It was the renowned Metchnikoff, I believe, who considered the digestive organs a grossly over-developed system in the human economy. Certainly, many of his less accomplished successors predict the future man with a very reduced digestive apparatus, sufficient only to absorb The ladies may take pleasure in contemplating that it will have taken the males 500,000 years to attain the smoothness of brow which they now possess. highly concentrated food—pills with which they fancy man will content himself. Perhaps even such a vestigial digestive tract may be dispensed with altogether if man ever becomes indifferent to food. In that sad day the essential nutriment of life might then be injected directly into the blood stream. But I cannot accept this dismal future. The delights of the table are too pleasant to be lightly eliminated in favor of the sterile and joyless consumption of food pills. I can perceive no diminution in man’s appetite—if anything he eats more than primitive man—and certainly I have yet to know a healthy man who shows even the faintest inclination to relinquish the sensuous and delicate enjoyment of solid foods. Therefore I leave you your stomach and its appurtenances.
But even though our digestive system remains intact, one adjunct to it is undergoing modifications and will continue to do so. This is the dentition. No vertebrate is afflicted with such extensive dental decay as is man. Hardly a child among us reaches puberty without some decay developing, few adolescents attain maturity without loss of teeth from caries, and a large number of adults only have teeth at all by the constant vigilance of the dentists.
Unfortunately decay, or caries, is not the only evidence of a serious readjustment going on in our dentition. This is seen also in the frequency with which our teeth are malerupted. Twisted teeth, impacted molars, faulty alignments and malocclusions are too common to be lightly dismissed. They indicate a deep-seated force at work which is generally affecting the population. Indeed, so numerous are the children suffering from these maleruptions that there has grown into being a branch of dentistry, orthodontia, devoted expressly to the correction of these dental faults.
Dental Modifications But this is not the whole story of the degeneration of the human dentition. In still other ways it manifests itself. I shall mention only two more. One is the increasing suppression of the third molars or wisdom teeth. Not only is the age at which is normally erupts, 18 to 20, being pushed back later and later in life, but in many people they are absent in whole or in part. The second is the constriction of the jaws. It is obvious that the crowding of the teeth and the constriction of the jaws may be associated, but not always is this the case.
Weakening Teeth One cannot help being convinced that all this evidence is symptomatic of a fundamental process which may in time be responsible for considerable alterations to our dental equipment. I do not propose to enunciate a dogmatic generalization to account for this situation. Controversies on the nature and cure of dental decay have flourished for generations among those interested in teeth. Decay has been attributed to hyperacidity, to endocrine dysfunction and to diet, among other factors. No doubt the situation is a complex one and the superficial causes may be as varied as the manifestations they produce. But one cannot but be impressed by the fact that the dentition is an area of weakness. My guess is that the teeth are, to a large extent, losing their function and consequently becoming less vigorous and resistant. In other words, they are readjusting themselves to the changed demands upon them. This in itself reduces them to a state of relative non-resistance which makes them especially prone to secondary attacks—endocrine dysfunction, faulty diet and hyperacidity. In their weakened state they are unable to withstand attacks that in lower forms are easily resisted. Perhaps I can make my idea clearer by comparing them to an army which, kept in constant and full use of its powers, is able to put up a good defense against its enemies. But suppose such an army were not systematically employed but took its ease in comfortable barracks and never exercised its warlike functions. Then an attack would decimate it. So the teeth have lost their resistance and so they capitulate to the onslaughts of their enemies.
Fewer and Smaller Teeth We may see this perhaps more clearly by examining the toughened teeth of anthropoids and early man. Of course, decay is not completely unknown even among these creatures, but it is rare. The third molars do in most cases erupt complete and sound, and the position and alignment of the teeth in their serried arches would delight the heart of an orthodontist, accustomed to the misshapen jaws of his patients. Even among present-day Eskimo who alone among living people make full use of their teeth the same beauty of dentition is present. From the primates to modern man Since it is improbable that we shall return to the tough, resistant food on which our predecessors thrived, the chances are that our dentitions will continue to deteriorate. we perceive a progressive recession of the jaws, a decrease in the size of teeth, a loss in number, and an increase in maleruptions.
We are now in the position to predict the future condition of the teeth of our gradually emerging man. Since it is improbable that we shall return to the tough, resistant food on which our predecessors thrived, the chances are that our dentitions will continue to deteriorate. Future man will have lost his third molars, many of them will also show reduced or absent lateral incisors. The jaws will be smaller and what teeth are present will be diminished in size.