October 1, 1957
Dear Dr. Lederberg,
In a Biology class laboratory we will be doing some experiments on osmotic phenomena and permeability.  In conjunction with these class tests, I would like to put across the idea of specific, active transport.
Therefore, I would greatly appreciate receiving as soon as convenient to you or your assistants, cultures of:
(1) K12 (wild[?] type)
(2) Lac1-  480
(3) Lac4-  W208
The secondary characteristics of the strains are unimportant so long as they do not alter the phenotype on EMB and "carbon source" medium.
Thank you very much for your attention to this request.
Sincerely yours,
Philip E. Hartman