in MENDEL'S WORK 19 



dwarfness the recessive character. The next stage was to 

 collect and sow the seeds of these tall hybrids. Such 

 seeds in the following year gave rise to a mixed genera- 

 tion consisting of tails and dwarfs but no intermediates. 

 By raising a considerable number of such plants Mendel 

 was able to establish the fact that the number of tails 

 which occurred in this generation was almost exactly 

 three times as great as the number of the dwarfs. As in 

 the previous year, seed were carefully collected from this, 

 the second hybrid generation, and in every case the seeds 

 from each individual plant were harvested separately and 

 separately sown in the following year. By this respect for 

 the individuality of the different plants, however closely 

 they resembled one another, Mendel found the clue that 

 had eluded the efforts of all his predecessors. The seeds 

 collected from the dwarf recessives bred true, giving noth- 

 ing but dwarfs. And this was true for every dwarf tested. 

 But with the tails it was quite otherwise. Although in- 

 distinguishable in ^ 

 appearance, some 



of them bred true, T(D) F, 



while others be- | I , 



haved like the T T ( D ) T ( D ) D — F * 



original tall hy- r— 



brids, giving a T TT(D) T(D) D TT(D) T(D) D »-~ F * 

 generation con- T D — F 4 



sisting of tails and dwarfs in the proportion of three of 



