my she would erect her hackles and show
fight. Thus every character, even to the instinct and manner of fighting,
must have lain dormant in this hen as long as her ovaria continued to act.
The females of two kinds of deer, when old, have been known to acquire
horns; and, as Hunter has remarked, we see something of an analogous nature
in the human species.

On the other hand, with male animals, it is notorious that the secondary
sexual characters are more or less completely lost when they are subjected
to castration. Thus, if the operation be performed on a young cock, he
never, as Yarrell states, crows {52} again; the comb, wattles, and spurs do
not grow to their full size, and the hackles assume an intermediate
appearance between true hackles and the feathers of the hen. Cases are
recorded of confinement alone causing analogous results. But characters
properly confined to the female are likewise acquired; the capon takes to
sitting on eggs, and will bring up chickens; and what is more curious, the
utterly sterile male hybrids from the pheasant and the fowl act in the same
manner, "their delight being to watch when the hens leave their nests, and
to take on themselves the office of a sitter."[119] That admirable observer
Reaumur[120] asserts that a cock, by being long confined in solitude and
darkness, can be taught to take charge of young chickens; he then utters a
peculiar cry, and retains during his whole life this newly acquired
maternal instinct. The many well-ascertained cases of various male mammals
giving milk, show that their rudimentary mammary glands retain this
capacity in a latent condition.

We thus see that in many, probably in all cases, the secondary characters
of each sex lie dormant or latent in the opposite sex, ready to be evolved
under peculiar circumstances. We can thus understand how, for instance, it
is possible for a good milking cow to transmit her good qualities through
her male offspring to future generations; for we may confidently believe
that these qualities are present, though latent, in the males of each
generation. So it is with the game-cock, who can transmit his superiority
in courage and vigour through his female to his male offspring; and with
man it is known [121] that diseases, such as hydrocele, necessarily
confined to the male sex, can be transmitted through the female to the
grandson. Such cases as these offer, as was remarked at the commencement of
this chapter, the simplest