THE UNIVERSITY OF WISCONSIN
COLLEGE OF AGRICULTURE

Madison 6

DEPARTMENT OF GENETICS

February 19, 1962

Dr. Joshua Lederberg
Genetics Department
School of Medicine
Stanford University
Palo Alto, California
Dear Josh:
We need for our studies a mrtant of B subtilis
that requires cyste@in for growth. Would you be so
kind to send us this mutant if you have it available?

I would also appreciate having a reprint of your
recent work on the phase variation in Salmonella.

Best greetings.
Yours truly,
Ee
E. Freese

EF :rb

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