5933 DURCHESTER AVE.
CHICAGS, ILLINGIS BU637

ll October 1977

Dear Josh:

You are right, I haven't been doing much about the Tatum piece. Since
last April all of my time and energy have been spent on getting the
origin of maize finished up--planning, planting, tending, pollinating,
harvesting, etc., and have had little energy for anything else.

My other difficulty is that I don't see at all clearly how to do the
piece on Ed. Aside from our collaboration on the science project, which
was wholly satisfactory and highly rewarding, we were never close in
other respects. I hope you can do better on the latter.

ft am sure about the statement in my recollections piece that the approach
came to me in one of Ed's lectures on Nils Fries' determination of growth
requirements of various filamentous fungi. I believe it was the first
time Ed gave that course, in which case it ought to be easy to check the
Stanford records.

It was clearly on the basis of the Fries work that it occurred to me that
if we could work out the nutritional requirements of Neurospora, a far
more productive approach to the relation of genes to enzymes would be
available to us. As you know, at that time biotin had just become avail-
able in a concentrate sufficient for our purpose. From then on it was
clear we were on the right track,

As for the search for recombinants in E. coli, I had always assumed that
you and Ed had available the mutants Ed's masters degree student, Gray,
had isolated and identified as to requirements. From your latest note,
I gather this was not the case--that you might not even have known of
them, or if you did, did not make use of them. I am very clear about
suggesting to Tatum the Neurospora approach to bacteria, for I was well
aware of the Lincolng-Gowen paper,

Where do you go from here? I hope you'll see the light more clearly than
I, and that you'll take the initiative.

I have now received copies of all the pieces on Ed for the Rockefeller
University Service and am sending you Xerox copies of those and some other
material I have.
-2-

As for the MacElroy recollection: It doesn't seem inconsistent to me
in the time sequence of our Neurospora approach. I don't have written
records but since our first Neurospora paper was in the October 1991
issue of PNAS, we must have got well started on the research by the
summer of 1940 or earlier. Collecting stocks, determining nutritional

requirements and producing of appropriate mutants could hardly have
been done on a shorter time.

All the best,

ota