224 MENDELISM 
instance, when the non-development of pigment leads 
to the appearance of white flowers. 
We can now realize how necessary it is, in order to 
avoid hopeless confusion, to follow the behaviour of 
each pair of characters in the offspring separately. 
The result of the meeting between the two opposed 
characters of the same pair we saw to be different in 
different cases. There may arise in the offspring 
(1) the appearance of a simple blend of the two parental 
characters. Or (2) one character may be more or less 
dominant over the other. Or (3) the combination of 
the two parental characters in the offspring may give 
rise to an appearance quite different from that of either 
of them, very much in the same way as in chemistry 
oxygen and hydrogen when combined give rise to water. 
Or (4) we may get further complications in which un- 
suspected characters, present in an invisible condition 
in one or both parents, take a part, often giving rise 
to the appearance of a supposed reversion. 
The most important phenomenon of all, however, 
is that which is found to occur at the formation of the 
germ cells of the heterozgyote plant or animal. What- 
ever the appearance of the hybrid form may have been, 
at this stage in its history the determining factors for 
each member of the pair of parental allelomorphs 
reappear in their entirety in certain cells which by 
their division give rise to the gametes, and at one 
of the divisions in question the parental characters (in 
a potential condition) separate completely from one 
another, so that half the gametes bear one allelomorph 
and half of them the other. In cases where more than 
