If we refer to the tables (No. 1 and 2), we shall find that from the years 1752 to 1798 inclusive (the period during which inoculation was most extensively employed in this country), the average mortality from Small Pox, during periods of five years each, was occasionally so high as one in eight of the whole, and rarely less than one in ten. And that during individual years, it three times (in 1752, 1781, and 1796) amounted to nearly one in five; and in 1772 was little less than one in six. This is surely a fearful encrease on Dr. Jurin’s calculation—“That of all the children that are born, there will some time or other die of Small Pox _one in fourteen_.” There can be no doubt, however, that this immense encrease of mortality from Small Pox was owing to the extended practice of inoculation; and until this could have been pursued more generally, and with greater precautions, so as at once to diminish the numbers capable of being infected by the inoculated, and the hazard of the latter coming into contact with the unprotected, I am disposed to think this fact was in itself sufficient ground for discontinuing inoculation for Small Pox altogether. Could every child have been subjected to the process of inoculation, before any exposure to the infection of natural Small Pox had taken place, the case would have been widely different: but it can scarcely be considered either just or politic to render one individual secure at the risk of endangering many, or with a certainty of destroying some. It may fairly be concluded, then, that inoculation for Small Pox, as practised for the last fifty years of the eighteenth century, although certainly _a great individual good_, was, in reality, without a doubt, a _most serious general evil_. From what has been hitherto stated, I conceive, we are authorised in assuming the following as facts, which will furnish a satisfactory answer to the first of the questions proposed, What were the destructive consequences of Small Pox previous to the introduction of Vaccination? 1. Small Pox is a disease of so infectious a nature, that few individuals passed through life without suffering from an attack of it. 2. It was attended with so much danger as to occasion the death of one in five or six of those affected by it in the natural way; and previous to the use of inoculation, one in fourteen of the whole number of children born, at one time or other, died of the Small Pox. 3. Of those who recovered, many suffered materially from its effects, not only in the disfigurement of countenance occasioned by it, but frequently in the loss of one or both eyes, or in irreparable injury of their constitutions. 4. After having been once affected by Small Pox, a very considerable proportion of individuals resist entirely a second attack: but still in very many instances a recurrence of the disease is proved to have taken place.