24 OCTOBER 1947, Page 16

Sm,—Janus attributes the good teeth of the Lewis islanders to

the chewing of hard mutton- bones. Are not the teeth of the inhabitants of the Aran Isles and Tristan da Cunha nearly perfect on the entirely soft diet of fish and potatoes ? And is there not a region in America where teeth are good and the soil is rich in fluorine ? Is there anything in the " hard-chewing " theory, or should we concentrate on finding the right diet ? If this question can be answered, it should be.—Yours