_Unfeignedly affected with the unhappy Situation of the poor Sick in Country Places in *Swisserland*, where they are lost from a Scarcity of the best Assistance, and from a fatal Superfluity of the worst, my sole Purpose in writing this Treatise has been to serve, and to comfort them. I had intended it only for a small Extent of Country, with a moderate Number of Inhabitants; and was greatly surprized to find, that within five or six Months after its Publication, it was become one of the most extensively published Books in *Europe*; and one of those Treatises, on a scientific Subject, which has been perused by the greatest Number of Readers of all Ranks and Conditions. To consider such Success with Indifference, were to have been unworthy of it, which Demerit, at least on this Account, I cannot justly be charged with; since Indifference has not been my Case, who have felt, as I ought, this Gratification of Self-love; and which, under just and prudent Restrictions, may perhaps be even politically cherished; as the Delight naturally arising from having been approved, is a Source of that laudable Emulation, which has sometimes produced the most essential good Consequences to Society itself. For my own particular, I can truly aver, that my Satisfaction has been exquisitely heightened on this Occasion, as a Lover of my Species: since judging from the Success of this Work (a Success which has exceeded my utmost Expectations) of the Effects that may reasonably be expected from it, I am happily conscious of that Satisfaction, or even Joy, which every truly honest Man must receive, from rendering essential good Offices to others. Besides which, I have enjoyed, in its utmost Extent, that Satisfaction which every grateful Man must receive from the Approbation and Beneficence of his Sovereign, when I was distinguished with the precious Medal, which the illustrious Chamber of Health of the Republick of Berne honoured me with, a few Months after the Publication of this Treatise; together with a Letter still more estimable, as it assured me of the extraordinary Satisfaction the Republick had testified on the Impression of it; a Circumstance, which I could not avoid this publick Acknowledgement of, without the greatest Vanity and Ingratitude. This has also been a very influencing Motive with me, to exert my utmost Abilities in perfecting this new Edition, in which I have made many Alterations, that render it greatly preferable to the first; and of which Amendments I shall give a brief Account, after saying somewhat of the Editions, which have appeared elsewhere._