Carious enamel has not yet been examined so far through the electron microscope.That is, there are found a few electron microscopic investigations of carious enamel carried out by the following reporters MATSUMIYA, TAKUMA and TSUCHIKURA , SCOTT and ALBRIGHT , AWAZAWA  and ENOKI . SCOTT, et al. examined carious enamel cut into ultra-thin sections, while MATSUMIYA et al., AWAZAWA, and ENOKI observed carious enamel by means of two-step replica method. MATSUMIYA et al. and ENOKI, however, explored natural surfaces of carious enamel. On the other hand, AWAZAWA attempted to elucidate the development behavior of initial dental caries on slightly ground enamel surfaces. For the examination of carious enamel of initial degree, the present author feels that it is of the utmost significance to carry out our researches on undemineralized carious enamel for the purpose of elucidating behavior of calcified enamel tissue against caries, as the enamel highly contains inorganic components. In this study, the author attempted to examine ultra-fine carious images on undemineralized enamel by means of replica method. As the result of this investigation, significant points can be recognized again in the images which are of much interest in cariology. The electron microscopic images of carious enamel are given below accompanied with their explanations.
A great majority of phenol preparations for dental use are found to possess inhibitory effects on the natural healing of the wounds artificially inflicted on the back of experimental rabbits. Of them, phenol-camphor and tincture of iodine have no appreciable healing effects. Absolute alcohol and 2 % hydrogen peroxide have no effects altogether, and only penicillin ointment has been found to possess beneficial effects to a certain degree