5 November 1956
Dear Dr. Lederberg,
About four years ago you sent to Dr. Cohen a strain of K12 called W-9 which had a requirement for bistin or uracil.  We would appreciate another slant of either that strain or any other pyrimidineless mutant of K12.
We are comparing the galactose utilization of various strains of coli.
Please use the Bainbridge St. address.
Many thanks,
Sincerely,
Hazel Barner