The Indianapolis times. [volume] (Indianapolis [Ind.]) 1922-1965, 1934-07-02
SEX CONTROL is
ACCOMPLISHED
IN |, U. TESTS
State Scientists Successful
in Experiments With
Baby Chicks.
Copyright. 1888. BY Science servicel


BLOOMINGTON, Ind. july a.
One of the first apparently success
full attempts at experimental sex
control Of warm FLOODED animals
has just been reported here from
the Indiana university geological
Laboratories.
Through injection and absorption
Of female sex hormoneS into more
than 900 chick embryos, expert
mentors have been able to change
the normal sex ratio Of about so per
cent females to 64.78 per cent
females. With more complete con-
troll Of experimental conditions, it
seems possible theoretically to con-
troll almost without exception the
sex of the embryos.
This means sex reversal from
male to female through artificial
control. The next step in the ex-
pertinent will be to attempt the
more difficult change from female
to male.
The possibility of experimental
sex control long has been a subject
of scientific investigation. Sex re-
versal has been accomplished ex-
perimentally in the amphibianS and
other cold looded animals but has
baffled science in its efforts on
warm blooded species, although
Professor F. A. E. Grew Of the Uni
versity of Edinburgh has reported a
female fowl which laid eggs and
later produced sperm.
Two Years of Work
Working for the past two years
on the general problem Of the effect
of endocrine gland preparations on
the development of the chick en-
byro. Indiana university investiga-
tors developed theory of sex con-
troll injection of sex hormoneS.
They took advantage of the
known fact that the gonads or sex
glands of the chick embryo are
practically ident so far as
structure is conc oed until about
the sixth day development. At
that time, sex differentiation occurs.
Injection of hormones was started
on the third or fourth day, when
theoretically the gonad could be
changed. The extract was inserted
into the air chamber at the large
end of the egg. Absorption was &C
complished through the allantois of
the embryo, a vascular membrane
which takes up the extract.
The heavy percentage of females
developing from the artificially
treated embryos, as compared with
the normal $3.50 ratio, seems in
dicative if not proof of sex re-
versal. In answering the question
of why the 900 embryos Of the ex-
pertinent showed any males at all, it
is explained that the allantois or
absorbing tissue of many males de-
velops so late that the extract Of
female hormoneS is not absorbed
under the present experimental
methods.
Shell Membranes Dry
Another reason for failure to
bring about complete sex reversal is
that the shell membranes in many
cases are SO dry as to absorb all of
the extract before it reaches the
allantoiS of the embryo With COM
plete control of experimental con-
ditions, it should be theoretically
possible to effect a complete sex re-
verSal.
In normal development, sex is
thought to be determined by the
presence of certain definite bodies
called chromosomes, within the cells
of the individual. A definite chrom-
osonne difference exists between the
male and female sexes, but just how
the chromosomes produce their
effects is unknown. Granted thai
the chromosomes do play part in
sex differentiation, such effects are
not wholly independent of environ
mental conditions.
Continuing the injections after
sex differentiation has taken place
in the chick embryo, eXperimenters
have found that the extract of fe-
male hormones produce an abnor-
mality in the male glands, but that
the change is not sufficient to pro-
duce reversal, once sex diferentia-
ton has definitely developed.