\ oer February 9, 1954
ta

Dear Ole:
Greetings!

Iwas deeply interested to see your paper with Birch-Anderson on thin sections
of E. coli. Since seeing pictures like the one marked "b", enclosed, I have been
rather uneasy about too fwile mitotic interpretations. [But there has to be at least
a genetic equivalent of mitosis!]. This cell seems to concord mre closely with
the pictures from electron microscopy than most of the others— perhaps only because
the chromatin string is only occasionally unravelled.

I am hoping to follow up the technique myself, with Hans Ris' help. Have you made
any effort at ataining ami optical microscopy with the thin sections? I think a large

part of the difficulties in previous work may depend on the confusion of superjacent
layers.

Best wishes,

Joshua Lederberg