DEPARTMENT OF
NATIONAL HEALTH AND WELFARE

CANADA

LABORATORY OF HYGIENE,

IN YOUR REPLY REFER TO FILE No. OTTAWA

20M—5-51—P2399

January 16, 1953.

Dr. Joshua Lederberg,
Department of Genetics,
University of Wisconsin,
MADISON, Wis.,

U. S. A.W

Dear Doctor Lederberg,

Many thanks indeed for the reprints "Genetic
Exchange in Salmonella" (with the addendum included),
"Replica plating and indirect selection of bacterial
Mutants" and. "Recombination analysis of Bacterial
Heredity" which arrived safely.

Yours sincerely, .

L Rect Ki

W. Robert Bail