APPENDIX 325 



Expt. 7. The offspring of 28 plants inherited the long axis, and 

 those of 72 plants some the long and some the short axis. 



In each of these experiments a certain number of the plants came 

 constant with the dominant character. For the determination of 

 the proportion in which the separation of the forms with the con- 

 stantly persistent character results, the two first experiments are 

 of especial importance, since in these a larger number of plants can 

 be compared. The ratios 1.93 to 1 and 2.13 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 smaller number of 

 100 trial plants. Experiment 5, which shows the greatest depar- 

 ture, was repeated, and then, in lieu of the ratio of 60 and 40, that 

 of 65 and 35 resulted. The average ratio of Q to I appears, therefore, 

 as fixed with certainty. It is therefore demonstrated that, of those 

 forms which possess the dominant character in the first generation, 

 two-thirds have the hybrid-character, while one-third remains 

 constant with the dominant character. 



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

 the dominant and recessive characters results in the first genera- 

 tion, 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 

 members of the first generation [F2] spring directly from the seed 

 of the hybrids [Fi], it is now clear that the hybrids form seeds having 

 one or other of the two differentiating characters, and of these one-half 

 develop again the hybrid form, while the other half yield plants which 

 remain constant and receive the dominant or the recessive characters 

 [respectively] in equal numbers. 



The Subsequent Generations [bred] from the Hybrids 



The proportions in which the descendants of the hybrids develop 

 and split up in the first and second generations presumably hold 

 good for all subsequent progeny. Experiments 1 and 2 have 

 already been carried through six generations, 3 and 7 through five, 

 and 4, 5, and 6 through four, these experiments being continued 

 from the third generation with a small number of plants, and no 

 departure from the rule has been perceptible. The offspring of the 

 hybrids separated in each generation in the ratio of 2:1:1 into 

 hybrids and constant forms. 



