102 BIOLOGY AND SOCIAL PROBLEMS 



duce changes in its habits, and changes in its 

 habits bring about changes in its structure. 

 Be these structural changes ever so shght, if 

 they recur regularly from generation to gen- 

 eration and are accumulated, they will even- 

 tually so modify an animal that a transmu- 

 tation of species may be said to occur. Thus 

 in an indirect way the ever changing environ- 

 ment is responsible for animal transformation. 



The Lamarckian hypothesis, thus stated, 

 appeals to the student of evolution through 

 its simplicity and directness. The ease with 

 which we may induce modifications in our own 

 bodies by voluntary change of habits is too 

 well known to require comment. The special 

 exercise of a set of muscles induces an increase 

 in their size and that of all their connected 

 parts, and the reverse of this is followed by 

 their shrinkage and decline. What could be 

 simpler than to conceive of a given animal 

 being what it is in consequence of its own ac- 

 tivities and those of its race ? Such an animal 

 may be assumed to possess its present form 

 in consequence of its racial habits. 



The application of this hypothesis to man 

 is most readily and easily accomplished, and 

 few organisms can be shown to afford a bet- 



