not to be forward in publishing single cases of failures, real or supposed; for, when the weak minded and uninformed hear of these failures, without hearing at the same time that there are hundreds of cases of permanent security for every single case of failure, they are guided by the _exception_, which becomes to them the _rule_; their judgments being thereby most fatally perverted. As it is of the utmost consequence to establish the strong and important distinction between Small Pox, properly so called, and that which takes place after Vaccination, which may be called the mitigated, or five day Small Pox, a few of the most impressive testimonies respecting the safe nature of the latter may be here recited. Mr. Brown[4], of Musselburgh, gives the detail of forty-eight cases, in none of which did the secondary fever nor death occur. Here was a saving of at least eight lives, at the lowest computation; for this is the number which, by the average mortality of natural Small Pox, would have died if the constitutions of these forty-eight persons had not been modified by previous Vaccination. Dr. Dewar, of Edinburgh, hearing that many vaccinated subjects had been affected with Small Pox at Cupar in Fife, where the natural Small Pox at the same time prevailed, he most laudably repaired to the spot to investigate the subject. He found that fifty-four vaccinated subjects had caught the Small Pox. All these, except one, had the mitigated or five day eruptive fever, and livid. The fatal case was that of a child, who had a complication of other disorders, and having died on the fifth day, the Small Pox, according to its ordinary course of fatality, could not of itself be the cause of death. All the rest were safe; while of sixteen cases of the natural Small Pox at the same time and place, six died; so that, if these fifty-three cases had not undergone the mitigating process of Vaccination, nineteen or twenty would have perished. Between thirty and forty cases of the same kind have occurred at Carlisle, on the testimony of Dr. Barnes, a respectable practitioner of that city[5]. Many proofs might be adduced from the oral testimony of private practitioners, which would overswell this article. The only other to be mentioned is from the Report of the Central Committee of Vaccination at Paris, made in December last, in which the description of the disease occurring after Vaccination corresponds exactly with the mitigated five day cases which have occurred in Britain. They refuse the name of Small Pox to it; but as I know from my own observation, as well as from the testimony of others, that the matter from it does by Inoculation give the Small Pox, we can hardly, perhaps, with propriety deny it that name; but it should be distinguished by some strong discriminating epithet, such as is suggested above.