INDIANA UNIVERSITY
BLOOMINGTON, INDIANA

May 23, 1949

Bacteriology Department

Dre Je Lederberg
Department of Genetics
University of Wisconsin
Madison, Wisconsin

Dear Joshua:

I forgot to tell you in Cincinnati that Kauffman
has asked me to "lead the discussion" on senetic
recombination in bacteria and phage at Snelter Island.
If o.ke with you, I plan to start with a few remarks
on comparative recombinolosy, then put you up for a
summary of the essentials of your work, and then let
people discuss it. Then I'll put Al up, then myself.
Tney have projector and blackboard, if you want theme

Regarding your comments on our Geneties paper, the
correction obviously consists in subtractine from the
total number of bacteria those with one or more active
particles, and calculate the bacteria with two or more

phages among the remaininre ones:
r
“Ki xe
t= (ett )e }e

In our experiments, this correction was always
negligible, since one cannot obtain date for r <3.
Por r © 3 the correction is of the order of See ©6OOf course,
this makes it impossible to use high multiplicities at
low doses. This is elso go in case of phages poorly
reactivated, since the optimum zone to test reactivation is
never velow r~5,

Itli see you in Long Island.

best regards,