Experimental Hybridizing 67 
heredity and evolution were being actively discussed during 
that time. It was not until 1900 that de Vries, and simul- 
taneously Correns and Tschermak, independently obtained re- 
sults that brought to light.again the long-forgotten discoveries 
of Mendel. 
Mendel found that when the flowers of one race of peas are 
fertilized artificially with pollen from anotHer race, the hybrid 
offspring (f,) of the first generation are like. one of the parents 
in each particular character, and not intermediate in character. 
If, however, these hybrids were self-fertilized or inbred, both 
grandparental types reappeared in their offspring (F,), and 
in definite proportions. The character of one of the parents 
that appears in the first hybrid generation (F,) is called the 
dominant, and the contrasted character of the other parent that 
disappears in the first hybrid generation is called the recessive. 
When these first hybrids are inbred as stated above, there ap- 
pears in the second generation of hybrids (F,) three individuals 
showing the dominant character to one individual showing the 
recessive. This, however, is by no means the whole discovery ; 
for Mendel found that the recessives of this second generation, 
if inbred, give always recessives and nothing else. Those that 
show the dominant character, on the other hand, do not all 
breed true. A third only are pure and give rise only to domi- 
nants, while two-thirds of them produce both dominants and 
recessives. The matter can be graphically expressed as fol- 
lows : — 
If we call the dominant character A, the recessive B, then the 
first generation (F,) of hybrids will be A(B). This means that 
while the hybrids show outwardly only the dominant character 
A, the recessive character (B) is also present in an undeveloped 
condition. When these hybrids (F,) are inbred, the A-char- 
acter dominates in one fourth of the offspring, the B-character 
in one fourth, and the A(B) character in two fourths, 7.e. in 
the proportion of 1: 2:1. Mendel showed by a simple 
1 In practice A(B) can only be distinguished from A by the kind of progeny 
that each produces. 
