REPORT OF THE CONFERENCE ON GENETICS, 87 
These yellow seeds were sown the following year and the resulting 
plants were allowed to self-fertilise, and it was found that all the plantg 
in this generation bore seeds of both colours—egreen and yellow being often 
found in the same pod—proving that though in the first generation the 
ereen colour had receded from sight, it had still been present potentially 
in the offspring and came into sight again in the second generation; and 
not only came into sight again, but did so in an almost exact ratio, there 
being in this second generation a fairly constant proportion of one green 
seed to three yellow ones. 
Continuing with these seeds he found that next year in the third 
generation all the green ones of the second generation, when self-fertilised, 
produced only green ones in the third, and they again only green, and so 
Tic. 23.—GrecorR JoHANN MENDEL. 
From a vhotographic group taken about 1866, 
on until six generations had been proved with no trace of any reippearance 
of the dominant yellow ancestry: in other words, the Recessive character 
bred true. 
But it was not so with the yellow seeds of the second generation ; some 
of these when self-fertilised were found to produce both yellow and green 
seeds (often in the same pod) just as their parents had done in the first * 
* Owing to the fact that the cotyledons (or seed leaves) in peas are embryonic 
(i.e. the result of fertilisation), the seeds (except the outer skin or coat of each seed 
which is purely maternal) borne by the plant belong to a different generation from 
that of the plant itself; e.g. a pure parent plant crossed bears hybrid seeds of the 
first generation, these when sown produce the hybrid plants of the first generation, 
which in their turn bear seeds of the second generation, and so on, the seeds always 
exhibiting the effects of hybridisation a generation in front of the plants. (In 
‘ scientific terminology P, plants bear F, seeds; F, plants bear F’, seeds; F, plants bear 
F, seeds, and so on.) In view of this I have ignored the plant generations (which 
are not essential in this particular case) and referred only to the seed generations 
(which are all-important). 
