A remarkable thirty-year old doctor named Nathan Davis founded the American Medical Association (AMA) in 1847. The recipient of a Doctor in Medicine degree at age 20, Davis established a medical school a little over ten years after founding the AMA; it would become the Northwestern University Medical School. Davis actively practiced medicine until his death at age 87.
In 1947 the United States released the Doctors Issue to commemorate the one hundredth anniversary of the founding of the AMA. Individual doctors, like Dr. Crawford Long and Dr. Walter Reed, had been honored in the Famous American Issue of 1940; but no stamp had been issued to commemorate the profession that has so positively impacted the lives of all Americans. A total 132,902,000 stamps of the 3-cent Doctors Issue were issued by the Post Office Department.