m MENDEL'S WORK 17 



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 genaration 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 nothing but dwarfs. And 

 this was true for every dwarf tested. But with the 

 tails it was quite otherwise. Although indistinguish- 

 able in appearance, some of them bred true, while 

 others behaved like the original tall hybrids, giving a 

 generation con- 



sisting of tails 

 and dwarfs in 

 the proportion of 

 three of the for- 

 mer to one of the 



T X D 



I 

 T(D)-- 



T{D) T(D) D — F2 



latter. Counting | 1 1 — \ 1 1 — r — r — 1 | 



showed that the T Tt(D) t(D) DTt(D) t(D)D D-F3 



number of the ^ j!j p 



tails which gave 



dwarfs was double that of the tails which bred true. 



C 



