To medical men in private practice the poor physical condition of present-day children is not likely to be so obvious as to one engaged in examining large numbers in the schools. The extreme rarity of a complete sound set of teeth and the great prevalence of deformity of the chest are indices of serious errors in their upbringing. The most serious and widespread physical defects found in New Zealand schoolchildren are dental caries, faulty development of the jaws and palate, nasal obstruction, adenoids and enlarged tonsils, and rachitic deformity of the chest. I am confident that these defects are due to the same fundamental causes, that these causes can be easily removed, and that, therefore, the vast majority of the diseases and defects from which children suffer are readily preventable. The causes are, I maintain, errors in nutrition, and consist in (1) the unnatural softness of foods, (2) deficiency of vitamines, and (3) deficiency of salts.

Let us consider faulty development of the jaws. It shows itself in crowding and irregularity of the teeth and malocclusion. Insufficient expansion of the upper jaw results in a narrow high arching of the palate, which is of necessity accompanied by narrow, poorly-expanded nostrils and deflection of the septum. The consequent tendency to nasal obstruction results in deficient ventilation and a moist, catarrhal state of the nasal passages. The catarrhal condition is increased by the irritation of mouth-breathing. Both these factors cause an unnaturally moist and sodden state of the nasal and post-nasal mucous membrane. This is admittedly a cause of chronic enlargement—analogous to exuberant granulations in a discharging wound—hence the polypoid overgrowth of the pharangeal tonsil which we call adenoids. Or the adenoid enlargement may be compensatory, to cope with the bacteria which inevitably accompany catarrh. Another theory is that the adenoids are primary and are in some way due to disturbance of the internal secretions; and that the adenoids lead to poor expansion of the nostrils, palate, and so on.

It is a clinical, fact that removal of adenoids and the establishment of nasal breathing tends to rectify under­development of the jaw, but I am confident of this—that under-development of the jaw due to deficient masticatory exercise is the primary condition.

Just as poor development of the upper jaw results consecutively in narrow nostrils, nasal obstruction, and adenoids, so also the resulting mouth-breathing, by irritating the respiratory passages, tends to increase the nasal obstruction, and the open mouth by traction on the cheeks tends to increase the narrowing of the jaws.

Again, irregularity of the teeth increases the tendency to the retention of food in the inter-dental crevices, and, therefore, increases the tendency to dental caries. Mouth­breathing, by causing dryness of the gums and teeth and putting into abeyance the cleansing action of the saliva, also increases dental caries. Faulty development of the jaws, being the cause of both dental irregularity and mouth-breathing, is, therefore, in these two ways a cause of dental caries. Also, the septic state resulting from dental caries undoubtedly contributes to a septic enlargement of the tonsils. Here, then, are many vicious circles reacting upon each other.

If, therefore, poor jaw development is directly and indirectly the cause or one of the causes of these evils, what is the cause of the poor jaw development? I believe that it is due chiefly to the first of the three dietetic deficiencies mentioned above—the unnatural softness of food. Lack of vigorous mastication, especially in the early growing years of childhood, results in poor development of the muscles of mastication, with consequent poor development of the bones to which they are attached. The pull of the masseter muscles in vigorous mastication undoubtedly has a widening effect on the lower jaw, and the actual biting force of mastication must tend to spread and widen the arch of the maxilla and palate. The pterygoid muscles of mastication are attached to the external pterygoid plate of the ethmoid, which is in close relation to the lateral wall of the naso-pharynx and to the palate bones which form the outer walls of the posterior part of the nostrils. The outward pull of the pterygoids, therefore, would seem to have a widening effect upon the naso-pharynx and on the posterior part of the nose, the parts which are so frequently narrowed and obstructed. Therefore, vigorous exercise of the jaws in masticating hard food contributes, in more ways than one, to well-developed jaws, a wide arch of the palate, and wide and roomy nostrils and naso-pharynx.

