26 MKNDELISM CHAP. 



3 showing the other dominant and the other recessive, 

 and i showing both recessive characters. And, as Men- 

 del pointed out, the principle may be extended in- 

 definitely. If, for example, the parents differ in three 

 pair of characters A, B, and C, respectively dominant to 

 a, b, and c, the Y 1 individuals will be all of the form 

 ABC, while the F 2 generation will consists of 27 ABC, 

 9 A Be; 9 AbC, 9 aBC, 3 Abe, 3 aBc, 3 abC, and_ i abc. 

 When individuals differing in a number of alternative 

 characters are crossed together, the hybrid generation, 

 provided that the original parents were of pure strains, 

 consists of plants of the same form ; but when these 

 are bred from a redistribution of the various characters 

 occurs. That redistribution follows the same definite 

 rule for each character, and if the constitution of the 

 original parents be known, the nature of the F 2 genera- 

 tion, i.e. the number of possible forms and the propor- 

 tions in which they occur, can be readily calculated. 

 Moreover, as Mendel showed, we can calculate also the 

 chances of any given form breeding true. To this point, 

 however, we shall return later. 



Of Mendel's experiments with beans it is sufficient to 

 say here that they corroborated his more ample work with 

 peas. He is also known to have made experiments with 

 many other plants, and a few of his results are incidentally 

 given in his series of letters to Nageli the botanist. To 

 the breeding and crossing of bees he also devoted much 



