THE UPJOHN GOMPANY

FINE PHARMACEUTIGALS SINCE 1886
KALAMAZOO, MICHIGAN

January 16, 1961

CLINICAL RESEARCH
GLINICAL PHARMACOLOGY SECTION

OFFICE OF
JOSEPH P. WEBB, M.D.

Joshua Lederberg, Ph. D.
Professor of Genetics
Stanford University
Medical School

Stanford, California

Dear Dr. Lederberg:

Our representative, Mr. Wendell Basham, has written to us concerning your
interest in the possible use of Gelfoam to use as a filter for the
collection of microorganisms. As you know, some work has been done along
this line and Gelfoam is being used to trap air-borne organisms. The
Gelfoam can be transferred to a fluid medium from which plates can be

poured. The Gelfoam is slowly soluble in water and can either be discarded
or incorporated into the poured plate if it has not completely disintegrated.

Mr. Basham is in error in stating that our commercial Gelfoam has been
treated with formalin. This was formerly the case but for the past several
years all Gelfoam has consisted only of pure gelatin. As first made,
Gelfoam is fairly readily soluble in water but the solubility is affected
by the prolonged heat necessary to sterilize the material. If the

Gelfoam could be sterilized by cathode ray or ethylene oxide it would be
much more readily soluble than is the present product. Dr. George Honeywell
of our organization is planning some experiments along this line but he

does not feel, at present, that the Gelfoam needs to be soluble to be used
in bacteriological work.

Perhaps our understanding of your problem is not complete. In any case,
I would be glad to hear from you further and Dr. Honeywell and I would
be happy te help in any way we can.
Sincerely yours,
THE UPJOHN COMPANY
slg
Joseph P. Webb, M. D.

JPW: sds