DENTAL CARIES IN THE COTTON EAT(22)

ted easy penetration by a no. 42 fine wire dental probe.cording to these findings, the natural diet containing processedcereals used in these experiments should have been less cario-genic than the synthetic diet. Both diets contained 67% carbohydrate but in the synthetic diet all the carbohydrate waspresent as sucrose, whereas in the natural diet only 30% wassugar (18% sucrose, 12% lactose). However, in the courseof investigating the role of nutrition in caries production incotton rats in this laboratory, Zepplin et al. ( '50) observedthat natural diets containing 17% sucrose were more cario-genic than a synthetic diet containing 67% sucrose. The nat-ural diets used by Zepplin et al. resembled the average humandietary as closely as possible within the limitations imposedby the use of exper