„***• 



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Fig. 1. Unbrushed masticatory mucosa of Merion rat No. A 3. Scale in p.. 

 Reproduced by permission of Brit. dent. J. 



H 



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Fig. 2. Masticatory mucosa from opposite maxilla of same rat after 1 month's 

 brushing. Scale in \x. 



Reproduced by permission of Brit. dent. ./. 



[facing page 52 



