December 5, 1957
Dear Roger:
We have just gotten back from our Australian trip and are doing our best to recover our work routine.  I had quite a good time down there in addition to an opportunity to branch out for a while in some other lines of work but I will forego telling you about that until I have a chance to see you, which I hope will be before too long.
The main point of writing you now was to ask whether you still have the strain of "Pseudomonas" originally labelled TR 13 and mentioned in a series of papers and in your note in the Journal of Bacteriology for December, 1952?  The reason for asking you about this is that Esther spent some time in Melbourne with Bruce Holloway who has been doing some quite competent work on genetic recombination in Pseudomonas.  There is a vague possibility, however, that some rather obscure interactions which Esther is now studying between Pseudomonas and Escherichia coli could be accounted for on grounds similar to your biochemical conclusions before the recognition of the taxonomic status of TR 13.  So if you still have a culture on it, we would like to have it on hand for possible comparative studies later on.
It took me quite a while to discover the reference to this 1952 paper and I still have it in the back of my mind that something has been said about this situation very much more recently.  Do you know of any subsequent comment on this particular confusion of the two species?
Sincerely yours,
Joshua Lederberg,
Professor of Medical Genetics