72 Discission 



overcome the difficulty. Already in the human subject, entirely apart 

 from ageing, we have got some rather spectacular cures. 



Tunbridge: It is an interesting sideline, that keratinization gives 

 protection against infection. 



Franklin: In some of these people, even with one month's brushing, 

 the infection clears up. 



Gillman: I don't think that the occurrence of keratinization can 

 always be related to the degree of resistance to infection. For example, 

 in vitamin A deficiency and also in pellagra, excessive keratinization is 

 associated with increased susceptibility to infection. On the other hand, 

 keratinization, or its equivalent, in the vagina seems to provide resistance 

 to infections. 



Franklin: I can only say that those are two clashing facts which we 

 will attempt to elucidate later. In any case, the main object, to my mind, 

 is not to help the dental work but to find something that changes with 

 age and so far, to a slight degree, the effects of this brushing have changed 

 with age. 



Lorge: The obviously very limited data we have on the human are 

 extraordinarily interesting. I should like to raise one minor question 

 which again relates to American dental experiences: that is that the 

 amount of pressure or amount of weight that is given to the brush stroke 

 by a youngster as opposed to an adult may be significant. Another point 

 is: what kind of brush stroke produces what kind of effect? It may be 

 interesting to see whether one can measure the amount of weight or 

 pressure exerted against the gums by people of different ages, just to 

 see how much it is. It would be interesting to correlate, for instance, the 

 strength of grip with the result. If you were able to correlate dynamo- 

 meter strength with your results, you may have some additional evidence. 



Tunbridge: I feel from experience of trying to teach patients to do 

 things that the degree of error in any technique so taught is enormous. 

 However capable one may be as an instructor — and obv'ously the more 

 effective your personality the greater the degree of initial success — only 

 some 15 per cent will continue to do as you have asked them if the pro- 

 cess is to be continued for a long time. Might it not be better to choose 

 three age groups? One might take a residential school for children, 

 a prison for your middle aged group, and an Old People's Home. If 

 you were to take twenty people in each of these groups and to use a 

 dynamometer brush you might be able to standardize the technique and, 

 insofar as the samples are fair representations, obtain a quicker answer to 

 your problem than with the present methods. 



Lorge: When we talked of going into World War II, the United States 

 War Department asked me to standardize an intelligence test. When I 

 proposed to use prison populations, the study was rejected on the grounds 

 of "What will the mothers of our soldiers say when they realize that the 

 tests that we used and the results and the findings come from prisons, 

 and not from normal adults!" 



Bourne: In this country, if you use public schools and prisons, you 

 get comparable diets, of course! 



Franklin: Is this inside information? 



