On Aug. 30, 1954, Bernice E. Eddy, a veteran scientist at the National Institutes of Health in Bethesda, Md., was checking a batch of a new polio vaccine for safety.Created by Jonas Salk, the vaccine was hailed as the miracle drug that would conquer the dreaded illness that killed and paralyzed children. Eddy’s job was to examine samples submitted by the companies planning to make it.As she checked a sample from Cutter Laboratories in Berkeley, Calif., she noticed that the vaccine designed to protect against the disease had instead given polio to a test monkey. Rather than containing killed virus to create immunity, the sample from Cutter contained live, infectious virus.