The Problem Stated 21 



the present purpose. If nature's laws are 

 uniform in operation, such variations in the 

 action of energy must necessarily produce 

 variations in individuals. Also, if nature's 

 laws are uniform, such variations in indi- 

 viduals necessarily imply the action of energy 

 to produce them. A measurement of the 

 amount of change in individuals from one 

 generation to the next, divided by the change 

 in the application of energy, should furnish 

 a numerical value for the resistance of hered- 

 ity. A sorting process in reproduction by 

 which some things are included and others 

 omitted is not a change, and does not involve 

 the expenditure of energy except inasmuch 

 as the sorting action involves it. Likewise, 

 the suppression of a secondary sexual charac- 

 ter in that sex in which it normally does not 

 appear, represents a difference in form of 

 energy, or the temporary closing of a channel 

 through which energy flows, and not a change 

 in the amount of energy. 



Occasionally we find an animal which, at 

 some particular age, possesses a greater quan- 



