284 Evolution and Adaptation 
with the pollen plant. From this we may conclude that, if two 
varieties differing in a large number of characters are crossed, 
the hybrid might get some of its dominant characters from 
one parent, and other dominant characters from the other 
parent, so that, unless the individual characters themselves 
were studied, it might appear that the hybrids are interme- 
diate between the two parents, while in reality they are only 
combinations of the dominant characters of the two forms. 
But even this is not the whole question. 
Mendel points out that, from knowing the characters of 
the two parent forms (or varieties), one could not prophesy 
what the hybrid would be like without making the actual 
trial. Which of the characters of the two parent forms 
will be the dominant ones, and which recessive, can only be 
determined by experiment. Moreover, the hybrid characters 
are something peculiar to the hybrid itself, and to itself alone, 
and not simply the combination of the characters of the two 
forms. Thus in one case a hybrid from a tall and a short 
variety of pea was even taller than the taller parent variety. 
Bateson lays much emphasis on this point, believing it to be 
an important consideration in all questions relating to hybri- 
dization and inheritance. , 
The theoretical interpretation that Mendel has put upon 
his results is so extremely simple that there can be little 
doubt that he has hit on the real explanation. The results 
can be accounted for if we suppose that the hybrid pro- 
duces egg-cells and pollen-cells, each of which is the bearer 
of only one of the alternative characters, dominant or reces- 
sive as the case may be. If this is the case, and if on an 
average there are the same number of egg-cells and pollen- 
cells, having one or the other of these kinds of characters, 
then on a random assortment meeting of egg-cells and 
pollen-cells, Mendel’s law would follow. For, 25 per cent of 
dominant pollen grains would meet with 25 per cent dominant 
egg-cells; 25 per cent recessive pollen grains would meet with 