We are all familiar with the close association of narrow jaws, crowding of teeth, narrow, highly-arched palate, nasal obstruction and adenoids, but there is no general recognition of the lack of mastication and under-development of the jaws as the primary cause. We can bring a few additional arguments to bear on the problem.

The softness of modern food, especially of children’s food, is one of the most obvious departures from the natural in modern diet. It operates from about twelve months of age and continues throughout the whole period of growth. Surely the lack of this most natural exercise, for which every young child shows such an obvious craving, during a period most sensitive to habit and environment, is likely to have some marked developmental effect upon the structures concerned.

The undue sucking in bottle-feeding as contrasted with the munching of breast-feeding has also been shown to lead to a narrowing of the jaws. Dummies and thumb-sucking to, a much greater extent have the same effect, as well as being media for bacterial infection.

When we consider the massiveness of the muscles of mastication in comparison to the size of the bones to which they are attached, it is natural to expect that their vigorous exercise would have an important effect upon the circulation to, and development of, the jaws. Again, the greatest under-development is not in the upper but in the lower jaw, where one would expect it to be, as it is to it that the masticatory muscles are attached, the upper being stationary and passive. Owing to the peculiar interlocking of the teeth, I believe that dentists find the lower jaw is the primary one in which to correct deformity, as to a great extent it controls the shape of the upper.

Further, the actual size of the palate and the actual size of the nasal septum do not appear to be affected. Both these structures retain their natural dimensions, but through lack of space are compelled to undergo unnatural curvature. The primary developmental error seems to be, not in the nose and not in the palate, but in the jaws. The jaws are undersized; no part of the nasal structure is undersized, it is simply unexpanded. Surely this proves indisputably that the jaw condition is primary, and if this is not due to lack of hard food—lack of exercise of the jaw—what is it due to? There is a serious developmental flaw in the modern child’s jaw which fails to bring the individual teeth of the second set into their proper positions.

Now, I am not claiming to have discovered anything. Attention has been called to these matters by others whose opinions are worth more than mine—by Dr. Pickerill, Sim Wallace, Harry Campbell, and many others. I am merely reviewing the facts with a view to obtaining for them greater general recognition as the causes of these very far-reaching and widespread defects. If insufficient exercise of the jaws is causing these serious defects in children, surely the medical and dental professions should be in a position to recommend the remedy.

I might draw attention here to the close association between deformity of the jaw and adenoids on the one hand, and pigeon-breast and depression of the ribs on the other. While softness of bone makes these deformities possible, the resistance to inspiration caused by adenoids certainly contributes to depression of the chest-wall. And, conversely, the diminished respiratory power resulting from poor development of the chest renders the overcoming of nasal obstruction more difficult.

Passing on to the subject of dental caries, although there may be some doubt as to its immediate cause, I think there can be no doubt that a great predisposing cause is the poor quality and defective structure of the teeth themselves, so that they are unable to withstand the strain of modern oral conditions. Defective structure of the teeth has been shown by experiments on animals to result from diets deficient in vitamines, and, as teeth are composed chiefly of lime, the metabolism of mineral salts is a factor of great importance. In referring to mineral salts I mean their organic combinations in food, not inorganic mineral. The latter is comparatively unimportant and can in no way replace the former.

Most of our common foods are deficient in vitamines and mineral salts. Meat contains practically no lime: 99 per cent. of the lime in an animal is contained in the bones; and carnivorous animals, who depend altogether on animal food, eat the bones as well as the flesh. Wheat, whole rice, maize, and barley are valuable sources of vitamines and salts, but in the artificially refined and partial state in which they are now eaten—as white flour, polished rice, cornflour, and pearl barley—they are deprived of their germ and outer layers, and so lose all their vitamines and about 50 per cent. of their salts. In the common method of boiling vegetables an average of 40 per cent. of their potash and other salts is thrown down the sink. By carelessness in allowing vegetables to cook for an unduly long time, their vitamines are to a great extent destroyed. Sago, tapioca, and arrowroot consist of chemically or mechanically separated starch, and are deficient in vitamines and salts. The vitamines of the fruit in jam are completely devitalised by the prolonged cooking to which they are subjected. The same applies to sugar, which is chemically pure, and therefore a highly deficient and unbalanced food. All the common foods have been mentioned except oatmeal, milk and its products, fruit and honey, all of which are valuable for their vitamines and salts.

