Evening star., 1942-03-03
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Laboratory. Field
And Study
BIZ Thomas r. Henrp.

By Thomas r. Henry.
Soon prospective recruits may be
"ducked" for the Navy.
This proposal Is advanced by three
naval medical officers headed by 1t.
Comdr. A. R. Behnke, authority on deep
sea diving, in o report to the American
Medical Association.
It Is inspired in part by their finding
that. under present regulations, II out
Of 25 professional football players would
be unable to pass the physical examina-
| tions because Of being overweight
although they obviously are in fine
physical condition.
At present. they point out, the criterion
OF examining officers is the ratio Of
height to weight.
They propose, instead, that the cri-
terion be an individuals specific gravity,
| the ratio of his weight to the amount
| Of water displaced. This Is the old
principle Of the Greek philosopher, Ar
chemedes. It requires that, after weigh
| ing on an ordinary scales. the subject
zoe suspended below the suface Of water
on q line leading up to . spring scale
graduated in ounces. A weighted lead
belt maintains negative bouyancy for
all types Of persons"
The weight in water then is subtracted
from the weight In air. The result,
after making allowances for residual air
in the system. is the specific gravity Of
the individual.
What the Navy seeks to avoid. 1t is
pointed out in the report, is not over
weight, but "overfat." The extra pounds,
as in the case of the football players.
may be due to sound, hard muscle.
Fat. it appears from their experiments,
has quite low specific gravity. Hence
the higher the figure for an individual
the better, since it means solidity.
The first subjects were 90 healthy
sailors between 20 and 40 years Of age.
DR.. Behnke, together with Its. B. G..
Feen and w. c. Welham, found that the
highest specific gravity-1.0Sl times the
weight Of water per unit volume-was
obtained with men weighing on an aver
age about 148 pounds. The lowest was
1056 the weight Of water for men who
averaged 176 pounds. There were, how
ever, striking individual differences. 1t
looked as If the lower the specific gravity
the greater the amount Of useless fat.
They then turned to the professional
football players. They chose Is Of the
| foremost athletes in the United States,
nearly all of whom have been all-Amer-
leans. They were playing strenuous
games at least once week. Regardless
Of rules, 1t. Behnke and his colleagues
believed it would be absurd to believe
that the majority of these men were
physically unfit for the hardships of
naval service.
They weighed an average of 200 pounds
each. But when they were suspended
in water and the difference calculated
| it was found that the average specific
| gravity was 1080 times the weight Of a
| similar volume of water. Except for
their great muscular strength they prob
ably would make poor swimmers. The
| gravity figure, almost equal to the high
| est obtained among the naval personnel,
| showed that their bodies were made up
| of material relatively heavy compared
with the weight of water. Fat is hardly
any heavier.
"On the basis of the standard height
weight tables used by insurance COM
panies and In the military service" they
say in their report to the American
| Medical Association, at Of these Is ath-
| letes would be considered as not physi-
| cally qualified for military duty or first
class insurance risk.
But of the II rejected allAmerican
football players, II fall into the group
possessing high corporeal specific gravity.
| According to our classification these II
men are in prime physical condition, If
| absence Of excessive fat is criterion Of
fitness. The type of physical exertion
that these men are called upon to make
is proof of their sturdy physique. esti-
mated in terms Of speed, agility and en-
durance.
I'VE propose, therefore, the classiica-
ton of men as overweight on the basis
Of specific gravity of the body mass,
using a tentative dividing line Of 1060
| (the weight Of water) for the elimina-
ton Of the obese"
They stress that their conclusions are
not to be considered as those OF the
Navy Medical Corps. and that they are
speaking purely as private individuals.
British experimenters have arrived, by
means of experiments with goats, at the
| first clear ideas Of the effects of blast
| shock.
Throughout the bombardment Of Eng
lish cities there were curious paradoxes.
Persons comparatively near bomb ex-
| plosion would be unhurt, while others,
further away, would be found dead with
. out any visible sign of injury.
There were two possible theories, 1t was
decided. Either the blast acted like a
heavy blow on the chest or the shock
wave, which had travelled through the
nose and mouth, lacerated the bronchial