Thomas W. Marsden was the manufacturer of Marsden's Pectoral Balm for coughts, colds and consumption, and Marsden's Carminative Syrup for diarrhoea, dysentery and cholera. His black, four-cent private proprietary stamp was issued only once, on August 20, 1866. 27,500 copies were printed, on old paper.
The price of the products must have been cut in half almost immediately, as he had a two-cent stamp printed in blue four months later. 26,250 of these were issued on old paper on December 13, 1866, and that was it so far as Marsden was concerned.