e, and confine ourselves to observing the inheritance of the single
characteristic, plumage _color_. Of course, as long as the black mate
only with the black their children will be black, and as long as the
white mate with white the children will be white. But if a white mates
with a black, the children will not be either black or white, but blue.
All will be blue. But the most interesting facts appear in the next
generation, when these hybrid blue fowls mate with black or white, or
with each other. The original of the cross between the white and the
black is an entirely new color blue, which may be considered a sort of
amalgam of black and white. But a cross between the blue and the black
will not be any new color, but will be either black or blue--and the
chances are even. That is, in the long run about half of the children
of the blue and black parents will be blue and half will be black. None
of the children will be white. So also crossing the blue with the white
will result in half of the children being blue and half, white. Still
more curious is the result of mating blue with blue. One might imagine
that in this case all the children would be blue, but only half will be
blue, while a quarter will be black and a quarter white.

[Sidenote: Laws of Chance]

These laws are a curious mixture of chance and certainty. In certain
circumstances, as we have seen, we can predict with certainty that the
offspring will be black, white, blue, or whatever the case may be. In
other circumstances we can only state what the _chances_ are. But these
chances can be definitely stated as one in two, one in four or whatever
it may be, and where there are large numbers of offspring this amounts
to a practical certainty that definite proportions will have this or
that color, or other characteristics.

Two parents are like two baskets or bundles of traits from which the
child takes its traits at random. In the wonderful play of
Maeterlinck's, called the "Bluebird," we are taken to the "land before
birth," where the children are waiting to be born, having selected
their parents to be. Of course, this is only a pleasant fancy, like the
advice of Oliver Wendell Holmes to children to choose good grandparents,
but it is a useful fancy which will help us to understand the laws of
heredity. The child of the Andalusian fowl takes its color from its two
parents on the same principle as a lottery in which it would take two
beans, white or black as