One of the pleasures of travelling in America is the sight of any number of fine, regular, clean teeth in the mouths of people. The contrast with our own country is notorious and has often been commented upon. Of course there are carious teeth in America and there are many dentists- none without a qualification being allowed to practice; but, in general, teeth are health and pleasant to look upon. In the past six weeks I have encountered only one mouthful of carious and neglected teeth, and one malodorous breath-and that, I regret to say, was in Canada, in the mouth of a public man who, not un-naturally, was excusing himself from making a speech because his throat was giving him trouble.

At a recent Conference in Manchester, which I was fortunate to attend, the following summary of our English dentition was read by Dr. Harry Campbell, the editor of the Medical Press and Circular, and an acknowledged authority of dietetics:

We have the worst teeth of any nation. The state of our teeth beggars description. It is a national disgrace which should excite a feeling of shame and humiliation.

Diseases of the teeth include:
(1) Irregularities.
(2) Loss from extracting and shedding.
(3) Decay.
(4) Disease at the fang-tips.
(5) Pyorrhoea, or socket disease.

Regarding the extent of these amongst the British, dental irregularities are practically universal among us. Some hundred million teeth have been extracted. About the same number have been spontaneously shed. The decayed teeth number some two hundred million; there are about the same number of pyorrhoea sockets; finally there are some twenty million diseased fang tips. At least nine-tenths of this disease is preventable.

The consequences of dental disease are:
(1) Malodorous breath.
(2) Unsightliness (from irregularities, decay, long teeth).
(3) Pain (toothache, pain inflicted by dentist, fear of dentist).
(4) Reflex disturbances.
(5) Defective mastication (causing indigestion).
(6) Secondary local disease (abscess and cancer).
(7) Blood poisoning (arthritis, neuritis).
(8) Economic Loss (loss of time; need of supplying army dental surgeons).

Ignoring the teeth of the American Negro (which I do not observe nowadays markedly if at all better, though certainly larger, than those of the white man), and also ignoring the teeth of the Jews, which are notably superior everywhere-compare Whitechapel and Southwark for instance-there can be no doubt whatever that an extreme and deplorable contrast exists between the teeth of the individuals of the same races on the two sides of the Atlantic. It ought not to be very difficult, surely, to find the reasons, and there discovery should be very useful for us.

Heredity and the suspended operation of natural selection we may rule out. I am comparing persons unmistakenly English or Scottish in stock. As for the theory that our bad teeth are due to modern conditions (dentistry, cooking, etc.), which allow people with inferior teeth to survive and beget their like, it is invalidated by the Atlantic contrast here under discussion.

In our own country two distinct theories of dental caries have been advanced. They are by no means incompatible- unless either should be stated as the whole of the truth. Both refer to our national diet as the cause, but entirely different ways.

The newer of the two has been mentioned here on the course of our discussion of vitamins. (This word we used to spell vitamines, but since the namer was wrong in naming to be amines, and in coining there name accordingly, we do better to drop the terminal- e and thus avoid a misleading chemical suggestion.) The work of Mrs. Mellanby, under the auspices of the Medical Research Council, has shown that the proper eruption and spacing of the teeth in the jaws of puppies, and the subsequent deposit of enamel upon them, are dependent upon an adequate and continuous supply of vitamin A, the "anti- rhachitic factor," in their diet. The rule almost appears to be that the nothing makes hard teeth like soft butter- though perhaps crude cod-liver oil would be better still. I have seen the jaws of many of Mrs. Mellanby's experimental puppies, and they are very striking.

There is no doubt that regularly spaced teeth, with proper contact-points preventing the food from stopping between them and damaging the interdental papillae of gum-tissue, are less likely to decay; but, apart from that, the views of our most expert and scientific dental surgeons do not appear to be favourable to Mrs, Mellanby's conclusion that caries of teeth is essentially a phenomenon comparable with rickets of the bones, and is due to the same cause. Clearly the production of enamel is one thing and the protection of enamel is another, and the dentists' view is that, somehow or the other, even though enamel may be properly produced in the first place, we fail to protect it from the active agents-acids produced by bacteria-of its destruction.

