RC (DLC); addressed: “Thomas Jefferson President of the United States Washington City”; franked and postmarked. Recorded in SJL as received 1 May. Enclosure: A Comparative view of the Natural Small-Pox, Inoculated Small-Pox, and Vaccination in their effects on Individuals and Society, a broadside printed by Jane Aitken in Philadelphia, dated 25 Apr.; comparing in three columns the potential physical effects of smallpox, smallpox inoculation, and vaccination, concluding that contracting smallpox is equivalent to “attempting to cross a large and rapid stream by swimming, when one in six perish,” that inoculation using smallpox is equivalent to “passing the river in a boat subject to accidents, where one in 300 perish, and one in 40 suffer partially,” and that vaccination with cowpox is equivalent to “passing over a safe bridge”; presenting also a statement of 12 Apr. by 50 physicians of Philadelphia, including Benjamin Rush, Caspar Wistar, John Redman Coxe, and Benjamin Smith Barton, declaring it “a duty thus publicly to declare our opinion” that cowpox vaccination is a safe and “certain preventive” of smallpox, and they recommend it for general use; with a statement by the board of managers of the Philadelphia Dispensary that the institution’s attending and consulting physicians, after 18 months’ experience with cowpox vaccination and finding it to be “mild, unattended with danger, and a full security against the Small-Pox,” wish the procedure to be made available through the Dispensary; accordingly, the managers announce that doctors will perform cowpox vaccination there daily; “the poor of the city” are encouraged “to embrace the means now offered of preserving themselves and families from a dangerous and loathsome disease” (Shaw-Shoemaker description begins Ralph R. Shaw and Richard H. Shoemaker, comps., American Bibliography: A Preliminary Checklist for 1801–1819, New York, 1958–63, 22 vols. description ends , No. 3998).