Periodontitis is classified by the author among the diseases of the alveolar process. He occupies himself with this affection at great length, seeking to explain the mode in which it is produced. He distinguishes two forms of the disease, according to whether or not there be exit of pus from the alveolus. The alveolar process is, in his opinion, the principal seat of the disease, to which, as a complication, is added the retraction of the gums. For the diseased alveolus the tooth becomes, in a certain manner, an extraneous body, of which it tends to rid itself. The alveolar margins undergo absorption; the bottom of the alveolus tends to fill up, analogously to what occurs after extraction, and the falling out of the tooth ensues as a natural consequence of this process. An altogether similar process, producing the falling out of the teeth, is the normal consequence of senility. The author considers that the malady in question has as its point of departure an irritation caused by a tooth; and as almost a proof of this he relates a case in which the extraction of the affected tooth, an upper incisor which became too long, and the transplantation of another tooth caused the cessation of the morbid process and the perfect consolidation of the transplanted tooth. However, Hunter does not draw from this isolated case the conclusion that transplantation may be elevated to a method of cure for this malady. Indeed, he says that, so far as is known to him, there is no means of prevention or of cure for it. His treatment, therefore, is merely directed to the curing, in so far as is possible, the phlogistic symptoms, by scarifications of the gum and by the use of astringent remedies. He does not exclude the possibility of a complete recovery, but the mode in which this obtains seems to him as obscure as is the nature of the disease itself. In speaking of the correction of dental irregularities, Hunter advises not to extract the milk teeth unless this be an absolute necessity. He says, besides, that it is useless to extract any tooth whatever, unless one endeavors at the same time to force the irregular tooth or teeth into their normal position by exercising the requisite pressure upon them. In young subjects the regulating of crooked teeth is an easy matter, because of the softness of the maxillary bone. However, it should not be undertaken before all the bicuspids have come through. To correct protrusion of the upper jaw, the author recommends the extraction of a bicuspid on each side. To regulate the incisors it is sometimes necessary to make them rotate on their axis with the forceps. In certain cases of protrusion of the lower jaw one may have recourse with advantage to the inclined plane. As a general rule, it is useless to lay bare a tooth with the lancet before extracting it, although in certain cases this may be advantageous in order to render its extraction easier and less painful.