The Catholic bulletin. [volume] (St. Paul, Minn.) 1911-1995, 1915-07-24

true for the male as we'll as for the
female gametes. In the process OF
Standardization of the hybrid an equal
number Of gametes will be produced
containing the two antagonistic char
acters; of the ovules, half are tall,
half dwarf: they shall meet an equal
number of pollen grains of the same
twofold character. The ovules of both
classes have an equal chance to be.
fortified by a pollen of similar or
of a different nature. When equal
characters unite, the offspring will
breed true, whether this be in the
dominant or recessive zygote. Half
of the seeds, however, will be mixed,
owing to the equality in number of the
gametes of different natures. The
numerical relation of dominants and
recessives thus becomes matter of
necessity of the intrinsic, chromosome
structure of the gametes and zygotes;
half of the former will be homozygous;
onesfourth for the dominant, one
fourth for the recessive; one-half will
be heterozygous, manifesting this
complex structure in subsequent gen.
erations.
The production of the hybrid of an
equal number of dominant and recess
sive gametes can be tested by another
series of experiments. If the hybrid
be crossed with the pure recessive,
there ought to result from this gen.
Grafton an equal number of dominants
and recessives. The dominants so
produced through Standardization
ought in this case furnish dominants
and recessives to the ratio of three
to one. Experiments have amply
proven the truth of this expectation.
Crossing of dominant with a recess
siVe is now an universally recognized
test for the purity or the mixed char
acter of a dominant. In the former
case the descendants will all bear the
dominant character; in the latter, the
offspring will consist of an equal num-
Der of dominants and recessives.
The phenomena of segregation,
which constitutes the fundamental
fact in Mendelian doctrine of heredity,
obtains not only in the most simple
cases of monohy bridism SO far con-
templated, but it holds good as well in
dyhybridism, trihybridism, etc. The
author of this new theory of heredity
formulated the law that the inheri-
lance of each pair of characters fol-
lows the same rule as monohy bridism,
and that his principle can be extended
indefinitely.
Biology teaches us that the more
complex the organization of an animal,
the longer is the period of infantile
helplessness of the offspring. The
lower the animal in the scale of or
ganization, the greater independence
| 1t shows when it comes into the world.
But throughout the whole animal king
dom the individual comes into exist
ence endowed by nature with all nerve
associations and reflex connections
which are requisite for its well-being.
Instructive actions are impressed into
the structure of its nerve-organization
the completion of the physical growth
of the tissues is alone required in or
der that these functions be executed in
the highest degree of perfection. In
stinct is an hereditary and organic en-
dowment of the animal body on the
part of nature; hence instincts are the
same in all cases and in all places;
they do not vary except within ex-
1 tremely narrow limits. In the animal,
nature is dominant, nurture is power.
less to alter functions that are part
of the inherited organization.
In man, on the other hand, nurture
predominates, because nature has not
endowed him with the necessary or.
ganization to carry on his life-work
without education and experience;
what nature failed to do must be sup
piled by instruction. Instructive &C.
tions in man are not well defined, they
are vague and do not lead, as in the
animal, to series of operations, nee
essary for the self-preservation and
propagation of the species. The in
completeness of organization renders
man incapable of receiving education
and it makes it imperative; but heredi
tary instincts make education in the
animal impossible and unnecessary
The transference of laws of heredity
from the animal to man is thus showr
to be biological error.