Evening star., 1941-04-19
Rate Of Replacement
OF Body Gagged al
5or Years
Psychologists Report
Proteins Not as Stable
As Supposed
(See Also Story on Page A-13.)

tSee Also St0Ty on rage A-lS.J
By Staff Correspondent of The star.
CHICAGO. April ia human
being may be completely reborn
every five or six years.
1t long has been known that the
cells, the bricks of which the body
is built, constantly are degenerat-
ing and being replaced by new ones
made up of entirely new chemical
molecules. This means that very
little of the child, if anything, is
left in the adolescent or the adult.
There are new hands, new heart
and a new brain, but the process
has been so gradual that it seems
like the same individual.
This rebuilding process may be
much faster than has hitherto been
supposed and involve every bit of
the body substance. according to
observations reported to the Ameri-
can Physiological Society here today
by Drs. Adolph Schoenheimer,
Michael Heidelberger, D. Ritten-
berg and S. Rather OF Columbia
University.
1t has been known that the fats
change very rapidly, but physiolo-
gists have supposed that the pro-
teins. nitrogen-containing molecules
which make up nerve. brain, muscle
and many of the body chemicals,
were quite stable. Certain elements
of the food are changed by the proc
esses of digestion into proteins
known as amino acids which go to
make up the more complex proteins
of the organs.
Tags" Prove Requirements.
The Columbia biochemists made
up these amino acids in the
laboratory with tagged elements
atoms either heavier or lighter than
normal particles Of the same ele-
ment or else with the property OF
radioactivity-and fed them to
animals. They had already in
iected the rabbits and rats with
which they experimental with
pneumonia antibodies, which are
largely protein in makeup.
They found that the chemical
composition of these antibodleS
which could be isolated from the
blood changed rapidly and that the
tagged atoms soon could be found
in them. This proved that the body
proteins continuously are being re-
placed with new molecules.
Allowing for the protein lag, ply
siologists in the past have believed
that one was probably a completely
new individual once every seven
wears. The new evidence indicates
that the transformation Is much
more rapid, although its pace cam
not be exactly measured and may
change from individual to indl-
vidual.
1t was also reported that the body
of a man contains a lot more free
water than that of a woman, mdi-
eating that the female, cell for CELL
is a more complex and more solid
organism.
Salt Test Used.
Drs. Bernard B. Brodie, Max N,
Friedman and Louis r. Farraro OF
Fordham University, New York, in
jected both male and female adults
with sodium bromide, salt which
dissolves readily in the water OF the
body. Samples of this water pro-
vided the basis for an estimate OF
the total amount Of water In a
person.
Water in the body Is Of two kinds,
that between the cells, and that in
side them. The former was the
only kind that could be measured
by the experiment. 1t was found
that men had about 10 per cent
excess over women. 1t also was
higher in normal or active males
than in hospital patients who were
confined to bed.
There is no way Of measuring
the water inside the cells and
women may have more Of 1t than
men.
At the same meeting was re-
ported q queer and inexplicable
wrinkle in brain evolution when
Drs. Carl r. Schmidt and P. r.
Dumke, pharmacologists of the
University of Pennsylvania, told OF
measuring the flow of blood through
the brains of monkeys.
Lower Than in Dogs.
1t had previously been ascer-
tanned that the brain of a dog re-
ceives an amount of blood equal
to its own weight every minute.
In the monkey there is relatively
half this amount. The technique
is so delicate that it is impossible
to apply it to a man but the prob
ability is that the blood flow through
the human brain is even slower.
The experiment was performed,
DR.. Dumke reported. by injecting
with a small syringe tiny bubbles
of air into an exposed artery lead
ing into the brain of an anesthetized
living monkey. BY timing the speed
with which the bubbles moved along
the artery, the rate of blood flow
was obtained.
The effect of various drugs on
the rate of flow also was studied.
It was found that injections of
adrenalin caused q decrease in rate
while caffeine produced a slight in