MENDEL’S LAW 231 
excessive size of the comb and its becoming frosted, the produc- 
tivity of the individuals was impaired. He desired to remedy this 
by replacing the single comb with a pea comb, but in order to do 
this it would be necessary to cross his birds with Indian Games 
possessing finely developed pea combs. The pea-comb trait 
would be fixed in the early generations, since this is a dominant 
character. It would require, however, many generations of breed- 
ing and selection to eliminate the color pattern which was brought 
into the flock by the intermixture of the game blood. 
In a study of characters which may possibly result from hybrid- 
izing and the frequency of their occurrence, knowledge of Mendel’s 
law will be helpful. 
Mendel’s Law.—Mendel’s law states that, when crossed forms 
or hybrids are bred together the opposing characters possessed 
by the original parents tend to combine in definite proportion. 
The offspring from such hybrid individuals (AB) will assume the 
algebraic form A?+2 AB+B?. In the formula A represents one 
of the contrasting characters, while B represents the opposite 
trait. This formula means, in numbers, that, out of every 100 
chicks resulting from a cross, twenty-five will possess one of the 
characters, or will be pure A, twenty-five will be pure B, while 
the remaining fifty (represented by the figures 2 AB) will be a 
mixture of the two opposing characters. 
Mendel’s law also states that where there is a pair of contrast- 
ing characters,—for example, single comb and rose comb,—one 
will be dominant over the other, the result being that a majority 
of the progeny will show this dominant character. The other 
opposing character is termed recessive, for it recedes from view in 
the presence of the stronger or more prominent one. Dominance 
of a character does not imply that the recessive one is absent, 
but simply that in the development of the new individual the 
dominant character is bound to appear. A pigmented condition 
of the plumage is dominant over absence of pigment; an extra 
toe is dominant over a normal number; feathers on the shanks 
are dominant over their absence, the rose comb over the single 
comb, and so on through a great variety of characters. Only one 
pair of contrasting characters is to be considered at any one time. 
This second phase of Mendel’s law may be expressed by the fol- 
lowing formula: 
D?+2 Dr+R? 
M+ri4 + 
