410 
Dl D. FÉNYES 
the probable hereditary ratio of the dominant and recessive properties 
in the given cases, can be estimated beforehand. 
Uniformity — namely the absence of vari¬ 
ation — in the first generation, cannot be separat¬ 
ed from the dominance. The closer the relation¬ 
ship between the breeds intended to be crossed, 
or the greater the preponderance of the similar 
properties of the ancestors, compared to the diffe¬ 
rent properties, the greater will be the dominance, 
and consequently, the smaller the variation; and 
vice versa —the more remote the relationship, the 
more different the properties of the ancestry, the 
smaller will be the dominance, and the greater the 
variation. This connection is proved by the general experience, that 
the proper Mendelian ratios are approached by the hybrids of the variety - 
or race — crosses only ; while the hybrids produced by the crosses between 
subspecies, species, subgenera, and genera respectively, show successivly 
longer series of variations. 
If the breeds intended to be ciossed are related, or their ancestry 
had similar properties, dominance will appear, i. e\, the first hybrid gene¬ 
ration will be uniform, while, in the second and following generations,, 
different types will be shown by the offspring. If, on the other hand, the 
breeds intended to be crossed are not related, or their predecessors had 
different properties, there is no dominance, no uniformity, and, already 
in the first hybrid generation, a series of different types will appear. In the 
grade of the relationship, or in the grade of the similarity of the ancestral 
properties, lies, the cause proxima tly also, that the variation of the offspring 
will show a continuous or discontinuous series respectively. 
According to Mendel’s Principles, — in consequence of a cross, there 
will appear, *in the second, and following generations, besides the hetero- 
zygots, homozygots also, viz., descendants, which breed true, which are 
of the same value as the pure grandpaternal and grandmaternal breeds 
respectively ; the extreme variations through the successive generations 
remain the same, and equal to the difference between the pure-bred 
ancestors. The characters of the hétérozygotie descendants, which eventually 
come midway between the pure breeds, will never be fixed, which means, 
that the breeds crossed will never produce new (intermediate) breeds, but 
their offspring will always return to the original pure breeds. This suppo¬ 
sition can easily be supported by the — now obsolete — doctrine of the 
constancy of species, but no interpretation could bring it in accordance 
with the idea of evolution, and less so with facts. The hybrids supposed 
