duly 1, 1948,

Dr, Raymond Roepke,
Stamford Research Labe.,
American Cyanamid Company,
Stanford, Connecticut.
Dear Ray,

We're doing some work now on the genetics of Salmonella, in which the
problem of lysogenicity has arisen. One of our atrains (S=21) is a carrier
for a phage active on another (S36) and I'm interested to see whether
I can "disinfect" S21, Other methods having failed, I hope to try
some antiviral agents. I would have written to Dr. R. J. Pitegerald, but
I did not know whether he is still at Stamford. Could you get hold of
some “Phosphine GRN" (2-amino~9-(p-aminophenyl) seridiniun chloride) for

me. Thanks very mach,

a

Sincerely ?

| Joshua Lederberg
Aseistant Professor of Genetics.