FEDERAL SECURITY AGENCY
PUBLIC HEALTH SERVICE

 

IN REPLYING, ADDRESS THE
November 14, 1951

Communicable Disease Center

Enteric Bacterio]. Labo
P. O. Box 185 87 —

Chamblee, Georgia

Dr. Joshua Lederberg

The University of Wisconsin
College of Agriculture
Department of Genetics
Madison 6, Wisconsin

Dear Dr. Lederberg:

The phages requested in your letter of October 29
have been forwarded. I-trust that they are safely in your
hands by this time. I am sorry that a delay occurred in
forwarding these materials. It was my impression that they
were forwarded very soon after your request was received.
Upon a chance inquiry, I learned that they had not been sent
to that date.

I believe you will have no difficulty in the propagation
of the phages. We have found that very high titered phages
could be produced by placing 0.5 ml of the CTC of the phage and
0.5 ml of a young broth culture on a plate. The usual nutrient
agar is used for this purpose. First 0.5 ml of culture is placed
on the plate. ‘hen this has dried an equal amount of the diluted
phage is spread over the plate and this also is allowed to dry.
These plates are incubated either overnight or for 10 hours in
interrupted incubation. At conclusion of the period of incubation
the cultures are washed off with 5.0 ml of nutrient broth. This
is heated at 57.5 C for 30 minutes. The phages are then centri-
fuged and titrated.

Trusting that you have obtained good results with the
material, I am

Sincerely yours,

fL a2,

PRE: mg Philip R. Edwards, Ph. D.
Bacteriologist-in-Charge
Enteric Bacteriology Unit

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