November 13, 1956

Prof. R. W. Lewis
Migzhigan State University
E. Lansing, Michigan

Dear Dr. Lewis:

I have your request of the 12thffor a culture of S. typhimrium ani
information on its pathogenicity.

Dr. Norton Zinder at the Rockefeller Institute has been working on
this system, and mrely would be able to be more helpful than I could.
I have taken the liberty of forwarding your letter to hia.

Yours sincerely,

Jostma Lederberg
Professor ofGene tics