It is obvious, therefore, that the bulk of our diet is very deficient in these important constituents. Enough has been said by those who have done original work regarding the effects of deficiency of vitamines to indicate that their artificial removal is a dangerous procedure, and that it is impossible at present to estimate how much ill-health and lowered vitality are directly due to it.

With regard to mineral nutriment, Bunge says that lime and iron salts are those which are likely to be insufficient in ordinary diets. Sherman, of Columbia University, says that the usual diet is frequently deficient in lime. These deficiencies are calculated in terms of the adult requirement of calcium, but the growing child, whose bones and teeth are in process of calcification, requires more calcium in proportion to its weight than the adult. Hence to the child this deficiency is more serious.

The deficiency of lime would be serious enough in itself, but is rendered more so by the concurrent deficiency of other alkaline salts, as will be shown.

As a result of metabolism, acid substances are produced which have to be neutralised in the body. They are neutralised by the alkaline bases derived from food. Hence the great value of the alkaline salts of potassium and sodium, and of the vegetable and fruit acids, which are oxidised into alkaline carbonates.

Meat is relatively poor in basic salts. Meat contains sulphur and phosphorous compounds which by oxidisation in the body form sulphuric and phosphoric acids. According to Sherman, meat and eggs yield a considerable excess of acids. A diet in which the acid-forming elements greatly predominate must result in a withdrawal of fixed alkalies from the blood and tissues.

Now, in cooking vegetables we throw away 40 per cent. of these vegetable alkalies; and in New Zealand we eat an absurd excess of meat. What seems to be a matter of immense importance is this—that, under these circumstances, calcium, which is on its way to the building of bones and teeth, may be diverted into the neutralising of these acids, and in this way the calcification of bones and of dental enamel may be interfered with.

Not only is it possible by the depletion of the alkaline reserves of the body to divert calcium from bone construction, but, according to Voit, bone takes some part in the daily metabolism, and it is possible, on a diet deficient in mineral, for the lime in the bones to be withdrawn to neutralise the acids of metabolism. Bunge says that calcium more than any other inorganic element is likely to be deficient as a result of the change from mother’s milk to other food. It has been shown that the majority of American diets even for the adult are dangerously deficient in lime, and also in phosphorus—and what applies to American applies also to New Zealand diets, for they are practically the same.

It is now definitely established that in anaemia medicinal inorganic iron is not itself built into haemoglobin, but acts only as a stimulant to blood-formation from the organic iron compounds of food. The iron content of food, which according to Abderhalden is also dangerously low in the average diet, is therefore a matter of great importance. Everything points to the necessity of giving serious consideration to the mineral content of our diet, especially as degeneration in the structure and rapid decay of the teeth—one of the chief mineral-built organs in the body—has become such a veritable menace to national health.

I will quote a passage from Von Noorden, one of the strongest advocates of a liberal use of meat in the adult diet. He says: “The necessity of a generous supply of vegetables and fruits must be particularly emphasised. They are of the greatest importance for the normal development of the body and of all its functions. As far as children are concerned, we believe we could do better by following the diet of the most rigid vegetarians than by feeding the children as though they were carnivora, according to the bad custom which is still prevalent. If we limit the most important sources of iron—vegetables and fruits—we cause a certain sluggishness of blood formations and an entire lack of reserve iron such as is normally found in the liver, spleen, and bone marrow of healthy well-nourished individuals.”

In Sherman’s “Chemistry of Food and Nutrition” we find: “In an experimental dietary study in New York it was found that the free use of vegetables, whole wheat bread, and the cheaper sorts of fruit, with milk, but without meat, resulted in a gain of 30 per cent. in the iron content of the diet, while the protein, fuel value, and cost remained the same as in the ordinary mixed diet.” I make these quotations to emphasise the importance of the salts of vegetable foods as constituents of our diet.

