LAMAECK ON ADAPTATION. II5 



have arisen from the habit of fetching their food out of 

 narrow, small, and deep crevices or channels. The webs 

 between the toes of the webbed feet in frogs and other 

 aquatic animals have arisen solely from the constant endea- 

 vour to swim, from striking their feet against the water, 

 and from the very movements of swimming. Inheritance 

 fixed these habits on the descendants, and finally, by further 

 elaboration, the organs were entirely transformed. However 

 correct, as a whole, this fundamental thought may be, yet 

 Lamarck lays the ^Lress too exclusively on habit (use and 

 non-use of organs), certainly one of the most important, but 

 not the only cause of the change of forms. Still this cannot 

 prevent our acknowledging that Lamarck quite correctly 

 appreciated the mutual co-operation of the two organic 

 formative tendencies of Adaptation and Inheritance. What 

 he failed to grasp is the exceedingly important principle of 

 " Natural Selection in the Struggle for Existence," with 

 which Darwin, fifty years later, made us acquainted. 



It still remains to be mentioned as a special merit of 

 Lamarck, that he endeavoured to prove the development of 

 the human race from other primitive, ape-like mammals 

 Here again it was, above all, to habit that he ascribed the 

 transforming, the eimobling influence. He assumed that the 

 lowest, original men had originated out of men-like apes, by 

 the latter accustoming themselves to walk upright. The 

 raising of the body, the constant efibrt to keep upright, in 

 the first place led to a transformation of the limbs, to a 

 stronger difierentiation or separation of the fore and hinder 

 extremities, which is justly considered one of the most 

 essential distinctions between man and the ape. Behind, 

 the calf of the leg and the flat soles of the feet were 



