DISHARMONIES IN THE ORGANISATION OF THE DIGESTIVE SYSTEM OF MAN
Perfection of the human form—The covering of hair—The dentition in
general and the wisdom teeth—The vermiform appendage—Appendicitis and
its gravity—Uselessness of the cæcum and of the large
intestine—Instance of a woman without a large intestine—Ancestral
history of this portion of the digestive tract—Injurious effect of the
microbes of the large intestine—Frequency of cancer of the large
intestine and of the stomach—Limited usefulness of the stomach—The
instinct of choice of food—Futility of this instinct in man
Although he is a recent arrival on the earth, man has made great
progress as compared with his ancestors, the anthropoid apes. A
comparison between even the lower races of man, such as the Hottentots
or the aborigines of Australia and higher types such as the inhabitants
of Europe and of North Africa, shows that a very great advance has been
made.
Human art has been able to surpass nature in many instances. No natural
sound is so perfect as some of the more beautiful pieces of modern
music. Even in the production of form, man has triumphed over nature.
Breeders of flowers or of birds seek to produce new varieties. With this
object they often frame a conception of what they desire to produce,
and, so to speak, set about to realise their programme. They prepare
ideal images to serve them as guides in the process of production. By
the method of artificial selection they often succeed in their wishes,
and add to their collections some remarkable form. In such fashions
aviculture and horticulture have produced birds and flowers more
beautiful than any found in nature.
In regard to the human body, attempts have been made to surpass nature
and to represent a body corresponding to an artistic ideal. To arrive at
something more beautiful than man, the wings of birds or the characters
of some other creatures have been added to his presentment. Such
attempts have had no other result than to show that the human form, as
created by nature, cannot be surpassed. The ancient conception of the
human body as the artistic ideal has been fully justified. The views of
those religious fanatics who have thrown contempt on the body by
representing it in degraded forms, must be rejected.
It is impossible, however, to apply this result to our conception of the
nature of man in general. The beautiful form of the human body appears
only in youth and in maturity. In old age, the bodies of men and women
are generally ugly, and in extreme old age it is almost impossible to
see the traces of former beauty.
Nor can conceptions of perfection drawn from the human face and body be
extended to the whole of man’s organisation. A glance at some of the
organic systems will make this plain.
The human skin is covered with little hairs, the history of which is
interesting. In one stage of embryonic life nearly the whole of the body
is clad with hairs. This covering is known as the _lanugo_, and consists
of strands of hair, disposed very regularly all over the body, save on
the nose and the hands and feet. There is no doubt but that this is
functionless, and is no more than an inheritance from the old ape-like
condition. Later on, it falls out and is replaced by the ordinary downy
covering of the body. In adult life, and particularly in old age, the
hairs of the second coat tend to grow very long and so to form a
covering that is neither beautiful nor in the least degree useful. We
may take this as a first example of a disharmonious condition in the
human body. Hairs, incapable of protecting the body from cold, survive
merely as an ancestral relic and may become even harmful.
The human skin is constantly exposed to the microbes in dust; and the
follicles of the hairs, in which these microbes lodge, form receptacles
very favourable to their multiplication. In the hollows of the
follicles, certain microbes, as for instance some of the
_Staphylococci_, multiply rapidly and give rise to acne and to pimples.
The process may even go the length of producing a chronic skin-disease
very unpleasant and even dangerous if it be associated with suppuration.
In the human race, intelligence, that is to say, the activity of the
brain, supplants many other functions, and man is able to protect
himself against the inclemencies of weather much better than his furry
ancestors were capable of doing. He is able to do this through his
invention of clothing which may be varied with the nature of the
weather. But the obstinate laws of inheritance burden him with a
covering of hair, not only useless but frequently harmful. And this is
only one example among many.
Although, in an extreme case, man is able to survive the total loss of
the teeth, it cannot yet be said that teeth are useless or harmful. None
the less, a study of the human dentition reveals that this set of organs
is out of harmony with the fundamental needs of our race. The monkeys of
the old world (_Catarrhines_), although they belong obviously to the
brute creation, already exhibit a tendency to reduction in the number of
teeth. While American monkeys (_Platyrrhines_) may possess thirty-six
teeth, the old world forms do not possess more than thirty-two in all,
at least as a normal occurrence. Selenka[67] has shown that among
gorillas and ourangs individuals with a fourth pair of molars, bringing
up the number of teeth to thirty-six, are not rare. He found these
additional molars in 20 per cent. of one hundred and ninety-four adult
skulls of ourangs. On the other hand, in the cases of the chimpanzee and
the gibbon, the third pair of molars differ from the others in smaller
size and occasional absence. This reduction is to be associated with the
smaller jaws and less powerful mastication of these anthropoids.