The consideration of the causes of dental caries is not complete without reference to the effects of modern diet upon the flow of saliva and upon acid fermentation in the mouth. This subject has been fully dealt with by Dr. Pickerill, and I believe it to be of very great importance. I will confine myself to the observation that the same artificialities in diet which contribute to poorly-built teeth also have a depressing effect upon the flow of saliva. The lack of hard food, the undue moisture and pastiness of food, the lack of fibre, of raw vegetable juices and raw fruit, the excessive consumption of sugar and tea and sweet confectionery—all these factors depress the flow of saliva and contribute to the retention of food about the teeth. The high milling of cereals, the removal of so much mineral matter and flavour from vegetables by cooking, and the use of so many artificially separated and soft foods, not only produce badly­formed teeth and jaws, but also increase the virulence of the conditions they have to contend with in the mouth.

There may be some difference of opinion as to the exact modus operandi of how these defects of childhood are brought about, and I do not wish to insist too much on any particular theory. My main contention is that it is the artificial nature of the foods we eat—something in the food, or something which is not in it—that is responsible for these evidences of malnutrition. No one, I think, will disagree on this point—the fate of the Māori’s teeth in the course of about two generations is a clear proof of it.

I think you will agree with me, however, that we have very definite scientific reasons for urging the most radical dietetic reform. We know that the mineral and vitamine contents of foods are reduced by artificial processes. We know—if we know anything—that these deficiencies cause poor nutrition and poor development of bones and teeth; and at the same time these very defects are assuming gigantic proportions and threatening to undermine our national welfare. If the British Empire is to successfully withstand the storms of the future we must possess that indispensable foundation of national greatness, the health of the people. Food, of all matters, is the basis of health. We must have hard food, that we may learn the salutary virtue of mastication; we must have whole cereals—wheatmeal bread and unpolished rice; we must eat less meat; learn the value of fruits and vegetables, and above all, learn how to cook them; we must appreciate the value of uncooked foods—we must look after the salts and the vitamines. I do not know of any matter of more urgent and vital importance to the health of the country than this one of food.

Now, in this paper I have called your attention to matters which have already been written about by others, but which, from my experience in the medical inspection of school-children, I am very strongly of opinion deserve more serious consideration than they have up to the present received. As Superintendent of the School Medical Services I am concerned with the health of the rising generation. The medical inspectors of schools are apostles of health, endeavouring to educate the public in how to rear healthy, robust, and vigorous children. At the recent conference of our staff in Wellington a committee was formed to decide upon a uniform code of recommendations regarding children’s health, most of which are embodied in what I have already said. If any of our fraternity in private practice have other theories as to the causes of these defects, or can in any way assist us, we shall be very much indebted to them. It is our aim to lay the foundations of a healthier, a happier, and a more prosperous New Zealand; we want your help and co-operation in this great work.

P.S.—As a result of talking over some of these matters at the Medical Conference, I have modified my views slightly regarding the causes of maldevelopment of the jaws. While I still maintain that vigorous mastication has a very important effect upon the size and general growth of the jaws, I believe now that the actual shape of the jaw is controlled more by the moulding action of the lips and tongue. The muscles of mastication are attached to the posterior part of the jaws, whereas it is the anterior part of the alveoler arch which is so commonly narrowed and mis-shaped. I am inclined to think that the first factor in the vicious series is bottle-feeding and the dummy. These tend to push up the centre of the palate and to narrow the jaws by the constant sucking, thus producing the tendency to nasal obstruction. The resulting open mouth brings further narrowing pressure on the jaws, and the open relaxed lips allow the incisor teeth to be pressed forward. These forces, though slight, are acting constantly, and—like the ivy spray which pushes its way through a stone wall—would have a considerable effect upon the soft developing jawbone. Decay and early extraction of the temporary teeth are other important causes of undersized jaws.

