I shall, in conclusion, briefly recapitulate the advantages of this mode of treatment. In the first place, it will be found far more efficacious and speedy than any other; secondly, it has the great advantage of saving the patient much suffering and inconvenience; and thirdly, it renders the repeated application of dressings and ointments quite unnecessary. Its utility is extremely great, therefore, where the time of the poor, the expense of an establishment, and the labours of the medical officer, as well as the sufferings of the patient, require to be considered; and it will I imagine be found of no little advantage, in all these respects, in many cases which are incident to the soldier and sailor.
The eschar is generally adherent in cases of recent injuries, and in small ulcers, when they are nearly even with the skin and attended by little inflammation. In other cases the eschar is too apt to be unadherent, and this arises from the formation of pus or of a scab underneath.
If the eschar be unadherent by subjacent pus, it may be ascertained in the space of from twelve to twenty-four hours; the centre is generally observed to be raised and to yield to the pressure of a probe; sometimes the subjacent fluid has partly escaped by an opening at the side of the eschar.
When a scab forms underneath the eschar, which does not happen except the fluid has been allowed to remain too long under the eschar without being evacuated, there are pain and some inflammation, the eschar does not separate, but remains long over the sore, and there is no appearance of healing.
When it is ascertained that there is fluid underneath the eschar, a slight puncture is to be made by the point of a penknife, the fluid is to be gently pressed out, and the caustic is then to be applied to the orifice thus made. The same plan is to be adopted if the fluid ooze out at the edge of the eschar; it is to be fully evacuated by pressure, and the orifice is to be touched with the caustic. The healing process goes on best however when the orifice is in the centre of the eschar. After this treatment the eschar occasionally remains adherent, but more frequently the fluid requires to be evacuated repeatedly, and this should be done every twelve hours, or once a day, according to the quantity of fluid formed, taking care that the eschar be not needlessly separated by allowing the fluid to accumulate underneath. If, from accident, the eschar is separated before the sore be healed I would reapply the caustic. At length the eschar becomes adherent, and in due time begins to peel off, leaving the surface healed.