396 ADAPTIVE VAEIATIONS. 



small hind legs, represented (Weismann supposes) by 

 weaker determinants in the germ, are as favourably 

 placed in the struggle for existence as those with large 

 hind legs, represented by stronger germ determinants. 

 The weaker determinants, in their struggle with the 

 other determinants which represent useful organs in the 

 body, will be worsted, and gradually become more and 

 more enfeebled, the hind legs which they represent be- 

 coming correspondingly smaller and smaller till they 

 finally disappear altogether. Supposing, on the other 

 hand, that the individuals showing a greater develop- 

 ment of any particular characters than the average are 

 for this reason favoured by Selection, then the determi- 

 nants representing these characters in the germ-plasm 

 will also be more powerful than the average, and by ab- 

 sorbing more nutriment will become still more robust, 

 and produce descendants exhibiting the characters in 

 an increased degree. That is to say, the descendants 

 will, by Germinal Selection, become more and more 

 adapted to the conditions in respect of which they were 

 originally favoured by Natural Selection. 



This theory, though plausible enough, is absolutely 

 opposed to fact in so far as it relates to the evolution of 

 more adaptive forms. As we have seen in Chapter 

 IV., so far from the individuals selected in respect of 

 any character tending to transmit that character in in- 

 creased strength to their descendants, they almost in- 

 variably transmit less of it, or the offspring show, on an 

 average, a greater or less degree of regression towards 

 mediocrity, according to the amount of the character 

 present in their more remote ancestors. 



The degeneration of disused organs is, it must be ad- 



