Caries, says Hunter, is a disease of altogether obscure origin; it is not owing to external irritation or to chemical processes, and seems to be a morbid form altogether peculiar to the teeth. Only in very rare cases does it attack the roots of the teeth. It rarely appears after fifty years of age. Hunter does not admit that this disease may be communicated by one tooth to another. As to its treatment, the caries, if superficial, may be completely removed by filing the decayed part of the tooth before the disease penetrates to the cavity, and its spreading will thus be arrested for a time at least. In cases where the caries penetrates to some depth, without, however, the destruction of the crown of the tooth being so extensive as to render it useless, Hunter believed the best mode of treatment to be extraction and replanting of the tooth after having subjected it to boiling in order to cleanse it perfectly and to destroy its vitality entirely, this being, according to him, the mode of preventing the further destruction of the tooth, which once dead can no longer be the seat of any disease. If, instead, one wishes to have recourse to cauterization of the nerve, it is necessary to reach as far as the apex of the root; which, however, is not always possible. This is a very important point, for no one before Hunter had yet affirmed the necessity of entirely destroying the diseased pulp as an indispensable condition of the success of the filling to be later carried out in order to conserve the tooth. Hunter is extremely concise when speaking of the filling of teeth; considering the great importance of this argument, his conciseness can only depend on his having had no personal experience in the matter. He considers lead preferable for fillings. The frequent occurrence of erosion of the teeth, whether of the cuneiform variety or of other kinds, did not escape the attention of this acute observer, but he was not able to give any explanation of it. In cases of empyema of Highmore’s antrum, Hunter advises the opening of the cavity through the alveolus of the first or second large molar.