142 Heredity and Social Progress 



ment in survival and adjustment. Radical 

 alterations in the environment must therefore 

 make marked changes in those outer organs 

 which affect immediate adjustment. If an 

 organism changes from a life in the water to 

 one on the land, devolution must cut off or 

 powerfully alter the older organs and new 

 organs must develop to supplement them 

 where they are incapable of modification to 

 meet the new conditions. By the force of 

 these conditions the older organs in the outer 

 bodies of men have practically disappeared. 

 Men do not have the gills of fish or the 

 tails of reptiles. 



If there is an inner body of parallel growth 

 on which emotion and devolution have less 

 effect, these primitive organs would remain 

 and be capable of activity in men. We 

 would, in other words, have fish thoughts, 

 reptile thoughts, and monkey thoughts, even 

 though the outer organs through which these 

 inner organs once found expression no longer 

 exist. Is there any way of testing this sup- 

 position or of observing the activity of inner 

 organs which have no outer organs of expres- 



