The Middlebury register. [volume] (Middlebury, Vt.) 1850-1882, 1876-10-07
agricultural department.
CONDUCTED BY ALBERT CHAPMAN.
Theories in Breeding.

ton, with the purpose of giving pro-
visional explanation of their relations
are of the greatest value in scientific
investigation. Indeed, it is hardly
possible to make progress In science
without theorizing in regard to the mat.
ter under consideration. One of the
highest authorities on the methods Of
scientific study, lays great stress on the
imagination as means of scientific
progress. However this may be, theo
RIGS are without doubt necessary to The
student of science If he would grasp the
facts presented for his consideration
and interpret them in accordance will
the laws of nature. But when they are
erverted from their legitimate pur.
pose, and made the basis of practical
rules in art, they must be carefully ex
amined and their truthfulness tested
by the best possible methods, or they
will certainly lead to error in the prin
,iples of the art, and result in false sys
toms of practice.
The current literature of stock. breed
ing Is filled with theoretic assumptions
that have no foundation in fact, and
false applications of principles that
may present within certain limits @
possible approximation to truth-while
they cannot he safely adopted in a
wider range of conditions of greater
complexity. A probable explanation
of certain facts, made.by one writer, is
often accepted by another as cstab.
lished truth, so that in time it is quoted
rs authority without farther examina-
lon. The great progress made within
the past few years in our knowledge OF
physiological facts and principles, is
sufficient in itself to show that but lit
tie dependence can be- placed on the
theories that were most popular some
fifteen or twenty years ago. But a
small proportion of scientific theories
in regard to physiological laws have
stood the test of verification, under the
more complete and exacting methods
of modern experimental investigation.
In 1926, the Highland Society pro
posed as n subject of prize essays the
following question "Whether the
breeds of live stock connected with ag-
riculture be susceptible of the greatest
improvement from the qualities con-
spicuous in the male or from those con
spicuous in the female parent" -Four
essays were presented-one of which is
published in full in the first volume OF
the society's transactions. together with
n summary of the three others. The
first takes the position that the male
has greater influence upon the off
spring than the female, and several
eases are cited to prove the PROPOSE
ton. In most of these cases there are
evidently many other conditions that
should have an influence on the result,
so that the paternal resemblance of the
offspring can be readily accounted for
without resorting to the superstition
that the male has the greatest influ-
ence. In another ofthe essays referred
to,a number of cases are given in which
the young resembled the female parent
in the most obvious characters, and it
would not be difficult to collect many
more cases off similar kind in conflict
with the first theory, and therefore dis
proving it. 1t should not be claimed,
however, that the rcsemblances of off.
spring.to the female parent are rs nu-
merous MS those presenting resem-
blance to the male, even 1T is admit
ted that there is no preponderating in
tiuence Of sex to determine similarity,
rs the males, as rule, have a larger
number of offspring than the females,
thus giving n larger number of instan-
ceS from which to select cases of resem-
blance. Another theory closely con-
nected with this is advanced in anoth-
or of the essays-although not original
with the writer-to the effect that the
male furnishes the external characters
and the female the internal organiza-
ton. This agrees with the presump-
tons of the first theory potlced-that
the offspring resembles, in external
form and quality, the male parent, and
ii differs only in assigning n specific
influence to the female.
This theory of half-and-half trans.
mission of characters had its origin in
an assumed physiological fact, that as
the female furnished the ovum or egg
from which the embryo was developed,
the spermatic fluid of the male invested
and covered this germ, giving origin
to the external layers of the embryonic
growth. AS this assumed division of
labor in the function of procreation has
not been established in physiological
science, the theory based on it must of
course be abandoned Several other
writer's, among which are Mr.. Orion
and Mr.. Walker, have advocated the
same theory, or a slightly modified
form of it. Mr.. Walker, while claim
ing that the organism is transmitted
by halves, admits that the male may
sometimes furnish the internal organs
and the female the external
The present condition of our knowl-
edge of embryology gives no evidence
whatever of this divided transmission
of qualities by the two sexes. After
impregnatlon, the increase and devel-
opment of the embryo is a growth
made up of materials introduced from
without the embryonic mass. and cir
culated by the vessels throughout the
system, as in the more matured forms
of existence. A few illustrations will
perhaps best show the absurdity of this
theory.
Take the case of ordinary grade ami
mails, the produce of pure-bred male