1896. LYELL AND LAMARCKISM. 329. 



weaker, and the result is extermination ; but the inheritance of all 

 the effects of the conditions of life does not always lead to cumulative 

 destruction ; if it did, there would be nothing left alive, and the state- 

 ment that on Lamarckian principles it would, is equivalent to saying 

 that the conditions unfavourable to life are, on the whole, more 

 powerful than those which are favourable, a statement we know to be 

 untrue. What Lamarckians contend is, that the conditions of life 

 kill a large number of individuals and modify those which survive ; 

 that the struggle for existence not only involves the survival of the 

 fittest, but the formation of the fittest. Professor Brooks's argument 

 shows that he has quite failed to understand the Lamarckian view,. 

 and suggests strongly that he has never tried to do so. 



Professor Brooks maintains that the structural changes associated 

 with mental development are also, like the modification of muscles, 

 dependent on structural adjustments for bringing about this develop- 

 ment, and that the effects of the environment which are not "already 

 deducible from adaptive structure, must be haphazard." But we are 

 not told what are these other effects of the environment. The effects 

 which are stated by Brooks to be dependent on pre-existing capacities 

 are those which Lamarckians have chiefly in view. The others, it is 

 said, must be haphazard because they are not proved to be beneficial. 

 Now, to take an example, the excessive consumption of alcohol is not 

 beneficial, but are its effects therefore haphazard ? It does not follow 

 that, because the effect of a given condition is not beneficial, therefore 

 it must be indeterminate. On the contrary, science is founded on 

 the conclusion, drawn from experience, that the same conditions 

 always produce the same effects, and that is all that Lamarckians 

 contend for. 



We see, then, that Brooks's objection to Lamarckism, so far as 

 the effects of use and disuse are concerned, is that such effects are 

 due to structural arrangements already existing for the local increase 

 or decrease in the supply of the nutritive fluids, or blood, and that 

 Lamarckism does not explain these structural arrangements. We 

 have seen that, if this objection were valid,'Lamarckian effects would 

 explain all the modifications in animals which have taken place since 

 they had a circulation. But we have seen also that the objection is 

 fallacious, because the supply of nourishment does not necessarily 

 imply assimilation and growth, which are the results of stimulation. 

 The effects of a profusion of nourishment and absence of stimulation 

 are sufficiently notorious in the phenomena of parasitism. Is 

 Professor Brooks unaware that Lamarckism extends to plants, and 

 if not, can he suggest that the modification of flowers by the irritation 

 due to insects depends on structural arrangements for the supply of 

 nutrient fluids? 



Professor Brooks has misinterpreted in the most astonishing, 

 manner one statement of Romanes, that " no question of value, as 

 selective or otherwise, can obtain " in the case of Lamarckian factors. 