To medical men in private practice the poor physical condition of present-day children is not likely to be so obvious as to one engaged in examining large numbers in the schools. The extreme rarity of a complete sound set of teeth and the great prevalence of deformity of the chest are indices of serious errors in their upbringing. The most serious and widespread physical defects found in New Zealand schoolchildren are dental caries, faulty development of the jaws and palate, nasal obstruction, adenoids and enlarged tonsils, and rachitic deformity of the chest. I am confident that these defects are due to the same fundamental causes, that these causes can be easily removed, and that, therefore, the vast majority of the diseases and defects from which children suffer are readily preventable. The causes are, I maintain, errors in nutrition, and consist in (1) the unnatural softness of foods, (2) deficiency of vitamines, and (3) deficiency of salts.

Let us consider faulty development of the jaws. It shows itself in crowding and irregularity of the teeth and malocclusion. Insufficient expansion of the upper jaw results in a narrow high arching of the palate, which is of necessity accompanied by narrow, poorly-expanded nostrils and deflection of the septum. The consequent tendency to nasal obstruction results in deficient ventilation and a moist, catarrhal state of the nasal passages. The catarrhal condition is increased by the irritation of mouth-breathing. Both these factors cause an unnaturally moist and sodden state of the nasal and post-nasal mucous membrane. This is admittedly a cause of chronic enlargement—analogous to exuberant granulations in a discharging wound—hence the polypoid overgrowth of the pharangeal tonsil which we call adenoids. Or the adenoid enlargement may be compensatory, to cope with the bacteria which inevitably accompany catarrh. Another theory is that the adenoids are primary and are in some way due to disturbance of the internal secretions; and that the adenoids lead to poor expansion of the nostrils, palate, and so on.

It is a clinical, fact that removal of adenoids and the establishment of nasal breathing tends to rectify under­development of the jaw, but I am confident of this—that under-development of the jaw due to deficient masticatory exercise is the primary condition.

Just as poor development of the upper jaw results consecutively in narrow nostrils, nasal obstruction, and adenoids, so also the resulting mouth-breathing, by irritating the respiratory passages, tends to increase the nasal obstruction, and the open mouth by traction on the cheeks tends to increase the narrowing of the jaws.

Again, irregularity of the teeth increases the tendency to the retention of food in the inter-dental crevices, and, therefore, increases the tendency to dental caries. Mouth­breathing, by causing dryness of the gums and teeth and putting into abeyance the cleansing action of the saliva, also increases dental caries. Faulty development of the jaws, being the cause of both dental irregularity and mouth-breathing, is, therefore, in these two ways a cause of dental caries. Also, the septic state resulting from dental caries undoubtedly contributes to a septic enlargement of the tonsils. Here, then, are many vicious circles reacting upon each other.

If, therefore, poor jaw development is directly and indirectly the cause or one of the causes of these evils, what is the cause of the poor jaw development? I believe that it is due chiefly to the first of the three dietetic deficiencies mentioned above—the unnatural softness of food. Lack of vigorous mastication, especially in the early growing years of childhood, results in poor development of the muscles of mastication, with consequent poor development of the bones to which they are attached. The pull of the masseter muscles in vigorous mastication undoubtedly has a widening effect on the lower jaw, and the actual biting force of mastication must tend to spread and widen the arch of the maxilla and palate. The pterygoid muscles of mastication are attached to the external pterygoid plate of the ethmoid, which is in close relation to the lateral wall of the naso-pharynx and to the palate bones which form the outer walls of the posterior part of the nostrils. The outward pull of the pterygoids, therefore, would seem to have a widening effect upon the naso-pharynx and on the posterior part of the nose, the parts which are so frequently narrowed and obstructed. Therefore, vigorous exercise of the jaws in masticating hard food contributes, in more ways than one, to well-developed jaws, a wide arch of the palate, and wide and roomy nostrils and naso-pharynx.

