. a TN eget.
~ _ Sa

ree,

INSTITUT FOR VIROLOGIE BERLINN4, den .APF4A2 25, 1964
AN DER MEDIZINISCHEN FAKULTAT Schumonnste, 207 21
Telefon 420015, App. 876
DER HUMBOLDT-UNIVERSITAT ZU BERLIN Bankverbindung: Deutsche Notenbank Berlin
HA. Rosenthal Kto.-Nr. 11.27 600

Prof. Dr. Jd. Lederberg

Dept. of Genetics
University of Wisconsin

Madison / Wise,
USA

Dear Prof. Lederberg:

For several weeks I tried to isolate a chloramphenicol resistant
mutant of E. coli B, but did not succeed,

I should like to ask you, whether you possess such a mutant oF
another one of E. coli that propagates phage T 2 or other T—phages.
Would you be so kind as to send me this mutant?

Thanking you for yourg troubles connected with it I remain

yours truly

(H.A. Rosenthal )

x bdo nit BED arggrl gp cmanll bn Goal”

Dr. L. L. Cavalli-Sforza
‘Istituto de Geneticd
Via Sant ‘Epifanio, 14
Pavia, Italy