It needs, however, constantly to be related to the rest of our knowledge, in the many human fields of research, study, and experience. (religion-online.org)
Salk identified the three main varieties of poliovirus, developed a killed - virus vaccine, tested it in monkeys, and in May 1952 proceeded with a massive human field trial on more than 400,000 children — the largest medical experiment ever conducted in the United States. (sciencemag.org)