Iowa state bystander. [volume] (Des Moines, Iowa) 1894-1916, 1915-01-29
HoRMoNE S.

word "hormones" Is intended to desig
nate a series of chemical bodies man
ufactured within the cells of one or
gan and entering the circulation to
excite or stimulate distant organs into
activity.
1t has generally been supposed that
the digestive functions were carried
J on solely under reflex nerve control.
But Edkins in 1906 carried out Sc
ries of experiments to determine
whether a chemical mechanism may
not also account for the secretion OF
gastric juice. which is excited by the
introduction Of substances into the
stomach In a series of carefully con-
! trolled observations it was proved that
Il; the mere introduction of a neutral So
/ lgtion into the stomach caused no Sc
! cEsIio2 of gastric juice and that there
waS 10 absorption OF the solution. the
Eui6 removed az the end OF an hour
! having the same bulk and the same
) neutral reaction as the solution orig
iEsly introduced.
! The Injection of peptone. of acid, OF
/ broth. Or OF de1trin into the blood
stream produced no secretion of gas
tric Juice, but If in the course of the
hour during which the fluid was al
lowed TO remain in the stomach So
luton made by boiling mucous men,
bEane from the pyloric end of stom-
nrrl r-T- aoSEa vi
pepsone. 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utes, then the fluid withdrawn from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
vas found to be distinctly acid and to
+ have protein digestive powers-that
is to say, it now contained hydro
chIoric 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
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 a "hormone."
\ This substance is produced in that
portion Of the stomach where the pro-
cess of absorption is most pronounced,
and it stimulates into activity that
portion OF the stomach which is under
direct nerve control.
Normal gastric secretion appears to
be due to two cooperating factors.
The hrst and most important is the
secretion arising from nerve impulses
produced through the pneumogastric
nerTe and originating in the idea Of
food in ths higher parts Of the brain.
FROM the eight OF food and by the
stimulating of the MUCOUS membranes
81 the mouth. The second factor pro-
rides for the continued secretion of
gastric Juice long after the mental
effects have disappeared. This il
chemical and depends or the produc.
ton in the cells at the pyloric end of
the stomach of specific stimuIant or
hormone. which being absorbed into
the blood is carried to all parts Of the
body, where it acts by exciting all the
various glands concerned in the d.
gestiye act.
The researches of Pawlow and 9TH
ers seem to indicate that the quantity
and the properties of the secretions
vary with the character of the food
eaten. 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 general circula-
tion.. ,,f& .v
Another significant hint Of this &C.
ton is furnished by the experiments
Of Startling and Lane-C Clayton 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
oyaries, placental and uterine tissues
had no such effect; hence, they con.
Eclude that q specific chemical sub,
stance, hormone, Is produced in the
fetus itself which being absorbed into
the maternal blood acts upon the
mammary gland. stimulating It to
growth. IS i. .sSl t5. NJ: +.
There Is indisputable evidence Of
the existence of similar bodies which
determine the secretory activity both:
Of the liver as well as Of the intes.
final glands. Obviously these sub
stances must be derived from the gen.
eral food supply. and, therefore, 1t is
easy TO grasp the significance of
Funk's statement that the vitamines.
those complex heterogeneous molecules
contained "A the germ and the bran.
coats Of seeds ana grains, are the
s \ ' ths y substancs of ths hormones.