Just something interesting I found in the stacks.
The pamphlet is from the Polk Diphtheria Cure Co. of Boston, Massachusetts, though the “cure” itself seems to have been invented by Leonidas Lafayette Polk (1837-1892). An agrarian and Populist leader, Polk also founded the Progressive Farmer and was North Carolina’s first commissioner of agriculture.
Polk’s papers, including those relating to his diptheria cure, can be found at the Southern Historical Collection: http://www.lib.unc.edu/mss/inv/p/Polk,L.L.html.
Maggie, thanks! If only I had dug a little further!