Lee & Osgood
Doctor Charles Osgood introduced Dr. Osgood's India Cholagogue in 1830, and in the following year wrote a sixteen page pamphlet, The Causes, Treatment, and Cure of Fever and Ague, and other Diseases of Bilious Climates, to include with each bottle. He teamed up with Charles Lee until the latter's death or retirement in 1870.
The company's private die proprietary stamp was delivered first in February of 1866 and thereafter until October 1, 1880. 132,100 were issued on old paper, 74,000 on silk paper and 21,000 on watermarked paper. This copy is on silk paper.
The firm, as Charles Osgood and Company, was instrumental in having the six-cent first issue proprietary stamp issued, and the company's cancel is the most common one to be found on it, if any can be called common. Here is the cancel on a six-cent stamp of the 1875-81 proprietary issue.