Evening star., 1937-05-18
STARS, MEN AND ATOMS
Notebook of Science Progress in Field.
Laboratory and Study.
BY THOMAS r. HENRY,
What makes the heart beat?

What makes the heart beat7
This unwilled behavior which con-
tinues in almost undertaking rhythm as
long as the individual remains alive Is
apparently the result of a balance be-
tween two hitherto unknown chemical
substances secreted by the two sets of
nerves leading to the organ OF life.
The heart Is controlled by the auto
nomic nervous system which is divided
into two parts with antagonistic func-
tions-the sympathetic and the para
sympathetic. Both send nerve fibers to
the heart.
From the sympathetic nbers when they
are stimulated Is secreted . minute
amount Of 4 substance very similar to
adrenalin in its action, but not chem
ically identical with this product of the
adrenal glands Like adrenalin in the
blood stream, this substance speeds the
heart From the parasympathetic fibers
is secreted . substance known as acetyl
choline-a compound Of acetic acid and
choline which is found abundantly in
almost all body tissue. 1t slows the heart.
Then the adrenAlin-like substance is shot
into 1t from the sympathetic fibers and
speeds 1t up again. The balance be-
tween these two is the heart beat.
This is essentially the explanation
offered by Sir Henry Dale, 1895 Nobel
prize winner and director Of the National
Institute Of Medical Research in Lon
don, who will deliver public lecture
before the newly organized Washington
Academy of Medicine at the Medical So
ciety auditorium tonight This, 1t is ex-
vH1A hN, NJ iS
. radically new concept OF nerve action
which Is essentially due to Sir Henry
Dale's researches.
He has been the first to recognize the
true nature Of the parasympathetic Sc
cretion-or hormone. The acetyl cho-
line Is = very unstable combination. AL
most the instant 1t Is released from the
nerve fibers it breaks up into Its con-
stituent parts which have no known
physiological action. The same is prob
ably true Of the adrenalin-like stimulant
Thus neither OF these powerful chem
icals can exert its effect more than q
fraction Of q second. The acetyl choline
1t has been found, mimics all the effects
Of parasympathetic nerve action and has
been used In medicine as powerful
lowerer Of blood pressure.
Assuming that similar substances are
secreted by the central nervous system
flbers, according to DR.. Carl Voegtlin,
professor OF pharmacology at the Ma
tional Institute Of Health, the discovery
Of these hormones also offers an ex-
PLANTATION for the passage of nerve i'm
pulses across synapses, or intervals be-
tween the flbers Of different nerves. It
is not like an electric spark jumping a
gap nor like an electric current curried
through liquid between the ends of two
wires. The new picture is that one nerve
fiber in action secretes some of one chem
ical or another which comes into con-
tact with the fiber Of another nerve and
starts up similar action.
The beginning Of the work, 1t IS
pointed out, may be considered as dating
back more than q quarter Of q century
when DR.. Reid Hunt, DR.. Voegtlin's pre-
decessor ut the Public Health Service
here, speculated on the role Of choline.
It received an enormous impetus In
Austria Just after the war when it was
found that the liquid perfusion from one