408 
Dì D. FÉNYES 
The characteristic of this cross is the grey (dominant) : white (reces¬ 
sive) = 3:1 Mendelian ratio, which can be deduced from the 
pedigree. 
ß) The cross between pure-bred white and pure-bred black is shown 
by the following pedigree: 
grey grey 
* Ï ! 
white X black 
The characteristic of this cross is the white (recessive) : grey (domi¬ 
nant) : black (recessive) =1:2:1 Mendelian ratio, which can be de¬ 
duced from the pedigree-. 
These two Mendelian ratios can present themselves precisely, in such 
cases only, when white, grey and black are quantities of equal measure. 
When, on the other hand, white ^ grey, grey ^ black, and white ^ black, 
the ratio must change, and there is plenty of opportunity to observe 
this. «The hereditary ratio» is, conseque n t by, not 
fixed, but k e e p s c h a n g i n g in each case, according 
to the nature of the cases, according to the pe¬ 
di g r e e, a n d is c h a r a c t e r i s t i c of the single cases 
o n 1 y. The fig. 5, 1 2 3 referred to here, shows the series of the possible ratios 
of the dominant and recessive properties, which can be expressed in quarters. 
The phenomenon of dominance is to be ex¬ 
plained thus, that, in consequence of across, simi¬ 
lar properties in e e t, and so far as they re p resent 
then a majority over the different properties, 
1 Fig. 5. (See pag. 390.) — The Table of Dominance. 
Examples: 0x3. — The deduction of the ratio: 
4 greys + 
2 greys -}- 2 whites 
6 greys : 2 whites =3:1. 
3 x4. — The deduction of the ratio : 
2 whites -f- 2 greys + 
+ 2 greys + 2 blacks 
2 whites : 4 greys : 2 whites = 1:2:1. 
1x6, — The deduction of the ratio : 
3 w'hites + 1 grey + 
-f- 3 greys 4- 1 black 
3 whites : 4 greys : 1 black = 3:4:1. 
