THE FECES
As commonly practised, an examination of the feces is limited to a
search for intestinal parasites or their ova. Much of value can,
however, be learned from other simple examinations, particularly a
careful inspection. Anything approaching a complete analysis is, on
the other hand, a waste of time for the clinician.
The normal stool is a mixture of--(_a_) Water; (_b_) undigested and
indigestible remnants of food, as starch-granules, particles of meat,
plant-cells and fibers, etc.; (_c_) digested foods, carried out before
absorption could take place; (_d_) products of the digestive tract, as
altered bile-pigments, mucus, etc.; (_e_) products of decomposition,
as indol, skatol, fatty acids, and various gases; (_f_) epithelial
cells shed from the wall of the intestinal canal; (_g_) harmless
bacteria, which are always present in enormous numbers.
Pathologically, we may find abnormal amounts of normal constituents,
blood, pathogenic bacteria, animal parasites and their ova, and
biliary and intestinal concretions.
The stool to be examined should be passed into a clean vessel, without
admixture of urine. The offensive odor can be partially overcome with
turpentine or 5 per cent. phenol. When search for _Amoeba coli_ is to
be made, the vessel must be warm, and the stool kept warm until
examined; naturally, no disinfectant can be used.
{236} I. MACROSCOPIC EXAMINATION
1. Quantity.--The amount varies greatly with diet and other factors.
The average is about 100 to 150 gm. in twenty-four hours.
2. Frequency.--One or two stools in twenty-four hours may be
considered normal, yet one in three or four days is not uncommon with
healthy persons. The individual habit should be considered in every
case.
3. Form and Consistence.--Soft, mushy, or liquid stools follow
cathartics and accompany diarrhea. Copious, purely serous discharges
without fecal matter are significant of Asiatic cholera, although
sometimes observed in other conditions. Hard stools accompany
constipation. Rounded scybalous masses are common in habitual
constipation, and indicate atony of the muscular coat of the
intestine. Flattened, ribbon-like stools result from some obstruction
in the rectum, generally a tumor or stricture from a healed ulcer,
most commonly syphilitic. When bleeding piles are absent,
blood-streaks upon such a stool point to carcinoma.
4. Color.--The normal light or dark-brown color is due chiefly to
altered bile-pigments. The stools of infants are yellow, owing partly
to their milk diet and partly to the presence of unchanged bilirubin.
Diet and drugs cause marked changes: milk, a light yellow color; cocoa
and chocolate, dark gray; various fruits, reddish or black; iron and
bismuth, dark brown or black; hematoxylin, red; etc.
Pathologically, the color is important. A golden yellow is generally
due to unchanged bilirubin. Green stools are not uncommon, especially
in diarrheas of childhood. The color is due to biliverdin, or,
sometimes, to {237} chromogenic bacteria. Putty-colored or "acholic"
stools occur when bile is deficient, either from obstruction to
outflow or from deficient secretion. The color is due less to absence
of bile-pigments than to presence of fat. Similar stools are common in
conditions like tuberculous peritonitis, which interfere with
absorption of fats, and in pancreatic disease.
Notable amounts of blood produce tarry black stools when the source of
the hemorrhage is the stomach or upper intestine, and a dark brown or
bright red as the source is nearer the rectum. When diarrhea exists,
the color may be red, even if the source of the blood is high up. Red
streaks of blood upon the outside of the stool are due to lesions of
rectum or anus.
5. Odor.--Products of decomposition, chiefly indol and skatol, are
responsible for the normal offensive odor. A sour odor is normal for
nursing infants, and is noted in mild diarrheas of older children. In
the severe diarrheas of childhood a putrid odor is common. In adults
stools emitting a very foul stench are suggestive of malignant or
syphilitic ulceration of the rectum or gangrenous dysentery.
6. Mucus.--Excessive quantities of mucus are easily detected with the
naked eye, and signify irritation or inflammation. When the mucus is
small in amount and intimately mixed with the stool, the trouble is
probably in the small intestine. Larger amounts, not well mixed with
fecal matter, indicate inflammation of the large intestine. Stools
composed almost wholly of mucus and streaked with blood are the rule
in dysentery, ileocolitis, and intussusception. In the so-called
mucous colic, or membranous enteritis, shreds and ribbons of altered
mucus, sometimes representing complete casts of the bowel, are passed.
