48 BREEDING 



The nature and result of the union between two 

 persons, both with duplex eyes, may be any one of 

 the three following kinds : — 



A. Pure duplex by pure duplex, giving all pure 



duplex. 



B. Pure duplex by hybrid duplex, giving these 



two kinds in equal numbers. 

 c. Hybrid duplex by hybrid duplex, giving 25 per 

 cent, pure duplex, 50 per cent, hybrid duplex, 

 and 25 per cent, simplex. 



Unions between duplex and simplex can only be 

 of two kinds : — 



D. Pure duplex by simplex, giving all hybrid 



duplex. 



E. Hybrid duplex by simplex, giving hybrid 



duplexes, and simplexes, in equal numbers. 



Unions between two simplexes can only be of one 

 kind, inasmuch as there is only one kind of simplex, 

 the pure. 



The above statements are true of the three kinds, 

 simplex, pure duplex, and hybrid duplex, whatever 

 may have been their origin. Thus, if a simplex 

 occurring in the second hybrid generation mates 

 with another simplex of like extraction he or she 

 will produce nothing but simplexes as assuredly as 

 will two individuals both with simplex eyes who 

 have descended from, say, two generations of simplex 

 ancestry. Or, to express this in general terms, the 

 offspring of a man and a woman both possessing blue 



