194 SELECTION. 



eral generations of selection according to this system must 

 lead to a rapid purification of the strain for the best geno- 

 type given in the potential variability of the original group. 

 This system of selection for egg-production in poultry is one 

 of very few instances, where it is possible for us geneticians to 

 point the way to the practical breeders. As we have pointed out 

 several times, the practicians as a rule have worked out empir- 

 ically a system of handling their material, which can hardly be 

 improved upon by the geneticists. 



