fe. 6 1956

Mann Research Laboratories
136 Liberty Street
New York 6, N.Y.

Dear Mr. Mann:

At Dr. Boris Rotman's inatructions, I am shipping (Railway Express
postpaid) his sample of o—nitrophenyl—B-D-galactoside. My rough check
ia 350.1 — 277.7(tare) = 72.4 grams. 5 grams are indicated as having been
sold previously; another 5 grame may represent an order recently filled
to the University of Wisconsin.

I assume he will. have left you further advice. If got, you can contact
him through me at the Genetics Department, University of Wiesonsin.
Yours sincerely,

Joshua Lederberg