during digestion he has found an acid reaction in the contents of the
intestine beyond the opening of the bile-duct, with no precipitation of
the albumen (_op. cit._, p. 82).]
{622} As far as we now know, the function of the bile is to neutralize
the acidity of the duodenal contents, and thus pave the way for the
action of a digesting fluid of much greater potency and of much higher
function.[4]
[Footnote 4: In order still further to demonstrate the necessity of
bile-action as a preparation for pancreatic digestion, it may be
mentioned that in artificial experiments, with a heat equal to that of
the body, if antiseptics analogous to gastric juice and bile are not
used, there is a too rapid change from alkalinity to acidity, and
consequently all of the starch is not converted into sugar before it
develops lactic acid with putrefactive disorganization. A deficiency of
bile, therefore, is a cause of intestinal indigestion (Bartlett, _op.
cit._, pp. 12, 13).]
This fluid, the pancreatic juice, is composed of inorganic salts,
albuminoids, and certain specific ferments, and has an alkaline
reaction. It has a threefold operation upon the softened mass with
which it now comes in contact: 1. The starch of vegetable matter, which
has been only slightly acted on up to this time, is now rapidly
converted into grape-sugar by a peculiar diastatic ferment more active
than any other known ferment. 2. Albuminous matters (proteids) which
have escaped digestion in the stomach are changed into a soluble and
absorbable pancreas--peptone. Trypsin is the active ferment in this
case (Kühne), and it is only in alkaline or neutral solutions that the
albuminoids are readily dissolved. The necessity of neutralization by
the alkaline bile is thus demonstrated. 3. A ferment distinct from the
others splits the fats into fatty acids and glycerin, and emulsifies
them so that they can be taken up by the lacteals lower down.
Experiments made by mixing albuminates with pancreatic gland-extract,
under favorable conditions, show after a certain time the presence of
leucin, tyrosin, hypoxanthin, and asparaginic acid. In a feebly
alkaline or neutral solution a faint putrefactive odor is soon noticed,
with the development of bacteria; ammonia, sulphuretted hydrogen,
hydrogen, and carbonic acid--evidences of the putrefaction of
albumen--are also detected.
It is difficult to tell when normal digestion in the intestines ends
and putrefaction begins. The conclusion is, that the normal action of
pancreatic juice (trypsin) gives origin to bodies met with in the
ordinary putrefaction of albumen.[5] This thin border-line between
normal intestinal digestion and the decomposition of the intestinal
contents has an important bearing on the facts of intestinal
indigestion.
[Footnote 5: Ewald, _op. cit._, p. 92.]
The intestinal juice performs a minor but independent part in
digestion. It converts albuminous matter into peptone, and hydrated
starch into sugar. Its function is therefore supplementary to that of
the gastric and pancreatic secretions.[6]
[Footnote 6: Ewald, _op. cit._, p. 103; also, "The Functions of the
Intestinal Juice," Charles L. Dana, _Med. News_, Philada., July 15,
1882, p. 59.]
When food enters the mouth the process of digestion begins, and all the
activities of the glands concerned in digestion are probably at once
set in motion. Mastication excites, by reflex action, pancreatic
secretion; the acid chyme touches the orifice of the common bile-duct
and stimulates the outflow of bile; the neutralized chyme next invites
pancreatic digestion. For the integrity of intestinal digestion it is
required that mastication and stomach digestion should be normally
performed.
The intestinal movements which are so necessary to digestion by making
successive changes in the position of the intestinal contents are {623}
controlled by nervous arrangements, but may occur independently of the
central nervous system. The ganglia of Auerbach and of Meissner in the
intestinal wall are sufficient for the development of peristaltic
waves. The irritation of the mucous membrane by food, hyperæmia, and
the pouring out of digestive juices, and intestinal movements, are
parts of one process. Paralysis by section of the splanchnic leads to
hyperæmia of the intestinal vessels and increased peristalsis;
stimulation of the splanchnic causes anæmia of the intestinal wall and
arrest of movement. Local cold by producing anæmia brings about the
same result.
