108 Experimental Zoology 
The albinos subsequently bred true; the pigmented types were 
of two kinds, — pure and hybrid. 
Gray versus Black. — When the yellow-gray Belgians were 
mated to the white Angoras, wild gray hybrids were produced. 
These, as stated above, when inbred, gave both colored and white 
offspring in Mendelian proportion, but some of the colored in- 
dividuals were black instead of gray. There were 85 grays to 
25 blacks. The grays, as stated, were like the wild gray instead 
of the yellow gray of one grandparent, although a few appeared 
to contain somewhat more yellow than the wild type. The blacks 
had no gray, but it is interesting to note that after the first molt 
a few white hairs appeared, which increased in number with each 
molt until some of the individuals resembled the silver-gray 
breeds (chinchilla). The blacks when inbred produced only 
blacks, the grays were of two kinds, — pure and hybrid. 
“The sudden appearance of the black character in the sec- 
ond generation was quite unexpected as there had been no black 
individuals in the ancestry of either of the original parents . . 
for at least eight generations, and probably many more. The fact 
that these black individuals appeared in about the proportion 
of one quarter, and bred true at once, was very significant from 
the Mendelian point of view. It suggested that the hybrid grays 
of the first generation were giving off gametes, one half of which 
contained the factor for black coat color. That it was not intro- 
duced by both is clear from the absence of black in the first gen- 
eration.”’ It could not have been introduced with the Belgians 
because these mated to black gave only grays. The black 
must, therefore, have been introduced with the albinos. Hurst 
carried out some further experiments that seemed to substantiate 
this view. One male, albino Angora mated with four black does 
produced 16 black young; but another albino female mated 
with black produced 5 black and 6 gray young. Hurst inter- 
prets these results to mean that the first albino gave off gametes 
that all carried black, while the second albino gave off gametes 
some of which carried black, others gray. When the white male 
and the white female used in these experiments were mated, only 
