William H. Collins and Louis E. Collins are first mentioned as patent medicine wholesalers in Saint Louis in 1864. From 1867 at least through 1883 their business is shown as "patent medicines and druggists' fancy goods." Their private die stamp was first issued on January 2, 1867, and a second printing apparently took place in December, 1868, for a total of 231,000 stamps on old paper, only 196,900 of which were delivered. In September 1872 another 56,100 were printed, on silk paper this time, but most of these were not delivered. The copy above is on old paper.
A cover used by Collins Brothers in 1873.
The contents of the envelope above.