se seen in
all ordinary cases of Reversion; but before discussing this subject it may
be advisable to say a few words on those characters which I have called
latent, and which would not be classed under Reversion in its usual sense.
Most, or perhaps all, the secondary characters, which appertain to one sex,
lie dormant in the other sex; that is, gemmules capable of development into
the secondary male sexual characters are included within the female; and
conversely female characters in the male. Why in the female, when her
ovaria become diseased or fail to act, certain masculine gemmules become
developed, we do not clearly know, any more than why when a young bull is
castrated his horns continue growing until they almost resemble those of a
cow; or why, when a stag is castrated, the gemmules derived from the
antlers of his progenitors quite fail to be developed. But in many cases,
with variable organic beings, the mutual affinities of the cells and
gemmules become modified, so that parts are transposed or multiplied; and
it would appear that a slight change in the constitution of an animal, in
connection with the state of the reproductive organs, leads to changed
affinities in the tissues of various parts of the body. Thus, when male
animals first arrive at puberty, and subsequently during each recurrent
season, certain cells or parts acquire an affinity for certain gemmules,
which become developed into the secondary masculine characters; but if the
reproductive organs be destroyed, or even temporarily disturbed by changed
conditions, these affinities are not excited. Nevertheless, the male,
before he arrives at puberty, and during the season when the species does
not breed, must include the proper gemmules in a latent state. The curious
case formerly given of a Hen which assumed the masculine characters, not of
her own breed but of a remote progenitor, illustrates the connexion between
latent sexual characters and ordinary reversion. With those animals and
plants which habitually produce several forms, as with certain butterflies
described by Mr. Wallace, in which three female forms and {400} the male
exist, or as with the trimorphic species of Lythrum and Oxalis, gemmules
capable of reproducing several widely-different forms must be latent in
each individual.

The same principle of the latency of certain characters, combined with the
transposition of organs, may be applied to those singular cases of
butterflies and othe