Balanced Crosses 277 



compare the new form in this case with the type 

 from which it has originated, it may be seen 

 that the new character does not find its mate, 

 or its opposite, and it will be unpaired in the 

 hybrid. 



In the case of retrogressive changes the vis- 

 ible modification is due, at least in the best 

 known instances, to the reduction of an active 

 quality to a state of inactivity or latency. Now 

 if we make a cross between a species and its 

 variety, the differentiating character will be 

 due to the same internal unit, with no other 

 difference than that it is active in the species 

 and latent in the variety. In the hybrid these 

 two corresponding units will make a pair. But 

 while all other pairs in the same hybrid indi- 

 viduals consist of like antagonists, only this 

 pair consists of slightly unlike opponents. 



This conception of varietal crosses leads to 

 three assertions, which seem justifiable by 

 actual experience. 



First, there is no reason for a diminution of 

 the fertility, as all characters are paired in the 

 hybrid, and no disturbance whatever ensues in 

 its internal structure. Secondly, it is quite in- 

 different, how the two types are combined, or 

 which of them is chosen as pistillate and which 

 as staminate parent. The deviating pair will 

 have the same constitution in both cases, being 