{238} 7. Concretions.--Gall-stones are probably more common than is
generally supposed, and should be searched for in every case of
obscure colicky abdominal pain. Intestinal concretions (enteroliths)
are rare.
Concretions can be found by breaking up the fecal matter in a sieve
(which may be improvised from gauze) while pouring water over it. It
must be remembered that gall-stones, if soft, may go to pieces in the
bowel.
8. Animal Parasites.--Segments of tape-worms and the adults and larvæ
of other parasites are often found in the stool. They are best
searched for in the manner described for concretions. The search
should be preceded by a vermicide and a brisk purge. Patients
frequently mistake vegetable tissue (long fibers from poorly
masticated celery or "greens," cells from orange, etc.) for intestinal
parasites, and the writer has known physicians to make similar
mistakes. Even slight familiarity with the microscopic structure of
vegetable tissue will prevent the chagrin of such errors.
II. CHEMIC EXAMINATION
Complicated chemic examinations are of little value to the clinician.
Certain tests are, however, important.
1. Blood.--When present in large amount, blood produces such changes
in the appearance of the stool that it is not likely to be overlooked.
Traces of blood (occult hemorrhage) can be detected only by special
tests. Recognition of occult hemorrhage has its greatest value in
diagnosis of gastric cancer and ulcer. It is constantly present in
practically every case of gastric cancer, and is always present,
although usually intermittently, in ulcer. Traces of blood also
accompany malignant disease of the {239} bowel, the presence of
certain intestinal parasites, and other conditions.
* * * * *
Detection of Occult Hemorrhage.--Soften a portion of the stool with
water, treat with about one-third its volume of glacial acetic acid,
and extract with ether. Should the ether not separate well, add a
little alcohol. Apply the guaiac test to the ether as already
described (p. 89).
In every case iron-containing medicines must be stopped, and
blood-pigment must be excluded from the food by giving an appropriate
diet, _e.g._, bread, milk, eggs, and fruit. At the beginning of the
restricted diet give a dram of powdered charcoal, or 7 grains of
carmin, so as to mark the corresponding stool.
* * * * *
2. Bile.--Normally, unaltered bile-pigment is never present in the
feces of adults. In catarrhal conditions of the small intestine
bilirubin may be carried through unchanged. It may be demonstrated by
filtering (after mixing with water if the stool be solid) and testing
the filtrate by Gmelin's method, as described under The Urine.
III. MICROSCOPIC EXAMINATION
Care must be exercised in selection of portions for examination. A
random search will often reveal nothing of interest. A small bit of
the stool, or any suspicious-looking particle, is placed upon a slide,
softened with water if necessary, and pressed out into a thin layer
with a cover-glass. A large slide--about 2 by 3 inches--with a
correspondingly large cover will be found convenient. Most of the
structures which it is desired to see can be found with a two-thirds
objective. Details of structure must be studied with a higher power.
{240} The bulk of the stool consists of granular débris. Among the
recognizable structures met in normal and pathologic conditions are:
remnants of food, epithelial cells, pus-corpuscles, red
blood-corpuscles, crystals, bacteria, and ova of animal parasites
(Fig. 90).
[Illustration: FIG. 90.--Microscopic elements of normal feces: _a_,
Muscle-fibers; _b_, connective tissue; _c_, epithelial cells; _d_,
white blood-corpuscles; _e_, spiral vessels of plants; _f_-_h_,
vegetable cells; _i_, plant hairs; _k_, triple phosphate crystals;
_l_, stone cells. Scattered among these elements are micro-organisms
and débris (after v. Jaksch).]
1. Remnants of Food.--These include a great variety of structures
which are very confusing to the student. Considerable study of normal
feces is necessary for their recognition.
_Vegetable fibers_ are generally recognized from their spiral
structure; _vegetable cells_, from their double contour and the
chlorophyl bodies which many of them contain. These cells are apt to
be mistaken for the ova of parasites. _Starch-granules_ sometimes
retain their original form, but are ordinarily not to be recognized
except by their staining reaction. They strike a blue color with
Lugol's solution when undigested; a red color, when slightly digested.
