THEORY OF EVOLUTION 57 



The possibility of interchanging characters 



might be ilhistrated over and over again. It is 



true not only when two pairs of characters are 



i involved, but when three, four, or more enter 



the cross. 



10 



10 



II 



01 



II 



10 



3i s 



I 



01 



00 ^ 





II 



01 



II 



I 



Fig. 25. Diagram to show the history of tlie factors in the 

 cross sliown in Fig. 2\. 



It is as though we took individuals apart 

 and put together parts of two, three or more 

 individual.*^ by substituting one part for another. 



