Jas. C. Kerr
James C. Kerr seems to have reinvented himself several times. In the Cincinnati City Directory for 1864 he is listed as "clerk,", in 1865 as "showman," in 1866 as "museum" and in 1868 as "Kerr, Dr, J.C., system renovator." Kerr's System Renovator was introduced at a cost of $1.50 per bottle, and six-cent black private die stamps were issued for it in September of 1869. A total of 31,133 were issued, all on old paper.
Toward the end of 1870 the cost per bottle was reduced to one dollar, so the six-cent stamps were not delivered after November of that year. The four-cent blue ones were first delivered in March of 1871 and last issued on June 23, 1882. 15,740 were printed on old paper, 70,875 on silk paper and 25,900 on watermarked paper. The copy shown is on watermarked paper.