Variation and Heredity 285 
25 per cent recessive egg-cells; while the remaining 50 per 
cent of each kind would meet each other. Or, as Mendel 
showed by the following scheme : — 
A SS a 
A A a a 
Or more simply by this scheme : — 
A a 
Lt 
Mendel’s results have received confirmation by a number of 
more recent workers, and while in some cases the results 
appear to be complicated by other factors, yet there can 
remain little doubt that Mendel has discovered one of the 
fundamental laws of heredity. 
It has been found that there are some cases in which the 
sort of inheritance postulated by Mendel’s law does not seem 
to hold, and, in fact, Mendel himself spoke of such cases. 
He found that some kinds of hybrids do not break up in 
later generations into the parent forms. He also points out 
that in cases of discontinuity the variations in each character 
must be separately regarded. In most experiments in cross- 
ing, forms are chosen which differ from each other in a 
multitude of characters, some of which are continuous and 
others discontinuous, some capable of blending with their 
contraries while others are not. The observer in attempting 
to discover any regularity is confused by the complications 
thus introduced. Mendel’s law could only appear in such 
cases by the use of an overwhelming number of examples 
which are beyond the possibilities of experiment.! 
Let us now examine the bearing of these discoveries on 
Pollen-cells 
Egg-cells 
1 This statement is largely taken from Bateson’s book. 
