Darwin's Artificial and Natural Selection 165 



for my part, have never assumed this, and have on this very- 

 account enunciated the principle of panmixia. Now, although 

 this, as I have still no reason for doubting, is a perfectly cor- 

 rect principle, which really does have an essential and indis- 

 pensable share in the process of retrogression, still it is not 

 alone sufficient for a full explanation of the phenomena. 

 My opponents, in advancing this objection, were right, to the 

 extent indicated, and as I expressly acknowledge, although 

 they were unable to substitute anything positive in its stead 

 or to render my explanation complete. The very fact of the 

 cessation of control over the organ is sufficient to explain its 

 degeneration, that is, its deterioration, the disharmony of its 

 parts, but not the fact which actually and always occurs 

 where an organ has become useless — viz., its gradual and 

 unceasing diminution continuing for thousands ana thousands 

 of years and culminating in its final and absolute effacement." 



If then neither selection of persons nor the cessation of 

 personal selection can explain the phenomenon, we must 

 look elsewhere for the answer. This Weismann finds in 

 the application of Roux's hypothesis of the struggle_of the 

 parts to obtain nourishment. 



"JThe production of the long tail-feathers of the Japanese 

 cock does not repose solely on the displacement directly 

 effected by personal selection, of the zero point of variation 

 upward, but that it is also fostered and strengthened by 

 germinal selection. Were that not so, the phenomena of the 

 transmutation of species, in so far as fresh growth and the 

 enlargement and complication of organs already present are 

 concerned, would not be a whit more intelligible than they 

 were before." 



Thus Weismann has piled up one hypothesis on another as 

 though he could save the integrity of the theory of natural 

 selection by adding new speculative matter to it. The most 

 unfortunate feature is that the new speculation is skilfully 

 removed from the field of verification, and invisible germs 



