July 23, 1965

Dr. T.L.V. Ulbricht

Head, Nucleic Acid Unit
Twyford Laboratories Limited
309, Elveden Road

London, N.W. 10, England

Dear Dr. Ulbricht:

Thank you for your letter of July J and for referring me to your very
exciting treatment of "The Optical Asymmetry of Metabolites" in the
Florkin and Mason compendium. I think you have dealt with the subject
in a much more lucid manner than I was able to, and I will certainly
endeavor to not overlook your review on any future occasion. Although
my memory does not serve me well, I think it entirely likely that I
have at least brushed up against your article before, but perhaps was
not in a sufficiently receptive mood at the time. However, I should at
least lay it on the table that the treatment of optical activity in
"Signs of Life” was written several years ago, the entire paper having
been in a draft version for quite a long time and having been used as 4

working paper at a number of meetings at which the strategies of exobiological
exploration were discussed.

While I certainly agree that direct optical measurements can be greatly
improved for the determination of optical activity, I still feel that
approaches based on chemical resolution are immeasurably more sensitive.-:
To some extent this has already been borne out in practice,as is hinted at
in several places, including the enclosed reprint, and we have certainly
far from reached the limit of detectivity in the way that the gas chromato-
graphic system has been set up.

One of my most urgent concerns about the further development of space explor-
ation programs is that they should provide the facilities whereby investigators
like yourself will be able to participate, brindng in the full breadth of your
own individual insight and power of experimental technique without imposing
the present obligation of very heavy involvement in engineering questions.

To do this premises some consensus as to what the most important issues really
are, and I hope you will not lose any convenient opportunity to express your-
self directly on the same matters.

/ yp’ LHUYATO
Dr. T.L.V. Ulbricht July 23, 1965
Page 2

To return to optical activity, I have a very strong impression that Pasteur
himself already understood the rational basis for the finding of optically
active metabolites ubiquitously in living systems. He was certainly very
much preoccupied with stereochemical specification, but I am not able to
point to any specific quotation in his writings on just this point.

Cordially,

Joshua Lederberg
Professor of Genetics

Enclosure:

Halpern, B. and J.W. Westley, 1965. High sensitivity optical resolution
of D,L amino acids by gas chromatography. Biochem. & Biophys. Res. Com.
19:361-363.