MERCK & CO. INC.

RAHWAY, N. J.

RESEARCH & DEVELOPMENT DIVISION October 23, 1947

AIR MAIL

Dr. Joshua Lederberg

Assistant Professor of Genetics
The University of Wisconsin
College of Agriculture

Madison 6, Wisconsin

Dear Dr. Lederberg:

In response to your letter of October 10,
we referred your question in regard to the avail-
ability of desthiobiotin to Dr. Karl Folkers,
Director of our Organic and Biochemical Research
Department, who replied that dl-desthiobiotin is

more available potentially than biotin but that we
have made no particular effort to prepare large
samples of desthiobiotin.

You have no doubt received by this time the
samples of biotin and 4-methyl-5-8-hydroxyethyl thia-
zole, which were sent later than the other five items.

If we can be of any further help to you,
please feel free to ask,

Sincerely yours,

e,.wW oe ew h
C. Woodruff
Director, Microbiological Research

JCW/ jef