9 8 THEORIES OF EVOLUTION 



exception of France/is the theorywe usually attribute 

 to Lamarck. Erasmus Darwin in England, however, 

 has the priority, in that he first brought forward the 

 principles which Lamarck more effectively supported. 

 But to Herbert Spencer belongs the chief credit, because 

 he has taken that part of the earlier theory which is 

 acceptable to modern biological thought, and upon this 

 basis has formed his great theory of evolution. 



Lamarck believed in an innate tendency toward 

 perfection in animals. Now, that is a view which very 

 few zoologists at the present time, if any, would dare 

 to sustain. In fact, an evolution due to an innate 

 principle of perfection is not very far removed from 

 special creation, — a doctrine which opposes any theory 

 of evolution. Herbert Spencer, therefore, rejecting all 

 those elements of Lamarck, which the scientific world 

 could not possibly accept, has taken that which was 

 likely to commend itself to science, and upon it has formed 

 his great theory of evolution ; so that the Lamarckian 

 Theory, as presented to the world to-day, comes before 

 it in Spencerian language, and in the closest relation 

 to Spencerian thought. In saying this, however, I do 

 not by any means intend to be understood as supporting 

 Spencer's theories or the views upon which he bases them. 



The Lamarckian Theory, then, upon which Spencer 

 has based his philosophy, is a theory of evolution de- 

 pendent, not like Natural Selection upon three factors, 

 but upon two. It depends first of all upon the effect 

 wrought on the individual by that which happens during 

 its lifetime. Instead of depending on those innate and 

 essential differences upon which Natural Selection rests, 

 this theory depends on those changes which are caused 

 during the life of the individual, — the action of some 

 external force upon it, the effect of its own will, the 

 changes produced by the use and disuse of its own parts. 

 The Lamarckian Theory depends in fact on all those 

 changes in an individual which we now call its Acquired 

 Characters ; that is, characters which the individual has 

 come to possess but which were not potentially present 

 at the very beginning of its development. 



