Evening star., 1937-12-05
CARNEGIE EXHIBIT
7O0PEN NSATURDAY
Outstanding Discoveries OF
Year to Be Displayed
for First Time.

Scientific discoveries Of outstanding
importance during the last year by
research workers OF the Carnegie
shown for the first time at the annual
exhibition next Saturday, Sunday and
Monday.
Notable among the developments to
be shown because of its far-reaching
practical possibilities is the expert
mental "chromosome doubling" ac-
complished by the institutions genetic
laboratory.
Chromosomes are the rod-like bodies
genes, or units of heredity. These
chromosomes are passed from parent
to offspring in both plants and ami
mails. They are responsible for race
and species. Ordinarily they are very
stable, passing from generation to
generation unchanged. When there
Is a change a new species may come
into existence, although usually such
changes result in the death of the
individual before it has an opportunity
to reproduce itself.
Favorable Change.
Many observations in the past have
shown that the doubling of the num-
Der of chromosomes usually is
favorable change. 1t appears to have
been one of the chief mechanisms of
evolution in nature. 1t is responsible
for the origin of large proportion of
domestic fruits and flowers and for
their superiority over their wild an
cestors. 1t increases the size of the
organs of the plant and is known to
have changed self-sterile to a self
fertile form, and an annual plant to
a perennial It also has increased
winter hardness.
desirable new species by chromosome
doubling has been a matter of acci-
dent. This year Carnegie research
workers found it can be induced in a
large number of cases by using a very
virulent poison, the alkaloid colchicine,
which is extracted from Seeds of the
autumn crocus.
OF this poison before planting, or
drops may be applied to buds or a
solution sprayed over the plant. It
may also be mixed with lanolin, the
basis OF cold cream, and applied to
the bud as salve.
The first effect is that of virulent
poison. Growth OF the plant is
checked. The stem becomes swollen
and the leaves roughened Gradually
the plant recovers from this condi-
ton. In great number of cases the
cell chromosomes are somehow dou-
bled in the process. More than half
the Older plants of one variety pro-
duced branches with double chromo-
some flowers, and all the seedlings
from treated seeds showed the same
effect
Evolution Elixir.
Cochicine seems, as far as plants
are concerned. q veritable "evolu-
ton elixir" How it can be applied
to animals is dificult to see at pres
ent. But one OF the great difIicul-
ties in breeding desirable species Of
plants In the past has been the failure
to get fertile hybrids. When two
varieties with individual desirable
characters are crossed the good quail
ties Of both parents may appear in
the immediate seedlings, but these
themselves will not produce fertile
seeds needed to carry on the line. Al
ready, 1t Is announced, it has been
possible to produce a more vigorous
species of tobacco from two parent
species the crosses of which hitherto
have been sterile
A notable development during the
year was the discovery of the oldest
known animal fossil. The story of
animal life, as told by imprints in the
rocks, hitherto has gone back about a
half billion years, to the so-called
early Cambrian geological epoch. In
rocks dating from that period are
found imprints Of variety of ami
mails. chiefly crustaceans roughly re-
sembling crabs. These creatures stand
at the very frontier OF known life.
Highly Specialized.
Earlier rocks have shown no indis-
putable trace Of animal life. And
yet the ancient crabs themselves were
highly specialized creatures who must
have had long line Of evolution be-
hind them. They were much further
away from any possible beginning of
life than human beings are from crabs.
Only dubious remains of plants even
have been recovered from the pre-
Cambrian rock formations.
Now, 1t is announced, Carnegie sci
entists have found far back in the
pre- e-Cambrian, in a Grand Canyon