Those forms which in the first generation maintain the recessive
character do not further vary in the second generation as regards this
character; they remain constant in their offspring.
It is otherwise with those which possess the dominant character in
the first generation [bred from the hybrids]. Of these _two_-thirds
yield offspring which display the dominant and recessive characters
in the proportion of 3 to 1, and thereby show exactly the same ratio
as the hybrid forms, while only _one_-third remains with the dominant
character constant.