3 18 Habit and Instinct. 



modification start at a higher level, so to speak, and thus 

 enable it to be carried a step further. The latter will force 

 it to start at a lower level, and prevent its going so far. 

 If natural selection take place at all, we may well believe 

 that it would do so under such circumstances.* And it 

 would work along the lines laid down for it in adaptive 

 modification. Modification would lead ; variation follow 

 in its wake. It is not surprising that for long we believed 

 modification to be transmitted as hereditary variation. 

 Such an interpretation of the facts is the simpler and more 

 obvious. But simple and obvious interpretations are not 

 always correct. And if, on closer examination in the light 

 of fuller knowledge, they are found to present grave 

 difficulties, a less simple and less obvious interpretation 

 may claim our provisional acceptance. 



In his recent paper on Germinal Selection, Prof. 

 Weismann says : f "I am fain to relinquish myself to 

 the hope that now after another explanation has been 

 found, a reconciliation and unification of the hostile views 

 is not so very distant, and that then we can continue our 

 work together on the newly laid foundations." As one to 

 whom Prof. Weismann alludes as having expressed the 

 opinion that the Lamarekian principle must be admitted 

 as a working hypothesis, I am now ready to relinquish 

 myself also to the same hope. Germinal selection does 

 not convince me, though it may be regarded as a suggestive 

 hypothesis; and, assuredly, I am not convinced by the 

 argument that because in certain cases, such as the 

 changes in the chitinous parts of the skeleton of insects 

 and Crustacea, and in the teeth of mammals, use and 

 disuse can have played no part, therefore in no other 



* Prof. Weismann's "germinal selection," if a vera causa, would be a 

 co-operating factor, and assist in producing the requisite variations, 

 t Monist, loc. cit., p. 290. 



