260 R. F. LICORISH [octobek 



both how separate parts as well as correlative parts are modified. 

 Present-day knowledge goes to show that such changes are brought 

 about through the co-operative influence of the correlative brain 

 centres. Yet, strange it is that the leader of the Neo-Lamarckians, 

 Mr. Herbert Spencer, while he cannot see how natural selection can 

 produce such changes as are shown in the neck, etc., of the elk, has to 

 fall back on natural selection to explain the modifications shown in 

 the fore-quarters of the giraffe, a more difficult matter than the elk's 

 neck to bring under the influence of natural selection. If the changes 

 in the elk's neck cannot be explained b) T natural selection, how can 

 the parts of the giraffe, a more marked form of correlative function 

 change, be so explained ? If natural selection is to be ruled out as 

 regards the elk's neck, it must more surely be ruled out as regards the 

 giraffe. 



I have already stated that Weismann, like a true Lamarckian, 

 attributes variations to the influences of the environment on the germ- 

 plasm during the ontogenetic development of the body. That being 

 granted, we can readily perceive how change of habit can produce in 

 time change of characters through inheritance of the functional modi- 

 fications brought about through the change of habit. It is well known 

 that many animals have, not one source of food supply, but several. 

 A bird that visits a flower for honey may also be insectivorous. One 

 source of food supply failing, the habit of constantly satisfying hunger 

 from another is taken on ; and this, by change in the method of feeding, 

 leads to the increase of use of certain characters which co-operatively 

 are brought into action, and the disuse of certain other characters. In 

 this way distribution of animals or change of conditions in situ leads 

 to new habits. But does the new habit modify the species in the 

 direction of better adaptation to the new mode of life ? I would 

 answer that if the experiences of the mother influence the foetus, and 

 act as external stimuli on the germinal cells, as is allowed by "Weis- 

 mann, we must see that changes in that experience, as brought about 

 by a new habit, must be reflected on the foetus, producing a variation 

 in the direction of better adaptation. And this process of better 

 adaptation in each successive offspring must, in time, render the 

 species fully adapted to its new mode of life. We find here not only 

 the cause of variation, but the gradual process by which species 

 through a change of habit becomes adapted to their new life. As the 

 functional changes affect characters, new species are produced. Now, 

 assuming that the Neo-Darwinians admit this modus operandi of the 

 formation of new habits, our explanation of the inheritance of func- 

 tional modifications of characters would harmonise the two schools, 

 i.e. if we allow that Weismann represents the Neo-Darwinians. 



Let us now consider how functional changes, as brought about 

 by a change of habit, modify anatomically the characters affected. 

 It must be plain that all modifications of form must have been 