Cases of supplementary molars are very rare in man, and occur more
frequently in the lower races, such as negroes, Australians, and natives
of New Caledonia.[68] On the other hand, absence of the third pair of
molars, that is to say, of the wisdom teeth, is quite frequent,
especially in the white races. Nearly 10 per cent. of Europeans
throughout their lives have no more than twenty-eight teeth, the wisdom
teeth being absent. This absence is more common in the upper jaw, where
it occurs in from 18 to 19 per cent. of men. The loss of the wisdom
teeth[69] is on the whole to be regarded as an advantage. Certainly from
the “physiological point of view the part played by the wisdom teeth is
subordinate. Their power of masticating is feeble; the loss does not
appreciably interfere with mastication. The complete absence of all four
has no influence on mastication.”[70] These teeth are cut very late,
often not appearing until the thirtieth year and sometimes being delayed
to extreme old age.
Even if they were only useless, the wisdom teeth would furnish an
instance of disharmony in the human body. But these teeth often are a
source of trouble which, although it is not often serious, may lead to
grave diseases and even to death. No other teeth are so subject to
accident. This is due partly to the slowness with which they develop and
to the difficulty they encounter in cutting the mucous membrane. Dental
caries, moreover, is specially frequent in them.[71] The membrane
surrounding them is specially subject to small lesions by which the
infection spreads to adjacent parts. Inflammatory conditions frequently
arise from these teeth, and tumours, caries of the jaw-bone and even
diffused suppuration, leading to death, may be sequelæ of wounds of the
wisdom teeth. Galippe[72] has described a case in which one of these
teeth, failing to cut the gum in the normal position, made its way
through the cheek. This produced an inflammatory suppuration of the
cheek with numerous fistulæ and an inflammation of the masseter muscle
which made it impossible for the mouth to open. Notwithstanding the
extraction of the wisdom tooth that had been the cause of all these
troubles, the patient died of meningitis, which had started from the
tooth. Other cases have been described in which a difficult eruption of
the tooth led to formation of an abscess in the bone, from which there
arose a fatal abscess of the brain.
Wisdom teeth may be the starting-point even of cancerous tumours.
Magitot[73] writes that very many neoplasms of the jaw may be traced to
a source of origin in the socket of the wisdom tooth.
There is no useful function of these teeth to set against their
disadvantages. It was our remote ancestors, masticating hard food, that
had the advantages of these additional teeth. In man they are
rudimentary organs, and provide another proof of our simian origin.
The cæcal or vermiform appendage is another rudimentary organ in the
human body, and is interesting from many points of view. I have already
referred to its importance as definite evidence of our origin from lower
animals, and shown how striking is the resemblance of the human organ to
that of the anthropoid apes. It consists of a thick wall, containing
glands, a muscular layer and lymphoid clumps. That it performs no
function useful to man is made clear by the existence of undisturbed
health in persons from whom it has been removed. Thanks to the advances
of modern surgery, this organ has been removed very often, and sometimes
even in cases where it did not appear to have been diseased. In a great
majority of the cases, the removal of the organ succeeded well, and the
patients experienced no harm, but appeared to carry on all the processes
of digestion with equal completeness.
On the other hand, the cæcal appendage in man is frequently obliterated,
there being no trace of the normal aperture, so that there is no
connection between it and the general digestive cavity. According to
Ribbert,[74] nearly one person in four possesses the appendage in an
obliterated condition, the condition being particularly frequent in the
aged. In young persons and infants the aperture of the appendage is
usually open. In cases where there is no communication with the cavity
of the digestive tract, the processes of digestion appear to be normal.
It is logical to conclude that in the human being the function of the
cæcum is either absent or very slight.
Even in the anthropoid apes the appendage of the cæcum appears to be a
rudimentary structure, with a function at most accessory to that of the
lymphoid clumps. In lower old world monkeys the vermiform appendage does
not usually exist, cases such as that of _Cercopithecus sabaeus_, in
which it is present as a little boss, being rare. It is necessary to
seek the purpose of this structure still lower in the scale of life. In
some herbivorous creatures the cæcum is large, and ends in a portion
richly provided with lymphoid tissue, and similar to the vermiform
appendage. The rabbit and certain marsupials are good examples.
