Heredity 165 



determination of the proportion in which the separation 

 of the forms with the constantly persistent character 

 results, the first two experiments are of especial importance 

 since in these a greater number of plants can be compared. 

 The ratios 1.93 to 1 and 2.3 to 1 gave together almost 

 exactly the average ratio of 2 to 1. The sixth experiment 

 gave a quite concordant result; in the others the ratio 

 varies more or less, as was only to be expected in view of 

 the small number of 100 trial plants. Experiment 5, 

 which shows the greatest departure, was repeated, and 

 then in place of the ratio of 60 and 40 that of 65 and 35 

 resulted. The average ratio of 2 to 1 appears, therefore, 

 as fixed with certainty. It is, therefore, demonstrated 

 that, of those forms which possess the dominant character 

 in the second generation, two-thirds have the hybrid- 

 characters, while one-third remain constant with the 

 dominant characters. 



The ratio of 3 to 1, in accordance with which the dis- 

 tribution of the dominant and recessive characters re- 

 sults in the second generation, resolves itself, therefore, in 

 all experiments into the ratio of 2 : 1 : 1 if the dominant 

 character be differentiated according to its significance 

 as a hybrid-character or as a parental one. Since the 

 second generation (^ 2 ) springs directly from the seed of 

 the first generation (Fi), it is now clear that the hybrids 

 from seeds have one or the other of the two differen- 

 tiating characters, and of those one-half develop again 

 the hybrid form, while the other yields plants which re- 

 main constant and receive the dominant or the recessive 

 characters, respectively, in equal numbers. 



Dominance and recessiveness. Which characters will 