The products of digestion as they pass toward the jejunum consist of
diffusible peptones, sugar, emulsified fats and oils, and substances
which have escaped digestion, as fragments of muscular fibre,
starch-corpuscles, connective tissue, hairs, or other foreign matters.
The bowel contains also carbonic acid, hydrogen, nitrogen, sulphuretted
hydrogen, and marsh gas. The mass, alkaline or neutral in the duodenum
and jejunum, becomes acid in the ileum from the putrefaction of albumen
and fermentation. The peptones and sugar pass by osmosis into the
blood-vessels of the portal system and thence to the liver. In the
liver the sugar is converted into glycogen (carbohydrate), and stored
in the liver-cells until needed for the maintenance of animal heat and
for the nutrition of the tissues. The peptones are used in part to
supply the nitrogenous waste of tissue, but much of the albuminoid
matter is broken up in the liver into glycogen and urea, the latter of
which is excreted by the kidneys as waste matter.
The minute granules of oil in emulsion are taken up by the epithelial
cells covering the villi; thence they enter the adenoid tissue of the
villi on their way to the lymphatic radicles, the lacteals. From here
the passage is open to the underlying lymphatic vessels and to the
larger abdominal lymph-vessels and the thoracic duct beyond.
Intestinal digestion is not completed and the body does not receive its
pabulum until the products of digestion have reached the liver and the
thoracic duct.
ETIOLOGY.--It is usually said that intestinal dyspepsia is more common
in women than in men, but the contrary is the rule. Some of its most
common causes--over-eating and the eating of indigestible food--are
especially vices of men.
It is more frequent between the ages of forty and fifty, but no age is
exempt. Infants at the breast, children of any age, adults, and old men
and women are alike subject to it. Men in middle life begin to suffer
from the imprudence and carelessness of youth and from the anxiety and
cares of business. The indulged children of rich parents and improperly
bottle-fed infants frequently suffer.
Heredity and idiosyncrasy have a certain influence in determining the
prevalence of intestinal dyspepsia. The distaste for and inability to
digest vegetables, fruits, and fats are often peculiarities of family
history. The occurrence of cases in the same family is often explained
by improper food, bad cooking, and irregular hours, to the evil
influences of which all the members are similarly subjected.
All conditions of the organism which result in a depraved or altered
blood-supply, as anæmia, primary and secondary rachitis, chronic
syphilis, and continued febrile diseases, are causes of intestinal
indigestion. {624} The connection of the indigestion of fats with the
strumous diathesis and with phthisis is undisputed. J. Hughes Bennett
traced the origin of phthisis to defective fat-digestion; strumous
indigestion and the indigestion of fat are synonymous terms.
Debilitating influences, such as bad air, want of cleanliness and
outdoor exercise, impair functional activity in the intestines as
elsewhere. Sexual excesses, but especially masturbation, have a special
influence for evil in this direction.
The influence of the mind upon the digestion of starch and fats is even
greater than upon gastric digestion, for no other reason perhaps than
that the former is a more complex function and less easily relieved
than the latter. Prolonged or excessive mental labor does not do so
much harm as mental worry, over-anxiety, and the strain and overwork of
business. Professional men--lawyers, physicians, and clergymen--who
become over-burdened with responsibilities, and who sympathize too much
with the distresses of others, are very prone to suffer. The careworn
face with lines about the mouth and forehead is one of the plainest
signs of duodenal defect. The proper secretion of the juices of the
intestine and normal peristalsis are impossible where brain and nerves
get no rest. The too rapid mental development of the children of the
present day is a fruitful source of weakened fat-and-starch digestion
and of impaired development. So long as children are sent to the public
school at four and six years of age, there will continue to grow up a
precocious race with active brains in feeble bodies.[7] This injurious
result is largely brought about by the direct interference of premature
brain-development with the complex intestinal processes of digestion
and absorption.
[Footnote 7: In eight of the States and Territories the minimum age for
entering the public school is fixed at four years; in seventeen States
at five years; in the others, except two, at six years. The two notable
exceptions are Alabama and New Mexico, where children do not enter
school until the age of seven.]
