300 APPENQTX. 



bacteria was apparent, but as soon as all matter on the surface of 

 the pieces and at the exposed ends of the dentinal fibrils was con- 

 sumed, the number diminished, and at the end of the fourth month 

 only now and then a micrococcus was to be seen. A cloudiness of 

 the liquid did not occur, an acid reaction could not be detected, nor 

 were the pieces of dentine changed, either microscopically or mac- 

 roscopically " (the naked eye). 



These experiments were repeated by Dr. Miller with the addition 

 of a greater quantity of decaying dentine, and the result was the 

 same not a bacteria to be found in or upon the pieces of dentine at 

 the end of four months. In the u general results " which he has 

 arrived at, he says: u The invasion of the fungi is always preceded 

 by the extraction of the lime-salts. The fungi have not the power 

 either to penetrate or to decalcify sound dentine." 



This is the same position taken by myself in the paper I read be- 

 fore the New York Odontological Society in 1879, namely: u The 

 indifferent elements originating through the carious process from 

 enamel, dentine, and cement, do not proceed in new formation of 

 . living matter, but become disintegrated and transformed into a mass 

 crowded with micrococci and leptothrix. Micrococci and leptothrix 

 by no means produce caries ; they do not penetrate the cavities in 

 the basis-substance of the tissues of the tooth, but appear only as sec- 

 ondary formations, owing to the decay of the medullary elements." 



If these experiments have been performed in the careful manner 

 described by Dr. Miller (and I hardly think any one will question 

 it), and such conclusions arrived at, it would certainly seem that we 

 must look for some element aside from micro-organisms for the de- 

 struction of teeth by the carious process. 



I will now present another side of the question. Prof. Charles 

 Mayr, A. M., detailing some chemical experiments which he made 

 for the purpose of establishing the theory that the carious process 

 in human teeth is the dissolving of the tooth structure by an acid or 

 acids, or otherwise, says : " No acids or soluble lime-salts are in the 

 innermost decaj^ed mass; hence no acetic, tartaric, or lactic acid 

 had dissolved much of the lime-salts, because the acetates, lactates, 

 &c.. would not have been washed out completely from the decayed 

 mass; but a small amount would still remain, which, being soluble, 

 would be easily shown by oxalate of ammonia acid. One large de- 

 cay was sliced up into several parts and the slices analyzed. First 

 slice Outermost, very gelatinous, soft layer. Water, 58 per cent, 

 organic, 26 percent, lime-salts, 1G percent; or, omitting the water, 