Undoubtedly, in their cases, the portion of the digestive canal which
corresponds to the vermiform appendage of man is active in the digestion
of vegetable matter. The organ is a very old part of the constitution of
mammals, and it is because it has been preserved long after its function
has disappeared that we find it occurring in the body of man.
Rudimentary organs for the most part display a congenital lack of the
power of resistance, and, as Darwin suggested, for this reason they are
frequently the seats of disease. When Darwin wrote his work on the
“Descent of Man,” more than a quarter of a century ago, many fatal cases
of inflammation of the appendage had not been recorded. Darwin quoted
only two cases as known to him. Since then, appendicitis (the name given
by American surgeons to the first acute or to the chronic inflammation
of the appendage) has become a well-known disease in Europe and America,
and occupies considerable space in treatises on the pathology of the
digestive tract.
To give an idea of the prevalence of appendicitis, I may mention that in
a single Paris hospital (Hôpital Trousseau) four hundred and forty-three
cases of the disease have been treated in the five years 1895–1899.[75]
In many of these cases the subjects were infants, as these as a rule are
much more subject to appendicitis than are the aged. According to
Treves,[76] the well-known English surgeon, 36 per cent. of the observed
cases were under twenty years of age. Among old men, on the other hand,
appendicitis is a rare exception. The varying incidence of the disease
at different ages no doubt depends on the fact that in old age the
appendage is often obliterated. The more easy communication with the
other portion of the gut may be, the more chance there is for
inflammation to occur. As it has a muscular layer, the appendage is able
to void its fœcal contents; and a Scotch surgeon, Parker Syms,[77] has
seen an appendage that he had removed, in the act of writhing about like
an earthworm. Such movements, undoubtedly, would aid the discharge of
the contents of the cavity.
The movements of the appendage, however, are usually feeble, and thus
stagnation of the contents is common. Foreign matter is often found in
the cavity, such as the pips of fruit, seeds, hairs, thorns, and in rare
cases pins or even tin-tacks. Such bodies are capable of wounding the
inner wall of the appendage, and so giving an opportunity to the
microbes that abound in the digestive tube, with the result that
microbial infection and inflammation of the organ is produced. Often,
too, intestinal worms pass into the appendage and become the carriers of
pathogenic organisms.
Appendicitis is usually a grave disease, and is fatal in from 8 to 10
per cent. of cases. It would be difficult to find anywhere else in the
human body so flagrant a case of natural disharmony. The organ in
question may be obliterated or removed without disturbance of function,
and, moreover, in its normal condition is a frequent cause of serious
illness!
The vermiform appendage is not the only part of the digestive canal that
is out of harmony with the maintenance of life and health. The cæcum
itself, of which the appendage is only a portion, is degenerating in the
human body, as I stated in the last chapter. The human cæcum, in fact,
is very little developed in comparison with the cæcum of most
herbivorous animals, in which it is a true organ of digestion. In the
human embryo the cæcum and the appendage are relatively better developed
than they are in the adult.
Disharmony is exhibited in the human body not only by rudimentary organs
such as the wisdom teeth and the appendage, or by degenerating organs
such as the cæcum. Some very large parts of our alimentary canal must be
regarded as useless inheritances, bequeathed to us by our animal
ancestors. It is no longer rash to say that not only the rudimentary
appendage and the cæcum but the whole of the large intestine are
superfluous, and that their removal would be attended with happy
results. So far as digestion goes, the latter portion of the alimentary
tract is of little importance. Even from the point of view of absorption
of the products of digestion its importance is strictly secondary. And
so it is not astonishing to find that the removal or disappearance of
nearly the whole of the large intestine can be supported well by man.
As one result of the astonishing progress of surgery, it has been found
possible to excise certain parts of the gut, and particularly of the
large intestine. Thus, in one case, Körte[78] removed, along with part
of the small intestine, a considerable part of the large intestine,
leaving in place only the terminal portion. The patient, who underwent
eight successive abdominal operations, recovered. In the case[79] of
another patient, operated on by Wiesinger, two coils of the large
intestine (the transverse and descending colons) which were ulcerated,
were isolated from the remainder of the gut, while the upper portion of
the large intestine (the cæcum and the ascending colon) was sutured to
the rectum. In spite of these serious interferences with natural
structure, the patients recovered, and appeared to derive great
advantage from the loss of the large intestine.
I have quoted only two out of many similar cases. However, apart from
surgical evidence, there exists proof of the uselessness of the large
intestine in man. The best argument in favour of the proposition may be
drawn from the case of a woman who for thirty-seven years discharged the
waste matter from the alimentary canal through an intestinal fistula.