Wealth, with ease and inactivity, and sedentary occupations, contribute
to the same end by lessening the need of food, and thus debilitating
the organs of digestion by inaction. Sedentary pursuits, especially
those in which the body is bent forward and constricted or compressed
at the waist, interfere with active function in the intestine. This is
the case in tailors, shoemakers, etc. Tight-lacing in women and a too
tight trouser-band in men are injurious.
Hot climates, especially when combined with dampness, lead to disorder
in the intestine and liver. This effect is most marked among persons
coming from colder climates, as among the English in India, who keep up
the habits of eating to which they have been accustomed at home. The
lessened demand destroys the appetite, and stimulants and condiments
are resorted to to whip up the inactive functions. The intestine is
loaded with a mass of crude, unaltered matter which can with difficulty
be disposed of. Chronic indigestion results, varied with acute attacks
of diarrhoea or dysentery. The portal system is filled with an excess
of albuminoid material which the liver is unable to store away. The
excess is got rid of by conversion into uric acid. Lithæmia and chronic
congestion and enlargement of the overloaded liver result, with their
many attendant evils.
Over-eating occasions first gastric and then intestinal indigestion by
the {625} entrance of unaltered food into the duodenum. Eating without
hunger often involves the taking of food which the body does not need
and which the stomach cannot digest. Diners-out rarely go through a
season without one or more internal revolts. A too-varied diet, a
dinner of many dishes, is faulty in variety as well as in excess. On
the other hand, a too great sameness in diet and the prolonged use of
one or two articles of food which are not easy of digestion, and which
have a great deal of waste, fatigue and then disorder intestinal
digestion. This is a fault into which children are often allowed to
fall.
Indigestible food and an excess of starchy or fatty food conduce to
disorder of duodenal digestion. In conditions of debility and anæmia
and in the convalescence of fevers the deficiency of saliva involves an
inability to digest starch in the mouth and points to a corresponding
want in the duodenal secretions. The improper use of alcoholic liquors,
taking them on an empty stomach between meals and in excess, tends to
direct irritation of the mucous tract. Condiments in large quantity
have the same effect.
Irregularity in the hours of eating and a faulty distribution of the
amount of food disturb the perfect working of the mechanism of
digestion. Very light breakfasts and very late and large dinners are
injurious. The habit, now quite general in cities, of deferring the
breakfast proper until midday, leaves the system too long--fifteen to
sixteen hours--without proper food and weakens digestive activity.
Intestinal indigestion is very common among Americans who have lived
abroad and adopted European customs.
Another cause which is unfortunately very common is the imperfect
mastication and insalivation of food, due to too great haste in eating,
to defects in the teeth or gums, or to a deficiency of saliva. The
saliva no doubt sometimes possesses a feeble diastatic power, although
abundant in amount. Carnivorous animals bolt their food, but
vegetable-eaters must masticate. Slow mastication transforms starch
into sugar, and at the same time excites secretive activity in the
glands of the digestive tract, especially in the pancreas. The more
thoroughly this preliminary function is performed the better
preparation is there for the subsequent acts of digestion.[8]
[Footnote 8: "The familiar act of chewing is seldom a subject of
reflection, yet it throws into motion a more complicated system of
levers, accompanied by a drain of fluids from more curiously adapted
apparatus, than the arts can parallel" (Leared, _On Indigestion_,
London, 1863, p. 3).]
The chewing of tobacco, a wretched habit which is much less common now
than formerly, and to a less extent the habit of smoking, are causes of
deficient, altered, or depraved saliva, and secondarily of altered
pancreatic secretion. The thin smoker grows fat when he abandons the
weed.
The normal functions of the intestines are interfered with and
indigestion is set up by constipation. Every one has felt the activity
in digestion which accompanies the regular habit of defecation, and the
torpor and oppression which depend upon an unemptied colon. "There is a
concert of action in virtue of which the whole muscular apparatus of
the digestive tube sympathizes with that of the large intestine. This
concert of action, which induces pathological states, is the reason why
in the {626} physiological state a regular contraction of the whole
intestinal tube, including the stomach, is the consequence of the
regular contraction of the large intestine."[9]
[Footnote 9: Trousseau, "Les Dyspepsies," _L'Union médicale_, tome xi.,
1857, p. 313.]
