In the Philadelphia republication of Dr. Underwood's book, taken from the sixth London edition, there is an article entitled Cancrum Oris. The author appears to have read Pearson's account; but as his description does not at all agree with the disease of which we are treating, nor with that of Mr. Pearson, we shall not stop longer to analyse it.

I have no doubt, from views that will be hereafter developed, that many of the above writers have had cases similar to those which we are about to describe; but have mistaken them, from the want of a sufficiently early and close inspection of the ulcers. In the second stage, this disease much resembles an inflamed sore between the lips and gums, extending to the latter; although I hope to prove that this state of things is secondary.

Locality of the Disease.—The Philadelphia Children's Asylum is situated in South Fifth street, between Prime and Federal streets, in the district of Southwark. The soil is what is called alluvial, or rather diluvial; as is well known to be the case with all that district, lying south of Philadelphia, as well as the southern part of the city itself. The house was built, and for many years occupied, as a mansion, by the head of a most respectable and wealthy family. Its situation possesses some of the qualities usually selected in choosing the site of a country seat. The buildings stand on a swell of ground, leaving an open lawn, now interrupted by several unoccupied streets, and extending, on the right hand, to the banks of the Delaware, and, on the left, to the Navy Yard and part of the suburb of Southwark. Towards the north, it is not far from the edge of a thickly built appendage of the city.

The district immediately south of the Asylum is marshy, and has long been noted for the prevalence of intermittent fevers; but the slightly elevated site of the building had been generally healthy, and continued so, till the universal and distressing epidemic, which infested all the outskirts of Philadelphia, in 1822 and 1823. Even at this period, the persons resident at the Asylum, were far from suffering so severely as the adjacent neighbourhood; and, since those years, it has again become, in general, tolerably healthy. In 1819, 1820, 1821, and 1822, a lot, situated at a short distance, on which were deposited the contents of a number of privies, proved a source of great inconvenience, and some disease, at the Asylum. This focus of effluvia, together with the general and copious use of similar materials in manuring the adjacent fields, occasioned an intolerable stench, and generated diarrhœas, in the early part of the spring. When the grass and weeds, however, were grown sufficiently to protect the surface of the soil from the sun and wind, this effect entirely ceased; and I know not that any other inconvenience was experienced from the same source, unless we attribute to this, as may fairly be done, the destruction of the purity of the well. This formerly afforded very good water; and, since that period, it has much improved. When the corporations of Southwark and Moyamensing shall introduce, as it is to be hoped they will, the Fairmount water into their streets, one remaining cause of inconvenience and ill health, will be removed from the Children's Asylum.

Prevalent Diseases.—Ophthalmias and furuncular eruptions, the latter principally on the face, are epidemic every year; generally in the spring and early summer months. When prevalent in the city, the measles, small pox, and varioloid disease have reached the Asylum; the scarlatina has, at no period, I believe, been peculiarly troublesome there. Intermittents, which were anticipated by many, from the nature of the situation, have seldom, if ever, prevailed in the house, to any very considerable extent. One of the worst visitations which it has experienced, in this respect, was in the autumn of 1823. In many cases, it was in patients who had been labouring under disease of this description, that the ulcer we are about to describe exhibited itself; but it was by no means confined to those who were known to have so suffered. Many, perhaps, most of the children affected, were free from any apparent ailment; although it is by no means impossible that the little, uncomplaining subjects were, at the time, labouring under what has been called "febricula" or "inward fever."

Regimen.—To the impurity of the water we have already adverted. The diet of the children furnishes them with meat every day, with the exception, during a part of the existence of the institution, of two days in every week. Molasses was freely used; indian mush was greatly in demand; and the breakfast and supper were of bread and milk. During the summer months, this diet was abundantly nourishing; but in winter, it was thought that an additional quantity of animal food was desirable; and, accordingly, it was, during the two last winters, given every day.

Description of the Disease.—The ulcer of which we speak, may begin in many parts of the mouth. In by far the greater number of cases, however, it commences immediately at the edges of the gums, in contact with the necks of the teeth, and, most generally, of the two lower incisors. A separation is found here; which exhibits a slight loss of substance at the extreme edge of the gums, and, as far as I have observed, a whitishness of the diseased surface. In some instances, though not very frequently, this is preceded by a slight swelling and redness. In this state, the disease may continue for a long time; and I have reason to believe, that patients have remained thus affected, during the whole period of three months, for which I attended the Asylum. At one time, when the disease was at its height, threatening several patients with destruction, I found upwards of 70 children, out of a population amounting to about 240, more or less affected with these ulcerations. No remarkable change is at this stage observable in the functions of the little sufferer; except a general air of languor and weakness. The appetite and the muscular activity continue, but are somewhat reduced; not sufficiently, however, to disable the child from attending school, taking the air, or continuing his ordinary practices. In this state, no symptoms of irritation have been at all discovered. The skin is cool during the day, no pain is complained of; and no account has ever been given me of any nocturnal paroxysm of fever. It would appear to be purely a state of asthenia. We are, however, by no means certain, that there was no concealed irritation in the system. We were, of necessity, obliged to depend, in a great measure, upon the reports of nurses, and other females; and these were liable to overlook, or mistake for mere weakness, the signs of an obscure disease. In this manner, commencing cases were frequently not discovered, and nothing was done, till the affection had made further progress; and this continued until the ascertained existence of the epidemic in the house, combined with the recollection of its former ravages, had excited an alarm, which led to the inspection of the mouths of all the children in the institution.

The disease, in this form, must be within the curative powers of nature; as, if this were not the case, we should hear of more numerous unfavourable terminations. It has seldom, however, if at all, been within my power to witness this tendency; and, when not controlled by a particular treatment, the cases have almost always either remained stationary, or increased in severity. Its first progress is, most generally, by extending to the edges of the gums round other teeth; frequently affecting a large portion of the dental arches. A very early progress is, however, mostly effected, down the length of the tooth, in the direction of the socket; and, in this way, the disease commits great and unsuspected ravages. When it reaches the edges of the bony socket, the tooth begins to be loose, and when drawn, exhibits portions of the fang, including parts which had been contained within the alveolus, entirely denuded of their periosteum. Indeed, from observation, I should say, that the latter membrane was the part, which was the most peculiarly liable to injury and death from this disease; and it is by no means clear, to my apprehension, that this is not frequently the commencement of the complaint. The injury generally proceeds with augmenting rapidity; especially when it has affected the deeper parts: and it is while in the act of rapidly spreading, that it occasions gangrene.

In the production of gangrenous sloughs, it much resembles the descriptions usually given of sloughing ulcers. A portion of the parts immediately subjacent to the ulcer loses its life; this rapidly separates; and, before or after a complete removal, a fresh slough is formed in the same manner. The sloughs are generally black, with ash-coloured edges. I have not been able to discern a change of colour, the production of vesicles, or any material tumefaction, as antecedent to the gangrene. There is generally, by this time, an increased heat in the parts; with the sensation termed "calor mordens." The discharge now, for the first time, becomes acrimonious; giving pain when it comes in contact with cuts in the finger; and excoriations are produced on all parts in contact with the sloughing ulcerations; as the lips, the cheeks, the tongue, and the adjoining surface of the part where the ulcer is situated.

As soon as the external gangrene has reached the level of the edge of the bony socket, and frequently much sooner, the adjacent portion of the latter is found deprived of its life; forming a necrosis. The death of the periosteum in the socket, at least that of the fang of the tooth, precedes, by some interval of time, that of any portion of the bone itself.