The latter had opened spontaneously, as the result of an abscess seated
on the right side of the abdomen. Her complaint, however, had not
prevented her from marrying, from bearing three children, nor from
pursuing an arduous calling. The person in question, who was a workwoman
in Varsovie, was examined by a surgeon, M. Ciechomski,[80] thirty-five
years after the establishment of the fistula. The surgeon proposed to
operate, hoping to restore her to the normal condition, and the woman
consented. However, when the abdominal cavity was opened, it appeared
that the large intestine had atrophied along the whole length, from the
cæcum to the rectum; the inner orifice of the fistula had passed into
the digestive tract above the cæcum, opening into the small intestine.
In the circumstances it was impossible to close the fistula, and the
surgeon had to close up the abdominal wall, leaving the patient in her
former condition. The woman recovered rapidly, and continued her usual
mode of life. She came under observation again two years later, but
since then had been lost sight of. The fact that a human being was
capable of carrying on an apparently normal life for thirty years in the
absence of a large intestine is good proof that the organ in question is
not necessary to man, although it has not yet become rudimentary. In
this case again, to find the useful stage of the structure, we have to
go to our remote ancestors.
The large intestine is much better developed in most herbivorous mammals
than it is in carnivorous forms. Although it is useless in the digestion
of animal food, it has an undisputed importance in the digestion of
vegetable matter. It has a very large calibre in herbivorous creatures,
and the voluminous cavity contains quantities of microbes which are able
to digest cellulose. As cellulose is a material that resists the
ordinary processes of digestion, it is easy to see the advantage derived
from the harbouring of the microbes. It is more than probable that in
the horse, the rabbit, and in some other mammals, that live exclusively
on grain and herbage, the large intestine is necessary for normal life.
On the other hand, the large intestine discharges a function similar to
that of the urinary bladder. The urine, which is being secreted
continuously by the kidneys, accumulates in the large reservoir provided
by the bladder. Similarly the waste matter from the processes of
digestion accumulate in the large intestine and remain there for a
longer or shorter period.
In studying the natural history of the large intestine, it striking that
this portion of the gut is well developed only among mammals. These
animals, for the most part, lead an extremely active terrestrial life.
Most of them have to move about very quickly, the predacious forms in
pursuit of their prey, the herbivorous forms to escape from their
enemies. In such a mode of life, the need to stop in order to empty the
intestines would be a serious disadvantage, and the possibility of
retaining the dejecta in a large reservoir would be very useful.[81]
Such are the causes that have determined the growth of the large
intestine among mammals. Birds, which live, so to speak, in the air, and
which do not need to arrest their locomotion in order to void their
excreta, have no large intestine. Reptiles and amphibia, although they
live a terrestrial life, do not require a voluminous large intestine,
and such is not found among them. These animals do not have a fixed
temperature; they are what we know as “cold-blooded,” and in consequence
are small eaters. Most of them are sluggish, and do not lead an active
existence like that of mammals.
In the legacy acquired by man from his animal ancestors, there occur not
only rudimentary organs that are useless or harmful, but fully developed
organs equally useless. The large intestine must be regarded as one of
the organs possessed by man and yet harmful to his health and his life.
The large intestine is the reservoir of the waste of the digestive
processes, and this waste stagnates long enough to putrefy. The products
of putrefaction are harmful. When fæcal matter is allowed to remain in
the intestine, as in cases of constipation, a common complaint, certain
products are absorbed by the organism and produce poisoning, often of a
serious nature. Every one knows that a high temperature may be the
result of constipation in women after childbirth, or in patients
recovering from an operation. This is due to an absorption of substances
produced by the microbes of the large intestine. Similar products may be
the cause of an attack of acne or of other skin diseases. In fine, the
presence of a large intestine in the human body is the cause of a series
of misfortunes. The organ is the seat of many grave diseases, among
which dysentery is notable. In some tropical climates dysentery is a
serious scourge. According to Rhey,[82] it is “the greatest danger to
which a European is subjected in Tonkin. It is responsible for more than
30 per cent. of the deaths caused by disease.” European troops pay it a
large annual toll in the colonies of the French and English.
Malignant tumours seem to display a predilection for this region of the
digestive tract. Thus, among 1148 cases of cancer of the alimentary
tract recorded in the Prussian hospitals in 1895 and 1896, 1022, or 89
per cent., affected the large intestine, including the rectum and
cæcum.[83] The small intestine is the only part of the digestive tract
that is indispensable, and it is attacked to a much smaller extent,
providing only 11 per cent. of the cases of intestinal cancer. The
probable explanation of these facts is that the contents of the gut
remain in the small intestine a shorter time than in the large.
