It took me more than 6 months to answer your letter of April 12. A lot of work and a trip to Brazil--giving a course in Rio,
and lecturing around the country. But I did not forget your inquiry about lysogenic strain. I recently got it with the Shiga
strain, and, if you still are interested in receiving them, I'll send them right away. Please, tell me.
Lwoff is doing very nice work on lysogenesis. [. . .], in Italy, recently repeated with N. mustard, the mutation that I produced
in T2 by UV-raying the infected bacteria.