The Descent of Man

failed to produce offspring. During 1867, 836
males and 902 females were born, and 794 mares
failed.), consisting of 12,763 males and
12,797 females, or in the proportion of 99.7 males
to 100 females. As these numbers are tolerably
large, and as they are drawn from all parts
of England, during several years, we may with
much confidence conclude that with the domestic
horse, or at least with the race-horse, the
two sexes are produced in almost equal numbers.
The fluctuations in the proportions during
successive years are closely like those which
occur with mankind, when a small and thinlypopulated
area is considered; thus in 1856 the
male horses were as 107.1, and in 1867 as only
92.6 to 100 females. In the tabulated returns the
proportions vary in cycles, for the males exceeded
the females during six successive years;
and the females exceeded the males during two
periods each of four years; this, however, may
be accidental; at least I can detect nothing of the