//. IV. Conn 367 



perhaps after hundreds of generations, there does appear a con- 

 genital variation which aids the animal in its new habit, an 



old habit by this time, — such variations will be selected and 

 become a part of the inheritance of the race. The individuals 

 with these congenital variations will, from the outset, have an 

 advantage over others, since the congenital variations will 

 enable them to adapt themselves more closely to the conditions 

 than would purely acquired characters. Thus the acquired 

 characters keep the individual alive until the proper congenital 

 variations appear, and the new habit actually determines what 

 sort of congenital variations shall be preserved, and guides the 

 process of evolution. 



'' Perhaps a concrete case may make this somewhat obscure 

 theory a little clearer. Imagine, for example, that some change 

 in conditions forced an early monkey-like animal, that lived on 

 the ground, to escape from its enemies by climbing trees. 

 This arboreal habit was so useful to him that he continued it 

 during his life, and his offspring, being from birth kept in the 

 trees, acquired the same habit. Now it would be sure to follow 

 that the new method of using their muscles w^ould soon adapt 

 them more closely to the duty of climbing. Changes in the 

 development of different parts of the body would inevitably 

 occur as the direct result of the new environment, and they 

 would all be acquired characters. The children would develop 

 the same muscles, tendons, and bones, since they too lived in 

 the trees and had the same influences acting upon them. Such 

 acquired characters would enable the animals to live in the trees, 

 and would thus determine which individuals should survive in 

 the struggle for existence, for these modified individuals would 

 clearly have the advantage over those that stayed on the ground, 

 or did not become properly adapted to arboreal life by acquired 

 habits. All this would take place without any necessity for 

 a congenital variation or the inheritance of any character which 

 especially adapted the monkey for life in the trees. 



" But, in the monkeys thus preserved, congenital variations 

 would be ever appearing in all directions. It v.ould be sure to 

 follow that after a time there might be some congenital variation 



