86 Heredity and Social Progress 



These two conditions involve all the others. 

 Sensation is the final result of the first stage 

 of development, and the beginning of a new 

 epoch in which external conditions have a domi- 

 nant place. It is thus the beginning or the end, 

 just as the emphasis is placed on life or on 

 survival. 



If this be so, the two parts of my argu- 

 ment agree. The problem is, How is the sur- 

 plus energy of improved economic conditions 

 utilized to make permanent changes in organ- 

 isms and to allow the effects of economic 

 betterments to perpetuate themselves ? The 

 reply in terms of biology is that increased 

 nutrition results in a larger number of so- 

 matic cells, the unequal growth of which 

 causes folds which are centres of reproduction. 

 The germs created in these incipient ovaries 

 are cast off if the rapidity of growth does 

 not cause them to be enclosed and retained as 

 parts of the organism. They are then trans- 

 formed into nerves which are better channels 

 for nervous currents than are somatic cells. 

 So long as growth is dominant, the number of 

 folds increases, bringing with them a more 



