THEORY OF EVOLUTION 



The possibility of interchanging characters 

 might be illustrated over and over again. It is 

 true not only when two pairs of characters are 

 involved, but when three, four, or more enter 

 the cross. 



10 



10 



II 



01 



II 



01 



10 



10 



II 



01 



II 



01 



FIG. 25. Diagram to show the history of the factors in the 

 cross shown in Fig. 24. 



It is as though we took individuals apart 

 and put together parts of two, three or more 

 individuals by substituting one part for another. 



