ATR MATL January 9, 1057

Dr, Je de Weigle

Division of Biology

California Institute of Technology
Pasadena |, California

Dear Dr, “eigle:

It has taken me too long a time to reply to your lettor of fecamber , and the
arrival from Madison of a copy of another (written in Mexico) prompts me to
catch up.

T have found some of your observations very interesting and in the whole not dise
cordant with my own. The exceptions, if they exist, my be antirely che result
of differences in sxperimental conditions. Rather than go into these now, I will
plan to have some discussions with you at the lysogeny meeting planned for Febru-
ary 15-17 by Bertani.

The observations of Cohen that you forwarded can be an explanation for some var~
jability in assay that I have experienced, but could not understand, excapt that
I believed it owing to temperature conditions during the early stages of growth
of infected cells,

wees
I have had a note from Kellenberger recently. He has forwarded copies of his
correspondence with the lederbergs and promises to keep me abreast of work ‘in
his laboratory. ‘Since I now have two copies of this correspondence {also one
from Madison), perhaps you would like one?

I am looking forward to meeting with you.
Sincerely,

My Le Morse, Ph.D.
MIM/mb

Pe5.t Am I correct in understanding that you use 12 tryptone as a growth medium,
and perform adsorptions as Kaiser, in M/100 MgSO)? I saw your manuscript only
briefly while passing through Madison, I gave a paper recently in New York (mostly
sumary), and will try to get a copy of the manuscript to you.

Me Le Me

cet Drs. Lederberg <=