March 9, 1954
Dear Dr. Clayton:
First may I thank you for the reprints on your work on phototaxis that you sent me some time ago.
I am writing now to inquire whether, in preparation for your thesis, you have accumulated any sort of bibliography on chemo- as well as as phototactic responses of bacteria.  We have run into a rather striking example of negative taxis on the part of Salmonella with respect to phenol, and I would be interested to know whether there is the basis of a definitive interpretation already in the literature.  We have had equally little luck in trying to find earlier literature on the energy metabolism of bacterial motility, and I would be grateful to you if you could refer me to anything that you may have run into on this subject too.
Yours sincerely,
Joshua Lederberg
Associate Professor of Genetics