Balanced Crosses 



293 



Cross 



Mephisto ' 



1. Generation 2. Generation 3. Generation 



4- 100% Mephisto 



Danebrog 



/77.5% Dom.i 



■AH Mephisto/ 



22.5% Kecess. 



9- all hybrids with 

 83-68% domi- 

 nants and 17- 

 32% recessives. 



100% Dane- 

 brog. 



Examining these figures we find one-fourth of 

 constant recessives, as has already been said, 

 further one-fourth of constant dominants, and 

 the rest or one half as unstable hybrids. Both 

 of the pure groups have therefore reappeared 

 in the same numbers. Calling A the specimens 

 with the pure active mark, L those with the la- 

 tent mark, and H the hybrids, these proportions 

 may be expressed as follows : 



lA-f2H-f-lL. 



This simple law for the constitution of the sec- 

 ond generation of varietal hybrids with a single 

 differentiating mark in their parents is called 

 the law of Mendel. Mendel published it in 

 1865, but his paper remained nearly unknown 

 to scientific hybridists. It is only of late years 

 that it has assumed a high place in scientific 

 literature, and attained the first rank as an in- 

 vestigation on fundamental questions of hered- 



