From Ohio History Central
Fremont, Ohio, resident Charles Stilwell was a mechanical engineer. He dedicated his free time to manufacturing an improved paper bag. Paper or grocery bags already existed, but they were not easy to fold or to store. They also could not stand on their own because of their v-shaped bottom. On June 12, 1883, the U.S. Patent Office granted Stilwell a patent for a machine that manufactured a flat- or square-bottom bag. The bag also had pleated sides. The square bottom allowed the bags to stand on their own, while the pleats permitted easy folding and storage of the bag when it was not in use. Stilwell named his bag the "S.O.S." or the Self-Opening Sack because of the bag's ability to remain standing and open without the assistance of a person.
Stilwell's invention dramatically improved the paper bag, making it much more desirable to American consumers. In essence, Stilwell's bag was the precursor of modern-day paper bags. In 2000, Americans used approximately forty billion grocery bags based on Stilwell's original design.