(Communicable Disease Center
(c/o Dr. P. Re Edwardes
(Box 185, Chamblee, Ga.)

February 4, 1955

Dear Professor Creze

Thank you for your letter of January 18, and its suweary of your
results. I regret thet my reply has been delayed by this brief visit
to Dr. Edwarde' laboratory.

I have mentioned in a previous letter to Dr. Felix the resulte that
you had communicated to me. I am sure that he will] interested to hear
from you, and I am equally sure that his critical counsel will be most
valuable. He has mentioned to me (in snother connection) that S. typhi
R901 hes in fact giveh rise th a Vie form (type Bl) by nouse passage.

ZI am not expert on this subject, but wonder whether an A typing might
not result from eo-called “degradation” of a more specific Vie strain.

ZI do not doubt that the publication of your results would be of con-
siderable interest, although I would hope that this 4s only introddotory
to a more detailed investigation of the mechaniew of the alterag$ion.
However, I also believe that a consul&aétion with Dr. Felix 4n order to
take adventege of hie long experience both with Vi typing and with his
strain H90l is indispensable.

I shall be most interested to hear of any further developments in
your experiments.

Yours most sincerely

Joshua Lederberg

(Please address any reply to Madison)