Evening star. [volume] (Washington, D.C.) 1854-1972, 1909-12-05
By w. A. Du Puy


| animal or vegetable, there is
| law of heredlty that is everywhere the same
This law sets down in definite figures the quail
ties of each parent that will appear in the off
spring in the first the second, the third, and all
| the generations that follow. The existence of
| such a law has long been suspected; but it has
| remained for the Government, after years Of
investigation, to declare it fact and place back
| of it the weight of its authorized scientists
Gregor Mendel, an Austrian monk, fifty
years ago was pottering about his clustered
garden and breeding plants together that had
strange and distinctive characteristics. The
peculiarities of the generations that followed
certain crosses and their repetition in mathe-
| NAUTICAL accuracy, led him to lay down law
that has since borne his name and made him
famous wherever scientists talk Of heredity.
Mendel held that where two strongly con-
trasting strains were crossed, one would be
likely to prove itself dominant. The resulting
first generation of offspring would all be like
the dominant strain. Members OF this genera
ton would beget offspring three-fourthS of
which would follow the dominant strain; but
one-fourth would react to the weaker grand
parent and show the characteristics of that
member that had appeared absolutely absent
in the first generation. In the third generation
these characteristics of the weaker member
would reappear in the descendants of those
that had shown it in the second, and remain
fixed, reproducing themselves indefinitely. So
would the characteristics of twenty-five per
cent. of the dominant strain IN this generation
become fixed This would leave an unfixed
fifty per cent. that would breed another genera
ton with the characteristics partly fixed and
partly unfixed and in the same proportions as
the previous generation. All the generations
that followed from this unhxed division would
be like the third generation In their character
istics and their proportions.
Since the time of Mendel other scientists have
checked the law back and forth and found it to
their liking; but it remained for this Govern
ment to give the greatest demonstration of
them all and finally set upon it the seal of its
approval This it has done, and in rather an
odd way.
At Bethesda, in the outskirts of Washington,
is located the experiment station of the Bureau
of Animal Industry Department of Agricul-
cations of the Government The proving OF
the correctness Of the Mendel law IS part
of these.
Experiments with Rats
FINDER the direction of DR.. E. c. Schroeder
- rats were selected as the objects for these
particular experiments. There were the two
plainly marked members of the rat family, the
plain gray and the hooded. The first of these
was of solid color, and the second was white
with black head. The colors were the distinc-
tive points. 1t was no trouble to tell which of
the parents the offspring resembled.
Of the first generation resulting from this
cross every member was solidly gray like the
dominant strain of the parents. This was as
Mendel said it would be. :. Two members of this
generation were crossed, not necessarily
brothers and sisters, as other lines had been
gray rats of the first generation produced part
gray and part hooded The hooded rat that
had failed to make itself felt in the first genera
ton showed in twenty-five per cent. OF the
second These hooded rats bred hooded in the
following generations. A portion of the grays,