Experimental Hybridizing gl 
some of the descendants, if these albinos are crossed with colored 
types. Thus if an albino AG be crossed with an albino AB, 
the albino offspring will be AGAB. Its germ-cells will separate 
into AG and AB, but these are albinos. If, on the other hand, 
a black-mouse, CB, be mated with an albino AY, containing 
yellow as a latent character, the offspring will be CBAY (yel- 
low), whose germ-cells will be of four kinds, CB, AY, CY, and 
AB. Crossing this yellow mouse (with its four kinds of germ- 
cells) with a white mouse, AGAB, obtained in the way just 
described, eight possible combinations may follow. The whole 
process is indicated in the following table: — 
Parenis AG (albino) AB (albino) CB (black) AY (yellow) 
1st generation AGAB (albino) CBAY (yellow) 
* 
L i \ 
AGCB gray (one) 
ABCB black (one) 
; AGAY 
2d generation eee { albinos (four) 
ABAB } 
CYAG } 
CYAB} yellow (two) 
Cuénot performed this experiment and obtained in the sec- 
ond generation 151 young, distributed as follows according to 
color: — 
81 albinos, 34 yellow, 20 black, 16 gray. 
The probability according to the formula 4 +2 n+n-+n is: 
76 albinos, 38 yellow, 19 black, 19 gray. 
The agreement is so close that there can be little doubt that the 
hypothesis is substantially correct. 
Heredity oj Piebald or Spotted Varieties. — The piebald condi- 
tion is regarded by Cuénot as a special mutation, and not one 
due to crossing colored and white forms. The piebald charac- 
ter appears in crossing to be dominated by the untjorm colora- 
tion, whatever may be its tint. For example, a spotted gray- 
and-white mouse crossed by a uniformly black mouse gives a 
uniformly colored gray mouse, showing that the coupled 
