302 APPENDIX. 



In dissolving the lime-salts on the surface of the enamel (or in 

 any depression or irregular surface of a tooth where food lodges until 

 decomposition occurs), the living matter in that tissue becomes ex- 

 posed, and at once, under the effect of the acid, becomes more or 

 less irritated. This irritation extends into the substance of the 

 enamel beyond the point at which absolute destruction of the tissue 

 has taken place, which fact may readily be determined by diligent 

 examination of specimens of carious enamel carefully prepared. Un- 

 der this irritation, constantly applied, inflammation soon follows; 

 this causes more or less of a swelling of the living matter, which 

 effects the dislodgment of the lime-salts a melting down of the 

 glue-giving basis-substance, and a bringing to view, under a power 

 of from 1,000 to 1,500 diameters, the medullary or embryonal ele- 

 ments of the enamel. As the caries reaches the dentine, the same 

 inflammatory reaction, with the swelling of the living matter, the 

 enlargement of the canaliculi, dislodgment of the lime-salts, and 

 melting down of the glue-giving basis-substance, becomes more in- 

 tense, just in proportion as there is more organic and living matter 

 in the dentine than in the enamel. These lime- salts are not neces- 

 sarily dissolved and taken away, but may, and I have no doubt, as 

 Prof. Mayr's experiments show, do remain mixed with this disor- 

 ganized tooth-substance. 



On examination of a specimen of acute caries, cross-section, at a 

 considerable distance from the disintegrated granular mass (always 

 to be found upon the surface of caries), may be seen enlarged cana- 

 liculi, some double, some treble, some four, six, eight, yes, even fifty 

 times as large as normal. In many instances, near the surface, as 

 many as six or eight may be seen to have joined together. The 

 lime-salts between and around the canaliculi having been dislodged, 

 the glue-giving basis- substance melted down, and forming partly 

 nodulated protoplasmic bodies, in which the living matter is brought 

 to view, in the shape of nuclei, with occasional threads running from 

 one protoplasmic body to another. It is ihis living matter so brought 

 to view, which in my judgment has been mistaken by some ob- 

 servers for organisms. Many such enlarged canaliculi remain in a 

 tooth after the supposed carious portion has been removed and the 

 tooth filled. In such cases the acid irritant formerly in the cavity 

 is removed, the inflammatory condition subsides, and the lime-salts 

 become re-deposited. In other words, these deep-seated lesions 

 heal and become as solid and to all appearances as healthy tooth- 

 bone as ever. Could this occur if these enlarged canaliculi were 



