_The teeth._--But few cases occurred during the second dentition; and it is doubtful whether any one took place during the first. It should be remarked, however, that children under 2 years, were not admitted to the institution, unless by deception on the part of the parents. No child ever lost a tooth of the second set; and, indeed, the second dentition seemed often to cure the complaint. The greater number of cases occurred between 2 and 5 years of age, but some as late as 8 or 10. In several instances, the ulcer destroyed a portion of the enamel capsule; and the teeth were then cut, with _very perfect enamel_ upon the lower part, while the bone was entirely bare at the ulcerated portion of the capsule. This singular fact proves that no inflammation of the capsule, sufficient to interrupt the function of its remaining portion, took place in consequence of the opening of its cavity. _Prevalence of this disease in our own country._--Many elderly persons remember during different periods of their lives, a tradition and particular instances of a formidable disease of the mouth, by the name of "Black Canker."[10] Round Philadelphia, it appears to have been rare. Having been informed by a friend, that the disease had prevailed extensively at Salem, New Jersey, under the notice of my friend, Dr. THEOPHILUS R. BEESLEY, I addressed a letter to that gentleman, to which he furnished me with an obliging and instructive reply, which I have unfortunately mislaid. Numerous cases have occurred, in that vicinity, within the last 30 years; and were, in general, successfully treated by the women. Cases seldom came under the view of physicians, until gangrene had commenced; and of these, many died: so that the old women were generally more in vogue for its cure, than the regular practitioners. Dr. BEESLEY, Dr. VANMETER, and my friend Dr. E. Q. KEASBEY, had met with much of this complaint; and the result of many of their observations had been combined in a thesis, written, but, according to our unfortunate custom, not published, by the younger Dr. VANMETER. It was there considered as a sequela of intermittent and slow remittent fevers, and seldom occurred but in marshy districts, and among the poor. It generally prevailed between the ages of 2 and 10 years. Of the remedies employed we shall again speak. Dr. SAMUEL TUCKER has also seen it in marshy situations near Burlington. I have heard of its existence on the Schuylkill. Dr. PARRISH has for several years noticed a stage of this complaint, under the name of "a disease resembling the effects of mercury," in his private lectures. Drs. PHYSICK, HARTSHORNE, HEWSON, MEIGS, WOOD, RHEA BARTON, and REMINGTON, and several others who will pardon me for omitting their names, have also met with cases.