142 DOMESTICATED ANIMALS AND PLANTS 
the blood of a three-fourths white bred with a seven-eighths white 
8 F sec ; 
would be aT or 13 white with the remaining ;°; yellow, — 
this much for single kernels or for a whole generation of known 
mixed breeding. 
Suppose now that white and yellow corn be planted together 
in the same field in equal proportions. What will be the nature 
of the crop? The answer to this question covers one of the most 
important points in plant or animal improvement, for there is 
_no essential difference in principle between the two, and what 
applies to one applies equally to the other, so far as principles 
are concerned. - 
In such a field planted equally with white and yellow corn 
the first question is, Will all the kernels be mixed? Manifestly 
not. Under the law of chance! a yellow silk, for example, will 
have equal opportunities of being fertilized by a yellow or by a 
white pollen grain ; that is to say, the ovule stands equal chances 
of developing as a pure or as a mixed kernel, and the same may 
be said of any kernel in the field, provided of course that the 
number of silks and of pollen grains are equal, as was specified 
in the problem. 
When the season is over, the whole population of corn ker- 
nels of the field will then be as follows: on the stalks arising 
from yellow kernels } will be pure yellow and } will be mixed, 
yellow and white; on the stalks arising from white kernels } 
will be pure white and } will be mixed, yellow and white. 
Now, as the corn was planted half and half, each kind of 
stalk represents half the crop. So we have for the field as 
a whole, } pure yellow; 4 mixed, white on yellow; } pure 
white ; 4 mixed, yellow on white. 
But as white pollen on yellow silk gives the same mixture as 
yellow pollen on white silk, we have our population reduced to 
the following: | pure yellow, } mixed, } pure white, from which 
1“ Principles of Breeding,” pp. 365, 504. 