Thus, our dentists, represented especially by Dr. Sim Wallace, who has been writing most interesting monographs on this subject for many years, take the view that our national diet is to blame, not in that it fails to contain enough vitamin A in our early years- or up to eighteen, when the formation of enamel ceases-but because of its physical condition, which fails to exercise the teeth, and tends to leave fermentable material between them after our meals. According to this teaching, the toothbrush is seriously discredited. We may continue to use it, in order to make our teeth look clean, we are told, but that is all we can expect of it. Dr. Harry Campbell, and Dr. James Wheatly, Medical Officer of Health of Shropshire, who has lately done wonders in reducing dental disease among school children by education in his county, are in agreement with Dr. Sim Wallace when he teaches as follows:

Dental caries can only be prevented by physiological means. These are:
(1)Mechanical (the motions of the jaws, tongue, lips, and cheek) and the action of foods with certain physical qualities, e.g., fibrillar or spongy foods.
(2)Chemico-physiological, resulting from the activities of the glands of oral hygiene (mucous and salivary).

When the physiological activity of the muscles of mastication, tongue, etc., and the physiological activity of the glands of oral hygiene are not interfered with or stultified by unphysiological foods, especially at the end of or between meals, dental caries does not occur.

The toothbrush, and the American invention of dental silk, used for the same purpose as the toothpick, are not here mentioned. But we are told to eat hard foods, which exercise the teeth, to avoid "mush" and "pap,"and to end the meal with fruit, such as apples, which leave the mouth clean. Nothing could be more reasonable and natural than this teaching, which is based upon the fundamental law of life, that what is not used declines, decays, disappears and dies.

With these theories and observations in my head I have carefully observing the American dietary, during the last few weeks, in order to see whether the Mellanby or the Sim Wallace theory finds the clearer confirmation. So far as the latter is concerned, I am convinced that, though it cannot but be sound itself, it finds no support whatsoever in American practice. These fine teeth I see all around me here are certainly not the result of the protection afforded by the kind of dietary recommended by Dr. Sim Wallace and others in our country. The American does not exercise his teeth one whit more than we do. He is very partial to "mush" and "pap," in the form of his breakfast foods. He is very fond of fruit, but he eats it not at the end of his meals, as Dr. Sim Wallace desires, but at the beginning. However he manages to protect his teeth, it is certainly not by physiological means which our best students recommend. His diet, in respect of the demands it makes upon his teeth, is as entirely unphysiological as ours.

On the other hand, the diet of the American child is potently anti-rachitic, most abundant in milk and cream and butter, so that, with a few exceptions which prove the rule, rickets is unknown-in three prolonged visits I have not yet seen a rachitic child-and therefore the eruption, spacing and enamel-formation of American teeth should be well nigh perfect, on Mrs. Mellanby's theory, and indeed are so.

Nevertheless, I do not for a moment believe that her theory wholly accounts for the facts. The high degree of protection somehow afforded to these well produced teeth must be accounted for, and we have seen that the adult dietary does not do so. In the course of many hours in the dental chair in Chicago, where I was the subject of masterly work upon six necessitous teeth, after being told that my mouth was in good order just before I left London, I learnt that great care is taken of the teeth of school children, which must be compulsorily treated when necessary; and, further, that American dentists do believe in the toothbrush, when properly used, for more than cosmetic purposes, and also in dental silk. The average American takes much better care of his teeth, and is the subject of vastly superior dentistry. He is taught far mire respect for his mouth and teeth, and treats them accordingly.

We need everywhere a better dietary for our children; such teaching as Dr. Wheatly has instituted for those under his care; and far more qualified dentists and far fewer of the other kind, who recommended to their patients the blessings of artificial teeth which cannot ache or decay. The remedies are partly personal and partly social. Who ever heard in England, for instance, of a pre- school dental clinic, such as I was told about in Toronto the other day? We need a far higher standard of personal pride in our general and local cleanliness and appearance, and we need a campaign in the lines of Dr. Harry Campbell's dreadful diatribe to arouse is to the shameful character of our national dentition, its deplorable consequences, and its preventable character.