SECTIONAL TRANSACTIONS.— I. 375 



(1) The study of the conditions which result in perfectly calcified teeth regularly 

 arranged in well -developed jaws. 



(2) Methods for increasing the resistance of the living teeth to harmful influences, 

 sucti as attrition and caries, after eruption. 



The careful examination, both macroscopical and microscopical, of large numbers 

 of teeth, especially of deciduous teeth of children, has demonstrated a definite 

 relationship between the structure — the calcification — of teeth and their liability 

 to decay; the worse the structure the greater the susceptibility. Now these 

 investigations have shown that the majority of children in the British Isles (and 

 probably in other countries also, although much less material is at present available 

 for investigation in the latter) possess poorly calcified teeth. About 80 per cent, 

 of the deciduous teeth, not 2 to 3 per cent, as has been usually stated, were found to 

 be defective or hypoplastic in structure. The incisors were much better calcified 

 and less susceptible to caries than the molars. It is, therefore, obviously important 

 to ensure good calcification of the developing teeth. In puppies and other animals 

 perfect and imperfect teeth can be produced at will by slight variations in the diet, 

 and as far as our present limited knowledge goes, these same variations in diet affect 

 the structure of children's teeth also. 



The two main factors influencing dental structure have been shown to be 

 VitaminD which aids calcification, and some substance in cereals which interferes with 

 this process. The effect of ultra-violet radiations, also conducive to good dentition, is 

 now known to be due to the production in the tissues of Vitamin D from its precursor 

 ergosterol. A minimum of calcium and phosphorus is, of course, essential, but this 

 minimum varies with the amount of Vitamin D in the diet, and cannot be stated as 

 an absolute quantity. Neither Vitamin C nor Vitamins Bj and B.> have any specific 

 effect upon the calcification of teeth in puppies. 



Although there is a definite relationship between structure and caries, teeth perfect 

 in structure sometimes become carious, whereas defectively calcified teeth may 

 remain free from the disease. It has been shown experimentally that the resistance 

 of teeth to external harmful stimuli can be controlled by diet independently of 

 the original structure and that some of the same factors of diet which influence the 

 development of teeth also affect tbeir resistance. 



Controlled investigations on children, based on the experimental work on animals 

 already mentioned, show that the initiation and spread of dental caries can be 

 greatly reduced by increasing the intake of vitamin D and reducing that of cereals, 

 and especially of oatmeal. 



Calcification of the deciduous teeth starts while the infant is inutero; it is there- 

 fore essential that the mother during pregnancy and lactation should have a sufficient 

 supply of the substances necessary for good calcification, partly to ensure an adequate 

 supply of these substances to the child, and partly that she herself may not go short 

 of them in releasing her own supplies to the developing embryo, and thus become 

 more liable to dental decay. 



The English diet, especiallj' that of the poorer classes, undoubtedly contains a 

 deficiency of fat-soluble vitamins which are associated with the more expensive foods 

 such as eggs, milk and butter, whereas cereals, which interfere with calcification 

 processes, form the bulk of the diet, for they are comparatively cheap and easily 

 transported. The decrease in breast-feeding and the consequent rearing of infants 

 on cereal concoctions must also tend to result in defectively calcified teeth. 



Although much remains to be learnt as to the aetiology of dental caries, there 

 seems to be little doubt that if more vitamin D and less cereals were included in our 

 diet the structure of our teeth would be very much improved and their susceptibifity 

 to caries would be greatly diminished. 



Dr. S. MoNCKTON CoPEMAN, F.R.S. — Cancer and Diet. 



When the location of the disease is not such as to prevent the taking of sufiicient 

 nutriment it has been found possible, by the adoption of certain dietetic measures, 

 to secure, in many instances, definite prolongation of life as judged by observation 

 of many similar cases, together with such comparative, or even complete, alleviation 

 of pain as alone could render any such extension of fife worth while. 



The dietary in question was first suggested at the Cambridge Meeting of the 

 British Medical Association in 1920, and was the subject of a paper at the Liverpool 

 Meeting of the British Association in 1923. Since then it has been tested in a con- 

 siderable number of cases in various infirmaries and elsewhere ; while in order to 



