100 ORGANIC EVOLUTION — THE FACTORS 



this tlicory was not before Mr. Spencer I need not 

 discuss it further here, beyond saying that it offers an 

 explanation why " the mere cessation of selection should 

 cause decrease of an organ irresjpectivc of the direct effects 

 of disuse." 



Other parts of the passage quoted above call for 

 more detailed criticism. Mr. Spencer writes — "And 

 now, before leaving this question, let me remark on the 

 strange proposition which has to be defended by those 

 who deny the dwindling of organs by disuse. Their 

 proposition amounts to this — that for a hundred genera- 

 tions an inactive organ may be partially denuded of 

 blood all through life, and yet in the hundredth 

 generation will be produced of just the same size as in 

 the first." And this he writes but a few sentences after— 

 " Clearer conceptions of these matters would be reached 

 if, instead of thinking in abstract terms, the physio- 

 logical processes concerned were brought into the 

 foreground." 



Where shall we find a more daring misuse of 

 " abstract terms," or a more glaring disregard of " the 

 physiological processes concerned," than in the words 

 " for a hundred generations an inactive organ may be 

 partially denuded of blood all through life, and yet in 

 the hundredth generation will be produced of just the 

 same size as in the first " ? The words imply that the 

 same organ is " denuded of blood for a hundred 

 generations," whereas the truth is that a hundred 

 similctr organs in a hundred successive generations are 

 denuded of blood, wliich organs are only connected 

 with preceding and succeeding like organs through 

 germ cells, which are not in any way the products of 

 the organs, but are co-descendants with the cells of 

 the organs from a very remote cell-ancestry; at any 

 rate the germ cells have not been proved to be products 

 in part of the organs, and all theories as yet formulated 



