Crossville chronicle. [volume] (Crossville, Tenn.) 1894-current, 1915-02-24
HORM MON ES.

Taken from the Greek language
and meaning to arouse or excite. the
word "hormones'' is intended to desi&
nate a series of chemical bodies man
ufactured within the cells of one or
gan and entering the circulation 10
excite or stimulate distant organs into
activity.
1t has generally been supposed that
the digestive functions were carried
on solely under reflex nerve control.
But Edkins in 1906 carried out SO
ries of experiments to determine
whether a chemical mechanism may
not also account for the secretion or
gastric Juice. which is excited by the
introduction of substances into the
stomach. In a series of carefully con-
trolled observations 1t was proved that
the mere introduction of neutral So
luton into the stomach caused no Sc
cretion of gastric juice and that there
was no absorption of the solution, the
fluid removed at the end of an hour
having the same bulk and the same
neutral reaction as the solution orig
inally introduced.
The injection of peptone, of acid, OF
broth, or of deXtrin into the blood
stream produced no secretion of gas
trio juice, but if in the course of the
hour during which the fluid was al
lowed to remain in the stomach ST.
luton made by boiling mucous mem
brane from the pyloric end of stom-
ach with water, or with acid, or with
peptone, was injected into the blood
stream at intervals of about ten min
utes, then the fluid withdrawn from
the stomach at the end of the hour
was found to be distinctly acid and to
have protein digestive powers-that
Is to say, it now contained hydro
chloric acid and pepsin.
Similar solutions made from the car
diac end of the stomach will not pro-
duce any secretion of acid and pepsin.
and this is held to prove that the
pyloric end Of the stomach produces a
substance which is absorbed into the
blood stream and carried to all the
glands of the stomach, where it acts
as a specific excitant of their secre-
tory activity. This substance has been
called the gastric "secretin"-it is
what Startling named "hormone.
Normal gastric secretion appears to
be due to two cooperating factors
The first and most important is the
secretion arising from nerve impulses
produced through the pneumogastric
nerve and originating in the idea Of
food in the higher parts of the brain.
from the sight of food and by the
stimulating Of the mucous membranes
of the mouth The second factor pro-
vides for the continued secretion Of
gastric juice long after the mental
effects have disappeared. This Is
chemical and depends on the produc-
ton in the cells at the pyloric end Of
the stomach of specific stimulant or
hormone, which being absorbed into
the blood is carried to all parts of the
body, where it excites the glands con.
cerned in the digestive act.
The researches of Pawlow and 9th
ers seem to indicate that the quantity
and the properties of the secretions
va'v with the character of the food
eate". The quantity of the secretion
varies also, other conditions being the
same, with the amount of food to be
digested.
On a given diet the secretion as
sumes certain characteristics and
Pawlow is convinced that further
work will disclose that the secretion
of the stomach is not caused normally
by general stimuli affecting it all alike
but by specific stimuli contained eth
er in the food or produced during d.
gestion from the food contents the
action of which is Of such kind as
to arouse reflexly the secretion best
adapted to the particular food in
gested. Undoubtedly this is due to
the hormones in the circulation.
Another significant hint of this &C.
ton is furnished by the experiments
of Startling and Lane-Claypon on the
mammary glands. These investiga-
tors found that the extracts made
from the body of the fetus when in
jected repeatedly into the blood
stream Of a virgin rabbit caused
genuine development of the mammary
glands, closely Stimulating the growth
that normally occurs during preg-
nancy. Similar extracts made from
ovaries, placental and uterine tissues
had no such effect; hence, they con-
clude that specific chemical sub
stance, a hormone, is produced in the
fetus itself which being absorbed into
the maternal blood acts upon the
mammary gland, stimulating 1t to
growth.
There is indisputable evidence OF
the existence of similar bodies which
determine the secretory activity both
of the liver as well as Of the tntes
final glands. -. - ~,