An excess of acid in the stomach would enfeeble the solvent power of
the intestinal fluids by antagonizing neutralization by the alkaline
bile; the same effect follows any cause which prevents the outflow of
the bile, as the plugging of the common bile-duct by mucus and
epithelium in catarrh or by an impacted gall-stone. The emulsification
of fats is incomplete and decomposition in the intestine follows. The
antagonism of the saliva and the gastric juice, of the gastric juice
(or the chyme) and the bile, must preserve their delicate and nice
adjustment in order for digestion to be properly performed.
Diseases of the pancreas seriously embarrass digestion in the
intestine. Lesions of this organ, as catarrh of the duct, cancer, fatty
degeneration, etc., may result in impaired emulsification of fats,
fatty diarrhoea, and wasting.
Intestinal indigestion accompanies hyperæmia and catarrh of the
intestinal mucous membrane, diseases of the heart, lungs, and liver,
and all other causes which impede portal circulation.
SYMPTOMS.--Intestinal indigestion cannot be so clearly pictured as that
of gastric dyspepsia. This is owing to the frequent concurrence of the
two conditions, the gastric symptoms taking precedence of the others.
The more complex nature of the intestinal function is another reason,
intestinal indigestion having more modifications in its phenomena. In
the stomach there is only one active secretion; in the intestine there
are three, all participants in the act of solution. An alteration in
the quality or quantity of one of these--the bile, for example--would
lead to different symptomatic results than would follow another
defective secretion, as that of the pancreas, for instance. Clinical
study has not yet fully differentiated the forms of indigestion due to
these several deficiencies. But there are certain well-defined symptoms
associated with intestinal disorders which are distinguished by their
seat, time of their appearance, and their character from analogous
symptoms connected with the stomach.
Intestinal indigestion may be acute or chronic. The latter is the more
typical and more common form.
When a sudden attack of indigestion in the intestine results from the
entrance into the duodenum of food in such a state that it cannot be
digested, the result is the rapid development of pain, flatulence,
borborygmi, and frequently of fever, ending in diarrhoea, with the
escape perhaps of the offending matter: a condition then exists which
may be called acute or subacute intestinal catarrh or acute intestinal
indigestion. One name would be as correct as the other. Slight acute
forms are marked by a coated tongue, loss of appetite, headache, pains
in the limbs, distress in the epigastrium or right hypochondrium,
flatulence, and constipation. These might be accompanied by symptoms
indicating a disorder of the liver functions--light-colored stools,
slight jaundice, lithates in the urine. But intestinal indigestion
alone can cause these symptoms without the condition of so-called
biliousness being present. The local symptoms are due to the presence
in the intestine of an {627} imperfectly-altered mass and the
development of gas; some of the general symptoms are reflex; others, as
headache and lassitude and pain in the limbs, come from the absorption
into the blood of the gases, particularly sulphuretted hydrogen. The
participation of the stomach in acute attacks of this sort modifies the
symptoms as here described. Such attacks are apt to recur at intervals.
If the causes which bring about acute disorder in the intestine are
allowed to continue, the intervals between the acute or subacute
attacks diminish, and there is in time a fixed state of chronic
intestinal dyspepsia in which the partly-altered food coming from the
stomach is not properly prepared for absorption. Instead of digestion
there is decomposition; the transition is easy from the one to the
other of these states. The symptoms connected in this case with the
digestive organs are pain, occurring from two to six hours after
eating, in the right hypochondrium, the epigastrium, or the umbilical
region, due to distension of the intestine with gas. This pain is dull,
not always fixed, lasts from one to three hours, and is accompanied by
tenderness on pressure over its seat.
