aug. 1899] THE SCOPE OF NATURAL SELECTION 115 



(a) Accommodations which are the direct result of environmental 



influence. 



(b) Accommodations which result from the activity of the organism 



itself in response to its environment. 



It is obvious that these two classes, though not usually so considered, 

 are in reality fundamentally distinct. Class (a) includes the only 

 kind of inherited characters that can be truly called acquired. 

 Class (b) includes what are in reality merely developments of already 

 existing somatic tendencies, which some biologists believe may, and 

 others that they may not, become germinal. In any case there must 

 be an elementary something which can be developed by use or there 

 would obviously be no development, but rather the formation of a 

 new character, and the accommodation would then have to be classed 

 under (a). In class (a) the influence of the environment in producing 

 a modification is one of primary cause and effect ; in class (b), on the 

 other hand, the influence of environment is secondary, it is the 

 indirect cause of the degree of the response, but not of the capacity of 

 responding which exists in the particular form of protoplasm itself. 

 Class (a) is incompatible with selection, for in proportion as direct 

 modification is able to occur, the less is the necessity of selection, and 

 this direct climatic influence must obviously be also inversely pro- 

 portional to the power of heredity. Class (b), on the other hand, is 

 not necessarily in opposition to the selection theory because within 

 certain limits the more responsive the organism the greater the rapidity 

 of development, selection would become simply more rigorous, the 

 selection value would be raised, the less responsive organisms being- 

 weeded out. 



There are thus two separate questions in this division to be 

 answered : — ■ 



1. Does a direct somatic alteration of structure ever occur as the 



result of climatic or other physical influence, and if so, how 

 frequently and under what conditions ? Do these altera- 

 tions become germinal ? or 



2. Do all, or any, somatic modifications to environment arise 



as developments of a pre-existing element in protoplasmic 

 structure ? If so, do somatic responses ever become ger- 

 minal ? For a clear statement of the Lamarckian position 

 it is necessary to determine the relation, if any exists, that 

 class («) has to class (&). 



3. By the selection of organisms which possess favourable varia- 

 tions, and by rejection of those which have unfavourable, the offspring 

 resulting will tend to reproduce the favourable variations of their 

 parents, and the selection being continued in every subsequent 

 generation, so long as conditions remain fairly constant, there must 



