Columbia Gniversity
inthe Citpof Hew Pork

[NEW YORK 27,N. ¥.]

DEPARTMENT OF ZOOLOGY
January 11, 1947

Mr, Joshua Lederberg

Osborn Botanical Laboretories
Yale University

New Haven, Conn,

Dear Josh,

After my talk at C.S.H. this past summer I enouired
of Sol and Vernon and wes told that no discussions had
been submitted to follow my paper. However, now that I
have oroof I find 4 versons, including yourself, actually
did submit discussions for publication. On Demerec's OK
I am now working up my ow answers to these comments.

In order to achieve accurecy and continuity I must
ask to meke & chenge in your discussion. Pirie noted the
slope of the curve and the value for the leucine content
of wild tyoe which I mentioned and asked ebout the efficiency
of leucine utilization. I gave the accurate relation (2.3
inetead of 2.5) and referred the question to you for elabora-
tion. Hence, I propose that the discussion read as indicated
on the enclosed sheet.

Demerec wanted me to send you this revision, Ou?

Regards,
Sincerely, .
Francis J. Ryan
FIR:O'B

enclosure