support the conclusion that the condition is the effect of certain
mechanical strains, and is of somatic origin, while the correlations here
reviewed are entirely unexplained by any theory of mutation or blastogenic
origin.


OPPOSING EVIDENCE

We have now to review certain cases which seem to support conclusions
contrary to those which we have maintained in the preceding pages, and to
consider the evidence which has been published in support of other
theories. It must be admitted that the occurrence of male secondary
characteristics on one side of the body, and female on the other, is in
consistent with the view that the development of such characters is due to
the stimulus of a hormone, since the idea of a hormone means something
which diffuses by way of the blood-vessels, lymph-vessels, and interstices
of the tissues, throughout the body, and the hormone theory of secondary
sexual characters assumes that these characters are potentially present by
heredity in both sexes. The occurrence of male somatic characters on one
side or in some part of the body and female on the other, usually
associated with the corresponding gonads, has been termed
gynandromorphism, and has long been known in insects. Cases of this
condition have been observed, though much more rarely, in Vertebrates. I
am not aware of any authentic instances in Mammals, and the supposition
that in stags reduction or abnormality of one antler may be the result of
removal or injury to the testis of one side, or the opposite, have been
completely disproved by experiments in which unilateral castration has
been carried out without any effect on the antlers at all. In birds,
however, a few cases have been recorded by competent observers with a
definiteness of detail which leaves no possibility of doubt. One of the