Yorkville enquirer. [volume] (Yorkville, S.C.) 1855-2006, 1866-11-15
fumer's Reaatng,
From the Rural Southemer.
Important to Stock-Breeders.
PRODUCTION OF SEXES AT WILL.

What are the causes of the production OF
the sexes? This question which has occu-
pied the earnest attention of psychologists
from the remotest antiquity, has been thor,
oughly studied by Prof. Thury, of Geneva
The Swiss naturalist has demonstrated the
important law in relation to the production
Of the sexes; viz: "That the product is
always of the male sex when the fertiliza-
tion of the ova occurs at complete maturi-
ty, and is always female when it takes place
at less advanced period"
M. ThurY has shown that the same law
applies to the production of the sexes in
plants; thus proving that it is fundamen'
tai law, applicable to organized beings
With regard to plants, it is only necessary
to state, that by the management of the in
fuence of external agents, the observer is
enabled to produce the development of
either one or the other sex Such obser-
vations prove that the development of the
male sex is always related to those general
causes which induce a more complete ma
turation of the juices and more perfect de-
velopment of the organs of the plant.
This fundamental fact M. Thury applies
to the animal kingdom. 1t remained to
fix the precise moment at which this pri-
mary determination of the sex takes place.
This might be before formulation, or during,
or after this act. According to the expert
ments of Thury, the primary determination
of the sex precedes the act of formulation.
There is very simple way of testing the
truth of Thury's law. 1t is to select for ex.
pertinent species whose ova come to ma.
turity in succession, and that during sim
gle impregnatiou fertilize the whole series of
ova which detach themselves from the ovary
during a succession of days. We know, in.
deed, that, in case of the hen, single
coupling sufices for the fertilization of s.,
6 or eggs, which it is about to lay, and
which are arranged in her ovary in the or
der of their maturation. Now, in such a
case, if the theory is true, the first eggs
laid ought to produce males, and the other
females. This factin regard to hens seems
to be established by the experiments of NJ.
NJ. Coste and Gerbe.
In confirmation of the views of Thury,
NJ. Florens, of the Academy of Sciences,
of Paris, recalled an experiment which he
had made thirty years ago. Aristotle had
observed that the pigeon ordinarily lays
two eggs, and that one of them commonly
produces a male and the other female
NJ Flourens wished to ascertain which Of
the eggs gave the male and which the fe-
male. He found that the first laid egg al
ways gave the male, and the second the fe-
male. He repeated this experiment eleven
times in succession, and eleven times in
succession the first egg gave the male, and
the second egg the female.
1t was easy to apply the preceding law
to the uniparous mammalia. In these the
ovam separates from the ovary at the COM
mencement of the rutting season, and it
may be formulated at any time during the
whole period that the female continues in
heat, and consequently when its matura'
ton or development is more or less ad.
vanced. If the formulation takes place at
the commencement of the period of heat, a
female is the result; if at the end of this
period, male.
According to Thury, the life of the un-
fecundated ovum is diVisible into two pc.
RODS: In the first of these it is, in princi.
pie, female ovum, in second, male ovum.
The relative duration of these two periods,
he suggests, may be modified by the organic
state of the female; whence would result a
predispostiion in some females to give birth
to one or the other sex. 1t will be remarked
that the theory excludes the male from all
direct agency in the production of the sex
es this being determined prior to fecunda-
tion.
We subjoin M. Thury's "Summary and
Practical Observations p
l. Sex depends Oh the degree of matura-
tion of the ovum at the moment of its fecun-
dation.
2. The ovum which has not attained
certain degree of maturation, if it be fecun-
dated, produces female; when this degree
of maturation is passed, the ovum, if fecun-
dated nrodnces a male.
8. When, at the ruttiug season, single
ovum separates from the oVary to descend
slowly through the genital canal, Gas in
uuiparous animals it is sufficient that the
formulation takes place at the commence.
ment of the rutting season, to produce fe-
males, and at the end, to produce males
4. When several ova separate successive.
ly from the ovary during single genera
tive period, Gas in oviparous and multipa-
rous auimals,) the first ova are generally
least developed, and produce females the
last are more mature, and furnish males-
But it is obvious that the application of the
law of sexuality is less easy and more un-
certain in the case of multiparous animals.
5. In the application of the law to the
larger mammalia, it is necessary that the
experimenter should observe the course of
the phenomena of heat in the very individ-
ual upon which he proposes to act, in order
that he may know exactly the duration and
signs of the rutting season this varies in
different individuals.
8. No certain result can be expected
when the signs Of heat are vague or equivo