Department of Microbiology
School of Medicine

Western Reserve University
Cleveland €, Ohio

March 19, 1950

Dr, Joshua Lederberg
Department of Genetics
University of Wisconsin
Madison, Wisconsin

Dear Dr. Lederberg:

At the suggestion of Dr. S. #. Luria I am seeking to obtain from
you a transfer of a mutant strain of FE. coli, K-12, that he sent to
you in the summer or fall of 1948. The particular strain in question
had a requirement for adenine plus uracil, but would also grow when
given xanthine or guanine. I isolated this strain at Indiana while
working under Dr. Luria towards the masters degres in bactericlogy,
ond this is the first situation I have been im since leaving school
where the opportunity to do additional work with mutants has presented
itself. I am working under Dr. J. 0. Lampen at present and we are
interested partivularly in purine-pyrimidine me:abolism, Dr. Luris
has i.formed me that his strain of the orsanism is no longer viebls,
but that I might be able to get a culture from you. If you could
send me a strain of the organism I would be very grateful.

Very truly yours,

Jorg € ‘\ . -

George 0, Carrington