THE UNIVERSITY OF CHICAGO

CHICAGO 37+ ILLINOIS
DEPARTMENT OF MEDICINE
December 5, 1951

My dear Lederberg:

Thank you for your letter. I have asked Mrs. Barkulis
to write to you directly in reply to your question about her
work on Streptomycin-resistant mutants. She has quit work-
ing and gone domestic.

I am interested in your statement that you have a dis-
tinet impression that human and mouse strains of E. coli
differ in their fertility by your tests.

It was good to hear frem you. Please try to come and
see us tne next time you are in Uhicago.

My greetings to Mrs. Lederberg.

sincerely yours,

Pewarp bon —« ‘
CPM:1k U. Phillip Miller

Dr. Joshua Lederberg
Department of Genetics

The University of Wisconsin
Madison 6, Wisconsin