calls forth this perfection of femaleness is to be shown in a later
publication. By acting with Roentgen rays on the region where the ovaries
lie, Steinach and his colleague Holzknecht brought about all the symptoms
of pregnancy, development of teats and milk glands, secretion of milk, and
great growth of the uterus in all its layers.

Masculising of females was much more difficult than feminising of males
because the testicular tissue was less resistent, and could not be grafted
so easily. When it succeeded, however, degeneration of the seminal tubules
took place, with increase of the interstitial or Leydig's cells. The
vaginal opening in rats disappeared, partly or completely. The sexual
instincts became male, the animals recognised a female in heat from one
that was not, and attempted to copulate.

Steinach considers that he has proved from results that sex is not fixed
or predetermined but dependent on the puberty gland. By sex here he
obviously means the instincts and somatic characters, for sex in the first
instance, as we have already pointed out, means the difference between
ovary and testis, between ova and spermatozoa. It is difficult to accept
all Steinach's results without confirmation, especially those which show
that the feminised male is more female than the normal female. Such a
conclusion inevitably suggests that the investigator is proving too much.

The subject of the influence of hormones from the gonads is mentioned, but
not fully discussed, in a volume by Dr. Jacques Loeb, entitles _The
Organism as a Whole_. [Footnote: Putnam's Sons, 1916.] Loeb entirely omits
the problem of the _origin_ of somatic sex-characters, and fails to
perceive that the fact that such characters are dependent to a marked
degree on hormones derived from the gonads, together with their relation
to definite habits and functions connected with the behaviour of the sexes