Letter from Salvador E. Luria to Joshua Lederberg

During World War II, a number of biologists and chemists, including Heidelberger, had worked on secret government and military research projects intended to develop vaccines and antidotes against microorganisms and toxins that were potential biological and chemical warfare agents, such as anthrax and, in Heidelberger's case, ricin. In order to develop such vaccines and antidotes, these scientists first had to purify the substances under study, thereby... making them more potent. Several of the scientists involved, including Luria and Heidelberger, were troubled by this blurring between offensive and defensive biological and chemical weapons research. After the war, they campaigned for a ban on secret research of this kind.