182 ILLINOIS STATE ACADEMY OF SCIENCE 



1. "Does selection use germinal differences already 

 present or such as arise during experiment, or both?" 

 He thinks that, assuming the factors are Mendelian, se- 

 lection in a group heterozygous for many minor factors 

 will be effective in isolating favorable combinations of 

 such modifying genes or multiple factors. Since muta- 

 tions take place at all times, selection may make use of 

 variations arising during the experiment. 



2. "In case it uses new differences does it cause them 

 to occur more frequently and does it influence their direc- 

 tions?" He finds nothing to show that favorable varia- 

 tions occur oftener on account of selection. 



3. "Are differences new or otherwise more likely to 

 occur in the locus of the gene under observation or in 

 other loci?" He thinks variations appear more often in 

 other factors since there are so many, but only in one 

 that is responsible for the difference under observation. 



TABLE OF MEANS AND DIFFERENCES WITH P. E. 



