Let us grant him his basis, and lot 

 us pass from the above negative criticism to a positive criticism. 

 As before, I decline to follow the practice of talking in abstracts 

 instead of in concretes, and contend that, difficult as it may be to 

 see how natural selection has in all cases operated, we ought, at 

 any rate, to trace out its operation whenever we can, and see. 

 where the hypothesis lands us. According to Professor Weis- 

 mann's admission, for production of the Amazon-ant by natural 

 selection, "many parts must have varied simultaneously and in 

 harmony with one another ; " * and he names as such, larger 

 jaws, muscles to move them, larger head, and thicker chitin for 

 it, bigger nerves for the muscles, bigger motor centres in the 

 brain, and, for the support of the big head, strengthening of the 

 thorax, limbs, and skeleton generally. As he admits, all these 

 parts must have varied simultaneously in due proportion to one 

 another. What must have been the proximate causes of their 

 variations ? They must have been variations in what he calls the 

 " determinants." He says : 



"We have, however, to deal with the transmission of parts which are 

 variable and this necessitates the assumption that just as many independent 

 and variable parts exist in the germ-plasm as are present in the" fully formed 

 organism." f 



Consequently to produce simultaneously these many variations 

 of parts, adjusted in their sizes and shapes, there must have 

 simultaneously arisen a set of corresponding variations in the 

 " determinants " composing the germ-plasm. What made them 

 simultaneously vary in the requisite ways ? Professor Weismann 

 will not say that there was somewhere a foregone intention. 

 This would imply supernatural agency. He makes no attempt 

 to assign a physical cause for these simultaneous appropriate 

 variations in the determinants : an adequate physical cause being 

 inconceivable. W T hat, then, remains as the only possible inter- 

 pretation ? Nothing but a fortuitous concourse of variations j re- 

 minding us of the old " fortuitous concourse of atoms." Nay, 

 indeed, it is the very same thing. For each of the " determinants," 

 made up of "biophors," and these again of protein-molecules, and 

 these again of simpler chemical molecules, must have had its 

 molecular constitution changed in the required way ; and the 

 molecular constitutions of all the " determinants," severally modi- 

 fied differently, but in adjustment to one another, must have been 

 * Loc. cit., p. 318. f The Germ Plasm, p. 54. 