Stagnation is a familiar cause of disease, and is the probable cause of
the frequency of cancer of the stomach. Of 10,537 cases of cancer of all
parts of the digestive tract recorded in the Prussian hospitals in the
same period, 4288, or more than 40 per cent., affected the stomach. The
latter organ is one that the human body would do well to be rid of. It
is not so useless as the large intestine, since it is the chief seat of
digestion of albuminous substances, but the small intestine could take
its place. Moreover, cases are known in which surgeons have removed
cancerous stomachs. The results of such operations were favourable, to
the extent that the patients survived and were able to absorb sufficient
nourishment. They had to eat rather more frequently, and performed the
processes of digestion by means of the secretions of the small intestine
and pancreas.
It is not surprising to find so many instances of useless or harmful
organs in the alimentary tract. Our ancestors were creatures that fed on
crude and rough materials, such as wild plants and unprepared flesh. Man
has learned to cultivate plants that are digested easily, and to prepare
his meats in such a fashion as to be readily digested. The organs that
were adapted to the mode of life of the animal predecessors of man have
become to a large extent superfluous. Many creatures that have found the
opportunity of obtaining their nutriment in a highly digestible
condition have lost, more or less completely, the digestive organs. Many
parasites are instances of this, as for example the tape-worms, which
live in the human digestive tract, bathed by a nutritive fluid which
they absorb directly; they have lost the digestive tract completely.
In the case of man such an evolution has not occurred, and there remains
in the body a harmful organ like the large intestine. In consequence, it
is impossible for him to take his nutriment in the most perfect form. If
he were only to eat substances that could be almost completely absorbed,
the large intestine would be unable to empty itself, and serious
complications would be produced. A satisfactory system of diet has to
make allowance for this, and in consequence of the structure of the
alimentary canal, has to include in the food bulky and indigestible
materials such as vegetables.
At this point I may refer to a topic of considerable general interest.
Animals, in the choice of food for themselves or for their young, are
guided by a blind and innate instinct. As I have shown in my second
chapter, creatures like the fossorial wasps select only particular
species of spiders or insects. Instinct directs them to the kind of food
best suited to the wants of their progeny. Bees are attracted by the
sweet juices of flowers; the silkworm instinctively devours the leaves
of the mulberry and rejects most other plants. In higher animals,
instinct plays the chief part in the choice of food. The difficulty of
getting rats to eat poisoned food is well known; an instinct warns them
of the danger of the material offered to them. In the same way dogs
refrain from food that has been poisoned.
Every one has seen the minute attention bestowed by a monkey on food
before beginning to eat it. It turns over what is offered, smells it
carefully, cleans it, and before beginning to eat, subjects it to an
examination that seems to us ridiculous. Monkeys often throw away food
without even biting it. None the less, in spite of an instinct so highly
developed, monkeys poison themselves with all sorts of dangerous
substances, even when these exhale a strange odour. I have seen monkeys
die poisoned by the phosphorus of matches, or even by iodoform which
they had contrived to steal.
In the case of man, aberrations of instinct in the choice of food are
common. As soon as babies begin to walk, they lay hold of everything and
try to eat it. Bits of paper, lumps of sealing-wax, the mucous matter
from the nose, all appear to them to be things to eat. Constant guard
has to be kept to prevent them from doing themselves an injury. Fruits
and berries they cannot resist. Cases of poisoning very naturally are
extremely frequent, and as every one must know of instances, I shall
mention only a single case. “Messrs. Beadle and Sons, oil manufacturers
at Boston, had thrown out, from the door of their establishment, a
quantity of castor beans that were decayed and useless. Some children
playing in the street mistook the seeds for pistachio nuts, and shared
them with their friends. All the children seem to have eaten of them,
with the result that more than seventy showed serious symptoms of
poisoning.”[84]
The consumption of ergotised rye and of maize contaminated with certain
leguminous plants (_Lathyrus_) frequently produces epidemics of
poisoning without instinct intervening to protect the victims.
While the large intestine, acting as an asylum of harmful microbes, is a
source of intoxication from within, the aberrant instinct of man leads
him to poison himself from without with alcohol and ether, opium and
morphia. The widespread results of alcoholism show plainly the prevalent
existence in man of a want of harmony between the instinct for choosing
food and the instinct of preservation.
The digestive apparatus, then, affords abundant proof of the
imperfection and disharmony of our nature. Moreover, there are many
other proofs, as I shall show in the chapters to follow.