INST. FOR CELLFORSKNING OCH GENETIK
MEDICINSKA NOBELINSTITUTET
KAROLINSKA INSTITUTET
STOCKHOLM 60
Telefon 23 5480

Stockholm, May 11. 1960.

INST. FOR CELL RESEARCH AND GENETICS
KAROLINSKA INSTITUTET
STOCKHOLM 60

Dr. J. Lederberg
Stanford University
Department of Genetics
Palo Alto, California, USA

Dear Dr. Lederberg;

Thank you for your letter of April 26. You were right in judging my
attitude towards the inquiries of Dr. Mack. At present we are widening the
scope of work of the institute, partly.thanks to an extension of our grant from
the US Public Health Service. Because of that I feel as a responsibility to be
cautious about new activities. Dr. Mack obviously was not in a position to
convey to me an impression of a very realistic program - the only type of
project I would be interested in entering into under the present circumstances.

However, the information in your letter gives me the feeling that it
is a real and realistic approach to a very great problem and under such con-
ditions I will of course be very happy to assist in any way which I can. It
would be nice to talk the matter over with you. Perhaps there might be a possi-
bility this fall when I will be for a period of about 6 weeks in the United States.

The ultraviolet optics you refer to were built according to my speci-~
fications by Zeiss to suit the ultramicrospectrophotometer they are now pro-
ducing commercially, built with our machine as a model. The Zeiss people
made a remarkable job in the calculations of these optics and it is beyond doubt
in my view that they will be by far more suitable than any other existing systems
to your present purpose, Only a few objectives exist, however, and the first
of the high power systems has not even left the factory as yet. Within the next
days Dr. Trapp will come up and stay in Stockholm for a time testing the first
machine the Zeiss people have produced, which is just now set up in Stockholm.
I will take up your questions with him and I am sure that something can be
managed in a reasonable time. It is possible that a special objective should be
built for your purpose which . should, however, not be very difficult to do now.

I will let hear from me again and will also pick together some of our
old reprints on the field.

With personal regards to Mrs. Lederberg and yourself, I am,

Very sincerely yours,

Torbjérh Caspersson

TC:dn