We are all familiar with the close association of narrow jaws, crowding of teeth, narrow, highly-arched palate, nasal obstruction and adenoids, but there is no general recognition of the lack of mastication and under-development of the jaws as the primary cause. We can bring a few additional arguments to bear on the problem.

The softness of modern food, especially of children’s food, is one of the most obvious departures from the natural in modern diet. It operates from about twelve months of age and continues throughout the whole period of growth. Surely the lack of this most natural exercise, for which every young child shows such an obvious craving, during a period most sensitive to habit and environment, is likely to have some marked developmental effect upon the structures concerned.

The undue sucking in bottle-feeding as contrasted with the munching of breast-feeding has also been shown to lead to a narrowing of the jaws. Dummies and thumb-sucking to, a much greater extent have the same effect, as well as being media for bacterial infection.

When we consider the massiveness of the muscles of mastication in comparison to the size of the bones to which they are attached, it is natural to expect that their vigorous exercise would have an important effect upon the circulation to, and development of, the jaws. Again, the greatest under-development is not in the upper but in the lower jaw, where one would expect it to be, as it is to it that the masticatory muscles are attached, the upper being stationary and passive. Owing to the peculiar interlocking of the teeth, I believe that dentists find the lower jaw is the primary one in which to correct deformity, as to a great extent it controls the shape of the upper.

Further, the actual size of the palate and the actual size of the nasal septum do not appear to be affected. Both these structures retain their natural dimensions, but through lack of space are compelled to undergo unnatural curvature. The primary developmental error seems to be, not in the nose and not in the palate, but in the jaws. The jaws are undersized; no part of the nasal structure is undersized, it is simply unexpanded. Surely this proves indisputably that the jaw condition is primary, and if this is not due to lack of hard food—lack of exercise of the jaw—what is it due to? There is a serious developmental flaw in the modern child’s jaw which fails to bring the individual teeth of the second set into their proper positions.

Now, I am not claiming to have discovered anything. Attention has been called to these matters by others whose opinions are worth more than mine—by Dr. Pickerill, Sim Wallace, Harry Campbell, and many others. I am merely reviewing the facts with a view to obtaining for them greater general recognition as the causes of these very far-reaching and widespread defects. If insufficient exercise of the jaws is causing these serious defects in children, surely the medical and dental professions should be in a position to recommend the remedy.

I might draw attention here to the close association between deformity of the jaw and adenoids on the one hand, and pigeon-breast and depression of the ribs on the other. While softness of bone makes these deformities possible, the resistance to inspiration caused by adenoids certainly contributes to depression of the chest-wall. And, conversely, the diminished respiratory power resulting from poor development of the chest renders the overcoming of nasal obstruction more difficult.

Passing on to the subject of dental caries, although there may be some doubt as to its immediate cause, I think there can be no doubt that a great predisposing cause is the poor quality and defective structure of the teeth themselves, so that they are unable to withstand the strain of modern oral conditions. Defective structure of the teeth has been shown by experiments on animals to result from diets deficient in vitamines, and, as teeth are composed chiefly of lime, the metabolism of mineral salts is a factor of great importance. In referring to mineral salts I mean their organic combinations in food, not inorganic mineral. The latter is comparatively unimportant and can in no way replace the former.

Most of our common foods are deficient in vitamines and mineral salts. Meat contains practically no lime: 99 per cent. of the lime in an animal is contained in the bones; and carnivorous animals, who depend altogether on animal food, eat the bones as well as the flesh. Wheat, whole rice, maize, and barley are valuable sources of vitamines and salts, but in the artificially refined and partial state in which they are now eaten—as white flour, polished rice, cornflour, and pearl barley—they are deprived of their germ and outer layers, and so lose all their vitamines and about 50 per cent. of their salts. In the common method of boiling vegetables an average of 40 per cent. of their potash and other salts is thrown down the sink. By carelessness in allowing vegetables to cook for an unduly long time, their vitamines are to a great extent destroyed. Sago, tapioca, and arrowroot consist of chemically or mechanically separated starch, and are deficient in vitamines and salts. The vitamines of the fruit in jam are completely devitalised by the prolonged cooking to which they are subjected. The same applies to sugar, which is chemically pure, and therefore a highly deficient and unbalanced food. All the common foods have been mentioned except oatmeal, milk and its products, fruit and honey, all of which are valuable for their vitamines and salts.

