408 Hereditary Transmission of Stature in Horses. [July, 
3. In those cases in which the stature of the father far 
exceeds that of the mother, the female descendants 
will be larger than the mother, but smaller if the 
father is only little larger than the mother, of equal 
size, or smaller. 
4. The mean size of the female offspring of two parents 
of equal stature, whether of the same race or of 
different races, is generally a little smaller than that 
of the parents. The reason is that in those cases 
in which the female offspring exceeds the stature of 
of its parents, the difference is smaller than when it 
falls below them. The number of cases, however, in 
which the female descendant respectively surpasses 
or falls short of the stature of the parents is approx- 
imately equal. 
5. When the size of female descendants is determined by 
the father, this happens most commonly in crossings 
in which the father belongs to the English blood or 
half-blood race. In all other races which have come 
under our observations no especial influence is per- 
ceptible, but it is perfectly indifferent to which race 
the father or the mother belongs. 
6. In crossing English blood stallions with Arabian mares 
the female offspring produced almost exclusively ex- 
ceeds the mean stature of the parents. On crossing 
the same stallions with Norman mares the reverse is 
the case. 
7. In all the above-mentioned points exceptions are not 
rare, so that no simple rule can be given for pre- 
dicting the stature of female posterity in horses. 
As regards the factors which determine sex, Dtising lays 
down the following conclusions : — 
Fiquet had observed in cattle the faCt that animals whose 
sexual powers are called into more frequent requisition pro- 
duce more individuals of their own sex. Dtising ascribes 
this result to the circumstance that in males in such cases 
the semen secreted comes quickly into requisition, and 
fecundation is therefore effected by means of relatively 
young spermatozoa. 
Hence more male young are produced, whilst a sexually 
inactive male begets more female young, on account of the 
greater age of the spermatozoa. It follows that the greater 
the want of individuals of one sex, the greater demand is 
made upon those already existing, the more rapidly their 
sexual products are used up, and the more individuals of the 
