PLANT HYBRIDIZATION BEFORE MENDEL 317 



From all of which it appears that the actual composition of the 

 seeds of the four series was as follows, summarizing : 



It is now perfectly plain that the crossed plants in the four 

 series gave, in each serves,, all four of the theoretically possible 

 combinations for the series, and in equal numbers throughout. 



It is also plain that Series I and III, which are reciprocals, are 

 alike, and that Series II and IV, which are also reciprocals, are 

 also alike in the composition of their seeds. 



This would have seemed sufficient to prove the correctness of 

 Mendel's theory, that the pollen and egg cells of the hybrids 

 carry the dominant and the recessive characters in equal numbers, 

 and that consequently, in self -fertilized hybrids, all the possible 

 combinations of the unitary characters called "dominant''' and 

 "recessive" are to be found in the pollen and egg cells in equal 

 numbers. 



Mendel did not rest content, however, with the demonstration 

 which the experiment with the seed characters alone afforded. He 

 likewise experimented with the characters of flower-color and 

 length of stem, conducting the experiment so that, in the third 

 year of the investigation, each character ought to appear in half 

 of the plants, if the theory were correct. 



Using violet-red flower color as against white, and long stem as 

 against short, he had 166 plants to flower in the third year, dis- 

 tributed as follows : 



No. of plants 



47 

 40 



38 



41 



It is plain that the result is the same in kind as Mendel obtained 

 with the seed-characters. Even in addition to the experiments al- 

 ready carried out, Mendel further says : 