It is obvious, therefore, that the bulk of our diet is very deficient in these important constituents. Enough has been said by those who have done original work regarding the effects of deficiency of vitamines to indicate that their artificial removal is a dangerous procedure, and that it is impossible at present to estimate how much ill-health and lowered vitality are directly due to it.

With regard to mineral nutriment, Bunge says that lime and iron salts are those which are likely to be insufficient in ordinary diets. Sherman, of Columbia University, says that the usual diet is frequently deficient in lime. These deficiencies are calculated in terms of the adult requirement of calcium, but the growing child, whose bones and teeth are in process of calcification, requires more calcium in proportion to its weight than the adult. Hence to the child this deficiency is more serious.

The deficiency of lime would be serious enough in itself, but is rendered more so by the concurrent deficiency of other alkaline salts, as will be shown.

As a result of metabolism, acid substances are produced which have to be neutralised in the body. They are neutralised by the alkaline bases derived from food. Hence the great value of the alkaline salts of potassium and sodium, and of the vegetable and fruit acids, which are oxidised into alkaline carbonates.

Meat is relatively poor in basic salts. Meat contains sulphur and phosphorous compounds which by oxidisation in the body form sulphuric and phosphoric acids. According to Sherman, meat and eggs yield a considerable excess of acids. A diet in which the acid-forming elements greatly predominate must result in a withdrawal of fixed alkalies from the blood and tissues.

Now, in cooking vegetables we throw away 40 per cent. of these vegetable alkalies; and in New Zealand we eat an absurd excess of meat. What seems to be a matter of immense importance is this—that, under these circumstances, calcium, which is on its way to the building of bones and teeth, may be diverted into the neutralising of these acids, and in this way the calcification of bones and of dental enamel may be interfered with.

Not only is it possible by the depletion of the alkaline reserves of the body to divert calcium from bone construction, but, according to Voit, bone takes some part in the daily metabolism, and it is possible, on a diet deficient in mineral, for the lime in the bones to be withdrawn to neutralise the acids of metabolism. Bunge says that calcium more than any other inorganic element is likely to be deficient as a result of the change from mother’s milk to other food. It has been shown that the majority of American diets even for the adult are dangerously deficient in lime, and also in phosphorus—and what applies to American applies also to New Zealand diets, for they are practically the same.

It is now definitely established that in anaemia medicinal inorganic iron is not itself built into haemoglobin, but acts only as a stimulant to blood-formation from the organic iron compounds of food. The iron content of food, which according to Abderhalden is also dangerously low in the average diet, is therefore a matter of great importance. Everything points to the necessity of giving serious consideration to the mineral content of our diet, especially as degeneration in the structure and rapid decay of the teeth—one of the chief mineral-built organs in the body—has become such a veritable menace to national health.

I will quote a passage from Von Noorden, one of the strongest advocates of a liberal use of meat in the adult diet. He says: “The necessity of a generous supply of vegetables and fruits must be particularly emphasised. They are of the greatest importance for the normal development of the body and of all its functions. As far as children are concerned, we believe we could do better by following the diet of the most rigid vegetarians than by feeding the children as though they were carnivora, according to the bad custom which is still prevalent. If we limit the most important sources of iron—vegetables and fruits—we cause a certain sluggishness of blood formations and an entire lack of reserve iron such as is normally found in the liver, spleen, and bone marrow of healthy well-nourished individuals.”

In Sherman’s “Chemistry of Food and Nutrition” we find: “In an experimental dietary study in New York it was found that the free use of vegetables, whole wheat bread, and the cheaper sorts of fruit, with milk, but without meat, resulted in a gain of 30 per cent. in the iron content of the diet, while the protein, fuel value, and cost remained the same as in the ordinary mixed diet.” I make these quotations to emphasise the importance of the salts of vegetable foods as constituents of our diet.

