The Interpretation of Dental Lesions in the Light of Recent Research

In attempting to assess the value of scientific work, carried out many years ago, and to compare this with recent investigation, it is at once evident that recent investigation has distinct advantages arising from the development of modern scientific methods. It is to the credit of the men of Miller's time that they were able to do so much with the limited facilities then at hand, and that their theories should have stood until to-day. The recent isolation, by means of modem bacteriological methods, of microorganisms associated with dental caries, such as B. acidophilus by James McIntosh, Warwick James, and Lazarus-Barlow; lactic acid bacilli by Captain Rodriguez, and Streptococcus mutans by Clarke, tends to support the work of Miller that was carried out under the disadvantages of his time. In 1917, our laboratory published an account of microorganisms isolated from dental caries, among which were bacteria similar to those described by the above authorities. We later brought out other micro6rganisms, using enrichment media and various modes of cultivation. We have not, however, succeeded in producing caries in living animals with any of these microorganisms. McIntosh, James, and LazarusBarlow also report the futility of their efforts to produce caries in rabbits or monkeys with B. acidophilus, with the possible exception