_Muscle-fibers_ are yellow, and sometimes appear as short, {241}
transversely striated cylinders with rather squarely broken ends.
Generally, the ends are rounded and the striations faint, or only
irregularly round or oval yellow masses are found. _Curds of milk_ are
especially important in the stools of children. They must be
distinguished from small masses of _fat_. The latter are soluble in
ether, and stain red with Sudan III.
Excess of any of these structures may result from excessive ingestion
or deficient intestinal digestion.
2. Epithelial Cells.--A few cells derived from the wall of the
alimentary canal are a constant finding. They show all stages of
degeneration, and are often unrecognizable. A marked excess has its
origin in a catarrhal condition of some part of the bowel. Squamous
cells come from the anal orifice; otherwise the form of the cells
gives no clue to the location of the lesion.
3. Pus.--Amounts of pus sufficient to be recognized with the eye alone
indicate rupture of an abscess into the bowel. If well mixed with the
stool, the source is high up, but in such cases the pus is apt to be
more or less completely digested, and hence unrecognizable. Small
amounts, detected only by the microscope, are present in catarrhal and
ulcerative conditions of the intestine, the number of pus-cells
corresponding to the severity and extent of the process.
4. Blood-corpuscles.--Unaltered red corpuscles are rarely found unless
their source is near the anus. Ordinarily, only masses of
blood-pigment can be seen. Blood is best recognized by the chemic
tests (p. 239).
5. Bacteria.--In health, bacteria constitute about one-third of the
weight of the dried stool. They are beneficial to the organism,
although not actually necessary {242} to its existence. It is both
difficult and unprofitable to identify them. The great majority belong
to the colon bacillus group, and are negative to Gram's method of
staining.
In some pathologic conditions the character of the intestinal flora
changes so that Gram-staining bacteria very greatly predominate. As
shown by R. Schmidt, of Neusser's clinic in Vienna, this change is
most constant and most striking in cancer of the stomach, owing to
large numbers of Boas-Oppler bacilli, and is of considerable value in
diagnosis. He believes that a diagnosis of gastric carcinoma should be
very unwillingly made with an exclusively "Gram-negative" stool, while
a "Gram-positive" stool, due to bacilli (which should also stain brown
with Lugol's solution), may be taken as very strong evidence of
cancer. A Gram-positive stool due to cocci is suggestive of intestinal
ulceration. The technic is the same as when Gram's method is applied
to other material (p. 40), except that the smear is fixed by immersion
in methyl-alcohol for five minutes instead of by heat. Fuchsin is the
best counter-stain. The deep-purple Gram-staining bacteria stand out
much more prominently than the pale-red Gram-negative organisms, and
one may be misled into thinking them more numerous even in cases in
which they are much in the minority. The number of Boas-Oppler bacilli
can be increased by administering a few ounces of sugar of milk the
day before the examination.
Owing to the difficulty of excluding swallowed sputum, the presence of
the tubercle bacillus is less significant in the feces than in other
material. It may, however, be taken as evidence of intestinal
tuberculosis when clinical signs indicate an intestinal lesion and
reasonable care is {243} exercised in regard to the sputum. Success in
the search will depend largely upon careful selection of the portion
examined. A random search will almost surely fail. Whitish or grayish
flakes of mucus or blood-stained or purulent particles should be
spread upon slides or covers and stained by the method given upon p.
127. In the case of rectal ulcers, swabs can be made directly from the
ulcerated surface.
6. Crystals.--Various crystals may be found, but few have any
significance. Slender, needle-like crystals of fatty acids and soaps
(Fig. 32) and triple phosphate crystals (Fig. 90) are common.
Characteristic octahedral crystals of calcium oxalate (Fig. 47) appear
after ingestion of certain vegetables. Charcot-Leyden crystals (Fig.
6) are not infrequently encountered, and strongly suggest the presence
of intestinal parasites. Yellowish or brown, needle-like or rhombic
crystals of hematoidin (Fig. 32) may be seen after hemorrhage into the
bowel.
7. Ova of Parasites.--The stool should be well mixed with water and
allowed to settle. The ova will be found in the upper or middle
portions of the sediment. Descriptions will be found in the following
chapter.
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