The consideration of the causes of dental caries is not complete without reference to the effects of modern diet upon the flow of saliva and upon acid fermentation in the mouth. This subject has been fully dealt with by Dr. Pickerill, and I believe it to be of very great importance. I will confine myself to the observation that the same artificialities in diet which contribute to poorly-built teeth also have a depressing effect upon the flow of saliva. The lack of hard food, the undue moisture and pastiness of food, the lack of fibre, of raw vegetable juices and raw fruit, the excessive consumption of sugar and tea and sweet confectionery—all these factors depress the flow of saliva and contribute to the retention of food about the teeth. The high milling of cereals, the removal of so much mineral matter and flavour from vegetables by cooking, and the use of so many artificially separated and soft foods, not only produce badly­formed teeth and jaws, but also increase the virulence of the conditions they have to contend with in the mouth.

There may be some difference of opinion as to the exact modus operandi of how these defects of childhood are brought about, and I do not wish to insist too much on any particular theory. My main contention is that it is the artificial nature of the foods we eat—something in the food, or something which is not in it—that is responsible for these evidences of malnutrition. No one, I think, will disagree on this point—the fate of the Māori’s teeth in the course of about two generations is a clear proof of it.

I think you will agree with me, however, that we have very definite scientific reasons for urging the most radical dietetic reform. We know that the mineral and vitamine contents of foods are reduced by artificial processes. We know—if we know anything—that these deficiencies cause poor nutrition and poor development of bones and teeth; and at the same time these very defects are assuming gigantic proportions and threatening to undermine our national welfare. If the British Empire is to successfully withstand the storms of the future we must possess that indispensable foundation of national greatness, the health of the people. Food, of all matters, is the basis of health. We must have hard food, that we may learn the salutary virtue of mastication; we must have whole cereals—wheatmeal bread and unpolished rice; we must eat less meat; learn the value of fruits and vegetables, and above all, learn how to cook them; we must appreciate the value of uncooked foods—we must look after the salts and the vitamines. I do not know of any matter of more urgent and vital importance to the health of the country than this one of food.

Now, in this paper I have called your attention to matters which have already been written about by others, but which, from my experience in the medical inspection of school-children, I am very strongly of opinion deserve more serious consideration than they have up to the present received. As Superintendent of the School Medical Services I am concerned with the health of the rising generation. The medical inspectors of schools are apostles of health, endeavouring to educate the public in how to rear healthy, robust, and vigorous children. At the recent conference of our staff in Wellington a committee was formed to decide upon a uniform code of recommendations regarding children’s health, most of which are embodied in what I have already said. If any of our fraternity in private practice have other theories as to the causes of these defects, or can in any way assist us, we shall be very much indebted to them. It is our aim to lay the foundations of a healthier, a happier, and a more prosperous New Zealand; we want your help and co-operation in this great work.

P.S.—As a result of talking over some of these matters at the Medical Conference, I have modified my views slightly regarding the causes of maldevelopment of the jaws. While I still maintain that vigorous mastication has a very important effect upon the size and general growth of the jaws, I believe now that the actual shape of the jaw is controlled more by the moulding action of the lips and tongue. The muscles of mastication are attached to the posterior part of the jaws, whereas it is the anterior part of the alveoler arch which is so commonly narrowed and mis-shaped. I am inclined to think that the first factor in the vicious series is bottle-feeding and the dummy. These tend to push up the centre of the palate and to narrow the jaws by the constant sucking, thus producing the tendency to nasal obstruction. The resulting open mouth brings further narrowing pressure on the jaws, and the open relaxed lips allow the incisor teeth to be pressed forward. These forces, though slight, are acting constantly, and—like the ivy spray which pushes its way through a stone wall—would have a considerable effect upon the soft developing jawbone. Decay and early extraction of the temporary teeth are other important causes of undersized jaws.