English: Standing left to right, this 1966 image showed Dr. Donald A. Henderson, Dr. J. Donald Millar, Dr. John J. Witte, and, Dr. Leo Morris, standing in one of the Centers for Disease Control and Prevention’s (CDC) former offices discussing what may have been epidemiologic findings related to the eradication of smallpox, an effort in which the CDC was integrally involved at the time. Dr. Donald A. Henderson, headed the international effort during the 1960s to eradicate smallpox. Dr. J. Donald Millar, was the former Director of the National Institute for Occupational Safety and Health (NIOSH) from 1981 through 1993 From 1963 until 1970, he directed CDC's Smallpox Eradication Program. Dr. John J. Witte, was the former Chief of the organization’s Immunization Branch, and Dr. Leo Morris who specialized in statistical analysis, and implementation of the newly-introduced jet injector vaccine-delivery system in the battle against smallpox.