acted upon the body, and seeing no ensuing small-pox, hastily concluded, that either the subject was not susceptible of infection, or that these appearances were in him equal to the distemper, or the small-pox itself. Hence they pronounced him safe from ever catching it, and neglected to repeat the insertion. But a subsequent natural small-pox shewed that the inoculator was deceived by equivocal signs; and inoculation suffered from his oversight, or rather from the unavoidable uncertainty of the common method.
The enemies of the practice have never failed, upon these occasions, to depreciate it with the public; as most people are ignorant of the difference between being inoculated, and having the small-pox by inoculation; between equivocal signs and a real infection; the accidental suppuration of a wound, and that which necessarily succeeds the variolous fever; and lastly, between pimples that fill and dry off almost in one day, and the true pock, which keeps out nine days at least.
But the cicatrix remaining at the place of insertion, will be a standing monument of the success or failure of it. When the patient has really had the small-pox, this fear is either round, like the mark of a pustule, or oval; but always large enough to be evidently that of an ulcer, and not of a mere incision, as it is when the operation has failed.
By the puncture all errors are avoided. If it brings on ever so slight an inflammation, a few