Columbia Anibversity
College of Physicians and Surgeons

630 WEST 168TH STREET
NEW YORK 32, N. Y.
DEPARTMENT OF BIOCHEMISTRY

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tee

October 16, 1956

Dr. Joshua Lederberg
Department of Genetics
University of Wisconsin
Madison 6, Wisconsin

Dear Dr. Lederberg:

I, of course, read with interest your recent
paper on the adaptive enzyme forming protoplasts
from Kj9.

I wonder if you have tried inducing the
protoplasts with ultraviolet for lambda formation?
If you have and were unsuccessful, I would be saved
a lot of time.

Thank you for the two slants which arrived.

Has anything developed on the histidineless
mutants?

I am sorry that my young lady associate,
Miss Rockenbach, decided--despite my urgings-<to go
to Vermont. The skiing, of all things, was the
deciding factor!
Sincerely yours,
Ernest Borek

EB: ef