DEPARTMENT OF VIRUS RESEARCH May, 9th 1953
KAROLINSKA INSTITUTET
BOX 764 STOCKHOLM 1
SWEDEN

Dr. Joshua Lederberg
College of Argriculture
University of Wisconsin

Madison 6, Wisconsin.

Dear Doctor Lederberg,

I want to thank you for the very interesting reprints I have
received from you. The subject of flagellation, mobility of flagella,
and phase variation is oneg which has interested me enormously and
I have spent much time and many efforts in trying to find an answer to
some of the many puzzling questions concerned with these phenomena. rT
am still engaged in some work along these lines. For instance, in co-
operation with Dr. Weibull and Dr. Heller I am now studying some of the
problems concerning the antigenic structure of the Proteus flagella.

Your beautiful experiments have given the answers to most of the
questions I have been asking myself. I am looking forward to reading
your future articles on the matter.

In the meantime I have sent those old reprints you particularly
asked for. I hope they have already safely arrived.

With kindest regards,
Yours sincerely

ure Cael

Sven Gard