CHAPTER IV

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.