Tympanites, borborygmi, and a sensation of fulness in the abdomen
accompany the pain or may exist without it. Gaseous accumulations in
the intestine, the cause of these symptoms, have an independent source,
being produced by decomposition in the gut itself, and are not due to
the descent of gases from the stomach through the pylorus. What is a
physiological and temporary condition becomes in disease a distressing
symptom of long duration. In intestinal indigestion the gut is nearly
always inflated with gas, which in its movement produces rumbling
noises. In acute indigestion it is rapidly formed in large amount, and
by the stretching of the wall of the bowel and pressure on
nerve-filaments causes intense pain--colic. In the chronic form the
distension excites uneasy sensations, prevents sleep, and may be so
great as to cause dyspnoea by pushing the diaphragm upward. When the
small intestine is distended the greatest swelling may be about the
umbilicus, or the abdomen may be evenly rounded. When the colon is
chiefly or solely inflated, its outline across the upper part or at the
sides of the abdomen can be easily made out.
Constipation is a common feature. It is produced by a loss of
contractility of the intestinal wall. The more direct causes are
over-distension of the gut and disturbance in the circulation and
innervation of its walls. The stools are hard and dry, and are expelled
with difficulty. Sometimes they are coated with shreds or films of
mucus, the product of a chronic catarrh of the mucous membrane of the
colon, or mucus from the small intestine is intimately mixed with the
mass. Diarrhoea may alternate with constipation. The passage of
unaltered food, as fragments of meat, vegetables, or fruit, clearly
shows the extent to which indigestion exists. By the microscope
particles of food which have escaped complete disintegration may be
detected. The stools vary in color. Very dark-green or black discharges
show an excess of bile; light-yellow or gray slate-colored, a
deficiency. Stools of the latter character are highly offensive in
odor.
Hemorrhoids are often present, being due to the sluggish portal
circulation and to the pressure of hard fecal masses in the rectum. The
appetite is not impaired, as a rule, but it may be fitful or irregular.
A bad {628} taste in the mouth, and a swollen, relaxed, and coated
tongue may exist without any decided gastric disease.
The symptoms of disorder of the nervous system are more marked than in
gastric dyspepsia. This results not so much from the depressing
influences of pain as from the peculiar malnutrition of the
nerve-tissue. In order to have furnished to the blood the pabulum out
of which the nerve-elements are reconstructed the digestion of fat must
be normally performed. Lecithin, which is found conspicuously in the
brain and nerves, is a complex fat containing phosphorus and
nitrogen.[10] Anæmia and waste follow directly from interference with
the digestion and absorption of fats and starch in the intestine, but
the most delicate, the most easily-disorganized solid of the body, the
nerve-tissue, is the first to feel and to manifest its want of natural
supply. And so the dyspeptic whose intestine is at fault becomes
depressed in spirits, hypochondriacal, absorbed in the contemplation of
his sufferings, analyzing them and referring them to the most serious
organic changes. There are sleeplessness, disturbing dreams, the habit
of waking at a fixed hour, dizziness, uneasy sensations or pain in the
head, and disturbances of the special senses, as buzzing in the ears,
muscæ volitantes, and attacks of blindness. Headache assumes often the
form of hemicrania; it may be in the forehead or about the eyes.
Attacks of vertigo and sensations as if the ground were rising beneath
the feet accompany intestinal flatulence. Confusion of thought, loss of
the power of application, and mental inertia are frequent sources of
anxiety. Paralysis has been noted as following indigestion.
Epileptiform convulsions and milder epileptic attacks can be traced to
undigested matter in the intestine.[11] Various modifications of
general sensibility also happen: there are pains in the back and limbs,
hyperæsthesia, and anæsthesia. An inaptitude for exertion, especially
for mental labor, forces the boy to give up school and college life.
Successful careers are abandoned by men who at the cost of neglecting
all the rules of health have succeeded for a brief period in passing
their fellows in the race. Sudden attacks of fainting have been noted,
with very grave collapse. These are the effect upon the nervous centres
of the absorption of sulphuretted hydrogen which has been evolved in
large quantities in the intestine.[12] The daily occurrence of
vertiginous and other morbid sensations, with melancholia, may be due
to the daily toxic absorption of gas from the intestine.
[Footnote 10: Fothergill, _Indigestion and Biliousness_, New York,
1881, p. 76.]
[Footnote 11: Chambers, _The Indigestions_, London, 1867, pp. 305-307.]