Evening star., 1922-12-20

white rats. all members Of the
same family and all Of whom once
enjoyed equal states of health. BY
feeding each rodent q specified diet
the scientists were able actually to
control the growth and ability Of
their four-legged subjects.
Differences in Weight.
One OF the rats was fed only zein
and tryptophane. which contain the
, least quantity of vitamins. Its max
| imum weight reached only 43 grams.
| and 1t did not grow to be one-half the
! size Of a brother rat whose diet had
been wheat flour and meat The lat
ter proved to be the healthiest Of the
nine. reaching a maximum weight Of
| BIB grams. A third rat was fed only
| wheat Hour and eggs, but although 1t
| looked to be very much healthier and
fatter than the meat-fed rodent, its
weight was only 304 grams.
| A callrometer. one of the few in the
world. also is on view. This is an in
| strument which measures the precise
amount OF oxygen consumed by a man
| though it was originally intended
only for use in research work. sur
geons have found 1t highly efficient
for use during an operation. because
1t enables them to keep a patient sup
piled with the exact amount of oxygen
| necessary to sustain his life while on
| the operating table.
Remarkable Astronomy Display.
| The astronomical exhibition is little
less than marvellous. In it are actual
photographs showing the volcanoes of
! the moon and the arrangement of tho
/ ri II Nd cto IN,
heavens. For instance, there is dis
play proving that in the course of
| perhaps 10000 years the group
| known as the Big Dipper will entirely
! disappear. Astronomers have found
| ample proof that it did not exist
$50 years ago. and that its various
| units are moving off in opposite di-
| rections. Mars and Saturn are
brought SO close in the photographs
p, that it Is possible to see what appear
| to be great continents on their sur
| faces.
| Another department shows speci-
mems of trees that were growing in
America the year Christ was born.
and other trees 80 old that they had
been buried by tons of dirt. By means
| of these trees the scientists explain
| how they can tell US just what kinds
| of a climate existed here during the
years of their growth, whether 1t was
a rainy year or a very dry one. The
rings. or grain, as the layman knows
1 them. tell this story in unmistakable
language.
| Buttercup Father of Flowers.
| The genealogy OF the flowers is on
view. 1t shows the humble buttercup
to be the father Of all flowers, with
! the rose, lily and geranium as its
! earliest offspring. From these four
grew all OF the varieties of flowers
that inhabit this planet today. with
| insects and the wind guiding their
future destinies with the utmost de-
! gree of certainty.
There are score more interesting
exhibits. each one Of which tells a story
of the utmost importance to mankind.
| The exhibition originally was brought
, here solely for the benefit Of tho diroc-
/ tors of the Carnegie institution who re-
! Gently heK their annual meeting. It
was considered Of such scientific inn
portance. however. that the directors re-
quest those in charge to remain in
Washington another week and invite the
public to a view. The exhibit will be
open to all persons from o'clock until
8 o'clock this afternoon and tomorrow
afternoon.