April 26, 1955

Dear Dr, Ledfson:

I would appreciate your extending a previous favor by furnishing
reprints of your more recent papers (1953-1955) on bacterial flagellation.
I have your 1951 (J. Bact.) and 1952 (J. Path. Bact.), but if any have
been received subsequently, they can no longer be found in ay file.

I am of course happy to continue to exchange, and take the opportunity
to forward the current enclosures.

Yours sincerely,

Q
‘Joshua Lederberg -

Frofesscr of Geretics

¢ at

P.S. What, if anything, do you make of Bisset's account of old-young

polarity in dividing bacteria’ It is an attractive idea that I would

like to be able to believe. However, in my own obapsvations on fission

of motile cells, both daughters have been equally motile at the moment

of separation (this is Salmonella). Perffapssome polar monotrichs would

be more suitable for looking at this. Have you any observations on the

point, or can you recommend or provide a culture that is quite characteristically
monotrichous (in which it may be suppused that flagallar development is
postponed relative to fission)?