Rhode Island Revenue and  Postage Due Issue
Proprietary Stamps - Revenue Issues of 1862-71 & 1875-81
Scott #s R3c and RB11 - 1 Cent Washington Red and Green
With Dr. Seth Arnold - Woonsocket, R.I. Printed Cancels

I have seen several varieties of the Dr. Seth Arnold cancel including a circular CDS type of cancel.
The two Proprietary stamps pictured are Scott #3c, part of the first issue of Revenue stamps in 1862
and Scott RB11 issued from 1875 to 1881. Most early Revenue Stamps are canceled with script (Pen) cancels. Printed Cancels, such as the examples above command a higher premium.

Doctor Seth Arnold was born in 1799 and died on October 31, 1884. The first reference I can find for Dr. Arnold lists him as living in Smithfield, Rhode Island in 1849.

By 1864, he was residing in Woonsocket, Rhode Island and was the owner of the Dr. Seth Arnold Medicinal Corporation.  His two sons Olney and Seth Jr. were both employed by the firm and in 1880 Seth Jr. was appointed as the corresponding secretary to the firm. 

Dr. Arnold's firm produced several different varieties of patent medicines. The two best known of these were Dr. Seth Arnold's Cough Killer and Dr. Seth Arnold's Balsam. I don't know if Seth Arnold was an actual doctor or not; I couldn't find any references indicating that he had an actual degree. However, I was able to ascertain that the main ingredient in his Cough Killer was Morphine, (Even if it didn't cure you; after a few spoonfuls you probably wouldn't care.) Dr. Arnold's Cough Killer was also touted as a cure for Asthma. Arnold sold the right to his Balsam to Gilman Brothers of Boston Massachusetts in 1868 for $12,500.

I have two different dates for Dr. Arnolds death. A Rhode Island Cemetery Inscription  records it in 1884. A dealer in old bottles has a bio online listing it as 1892.

After his father's death, Seth Jr. moved to Connecticut and sold the company to Gilman Brothers in Boston.

What makes these items doubly interesting is that they cross two hobbies. The old bottles that housed Dr. Arnold's Patent Medicines are also considered very collectable and during my research, I came across a good many of these items offered for sale online.