NEW YORK UNIVERSITY-BELLEVUE MEDICAL CENTER

NEW YORK UNIVERSITY COLLEGE OF MEDICINE

550 FIRST AVENUE, NEW YORK 16, N. Y.

DEPARTMENT OF PHARMACOLOGY November 29, 1956 OREGON 9-3200

Dr. Joshua Lederberg
University of Wisconsin
College of Agriculture
Madison 6, Wisconsin

Dear Joshua:

Thanks a lot for letting me know about Boris Rotman. Assuming that I can
get a supplementary grant from the government that will take care of his salary,
I have written to offer him a position here, and I'm really delighted at the
prospect. I've seen enough of him to overcome the obstacle raised by his
spe@&ch defect, and I'm convinced that he would be a real joy to have around.
I’m grateful to you for having taken the trouble to furnish detailed evidence
supporting this impression. I hope it works out well.

A gersion of the DAP manuscript was prepared quite a while ago, but I keep
delaying anything further with it while trying to straighten out pups details.
For one Thing, the cells continue to grow in absence of DAP qaime%a deal longer
than in the presence of penicillin,and while they are osmotically more fragile
than intact cells they don't look ‘anything like the spherical protoplasts you
get with penicillin. This work was based on an arbitrary period of incubation
of three of four hours. Now I am trying to see what happens when their growth
has come to a halt. On the whole, the last few weeks of work have consisted of
pretty dull little details, but I'm compulsive about my feeling that anybody
who introduces a method has an obligation to bring it to a reasonable state of
perfection. So it will probably be another few weeks before I can send you
something. .

A side product of this research that I've got very much interested in is
the fact that cells decrease enormously in optical density soon after they have
been immersed in 20% sucrose. The change takes piace over a period of 10-15
minutes, and it is very much slowed by cooling, so it looks to me as though
even water transpcrt out of the bacterial cells requires active metabolic work.

With best regards.
' Sincerely,

Gorrece

Bernard D. Davis
 

Ov