vations evidently shew, that such accidents arise merely from the incisions, and the treatment of them, and that a skilful practitioner may avoid them if he pleases.
5. By the common method, you are sometimes at a loss to know whether the infection has taken place. The inflammation which appears about the wound, a few days after the operation, is looked upon as a sure proof; but there can be no certainty in this sign, unless you are well assured that it was produced by the variolous matter, and not by any other cause. This you can hardly be, when an incision is made; whereas there can be no doubt from a simple puncture. This presently heals up, and you clearly discern whether the succeeding inflammation is the effect of the needle, or of the infected matter. In the common way, you must take in the effects of the thread and of the putrid matter itself, not merely as conveying the infection, but as extraneous and offensive bodies: and to these are to be added the action of the plaister and of the air. These last causes may produce an inflammation, and about the edges of the cut that white eschar, which inoculators look upon as a decisive sign of the success of their operation. This inflammation often becomes erysipetalous, as in any other wound covered with a greasy plaister; and it may equally bring on pustules, which break out, suppurate, and vanish in one day.
The imperfect likeness of these effects to those of the virus, has sometimes misled inoculators; who, imagining that the venom had