FEDERAL SECURITY AGENCY o Public Health Service
NATIONAL INSTITUTES OF HEALTH o Bethesda 14, Md.

Dr. Joshua Lederberg
University of 'Jvisconsin
Madison, Wisconsin

Dear Dr. Lederberg:

You have probably received an inordinate number of requests for
the K-l.2 strain of & coli, but I wonder whether you would find
,it possible to send me one as well.  I have obtained from Dr. van
Niel the several deficient strains you were good enough to supply
him for his use in the course irl microbiology, but unfortunately,
i&r. Lara did not have the original strain.

Your help would be greatly appreciated. i