The Descent of Man

progenitors.), and possibly with the Ainos, who
inhabit the northern islands of the Japan archipelago.
But the laws of inheritance are so complex
that we can seldom understand their action.
If the greater hairiness of certain races be
the result of reversion, unchecked by any form
of selection, its extreme variability, even within
the limits of the same race, ceases to be remarkable.
(24. Hardly any view advanced in this
work has met with so much disfavour (see for
instance, Sprengel, 'Die Fortschritte des Darwinismus,'
1874, p. 80) as the above explanation of
the loss of hair in mankind through sexual selection;
but none of the opposed arguments
seem to me of much weight, in comparison
with the facts shewing that the nudity of the
skin is to a certain extent a secondary sexual
character in man and in some of the Quadrumana.)
With respect to the beard in man, if we turn to
our best guide, the Quadrumana, we find