MENDEL 



17 



In the second and fourth experi- 

 ments the round and yellow seeds 

 yielded plants with round and wrin- 

 kled yellow and green seeds, AaBb. 



From the round green seeds, plants 

 resulted with round and wrinkled 

 green seeds, Aab. 



The wrinkled yellow seeds gave 

 plants with wrinkled yellow and green 

 seeds, aBb. 



From the wrinkled green seeds 

 plants were raised which yielded again 

 only wrinkled and green seeds, ab. 



Although in these two experiments 

 likewise some seeds did not germinate, 

 the figures arrived at already in the 

 previous year were not affected 

 thereby, since each kind of seed gave 

 plants which, as regards their seed, 

 were like each other and different from 

 the others. There resulted therefore 

 from the 



2d Exp. 4th Exp. 



31 24 plants of the form AaBb 



26 25 " " " " Aab 



27 22 " " " " aBb 

 26 27 " " " " ab 



In all the experiments, therefore, 

 there appeared all the forms which the 

 proposed theory demands, and they 

 came in nearly equal numbers. 



In a further experiment the char- 

 acters of flower-colour and length of 

 stem were experimented upon, and se- 

 lection was so made that in the third 

 year of the experiment each character 

 ought to appear in half of all the plants 

 if the above theory were correct. A, 

 B, a, b serve again as indicating the 

 various characters. 



A, violet-red flowers 



B, axis long. 



a, white flowers 



b, axis short. 



ab, whence the hybrid aBb. In the sec- 

 ond year, for further fertilisation, the 

 hybrid Aab was used as seed parent, 

 and hybrid aBb as pollen parent. 



Seed parent, Aab. 

 Possible egg cells, Ab, ab. 

 Pollen parent, aBb. 

 Pollen cells, aB, ab. 



From the fertilisation between the 

 possible egg and pollen cells four com- 

 binations should result, viz., 



AaBb + aBb + Aab + ab. 



From this it is perceived that, ac- 

 cording to the above theory, in the 

 third year of the experiment out of all 

 the plants 



Half should have violet-red flowers 

 (Aa), Classes 1, 3. 



Half should have white flowers (a). 

 Classes 2, 4. 



Half should have a long axis (Bb), 

 Classes 1, 2. 



Half should have a short axis (b), 

 Classes 3, 4. 



From 45 fertilisations of the second 

 year 187 seeds resulted, of which only 

 166 reached the flowering stage in the 

 third year. Among these the separate 

 classes appeared in the numbers fol- 

 lowing: 



Class 

 1 

 2 

 3 

 4 



Color 

 of flower 

 violet-red 

 white 

 violet-red 

 white 



Stem 



long 



long 



short 



short 



47 times 



40 " 

 38 " 



41 " 



The form Ab was fertilised with ab, 

 which produced the hybrid Aab. Fur- 

 thermore, aB was also fertilised with 



There subsequently appeared 



The violet-red flower-colour (Aa) 

 in 85 plants. 



The white flower-colour (a) in 81 

 plants. 



