APR 2 0 1955

Dear Dr. Bisset:

Lately I read over again your report (1948 JGM) on the polarized
growth of bactirial cells, which I found most intriguing. Have you
done much more on this since? It may be qecially appealing becaass
some of my own studies on the fate of formazan granules may bear out
your idea of flbuddinglp, and I also find this a provoking notion to keep
in mind for some of our genetic studies on motility "t~&I.s~~ in Sti-
nella.

   There was one point, however, that I could not concur in from g
  own observations- the idea that the new-born Salmonella is essentially
non-flagellate. I have often watched S. typhimurium and others dividing
and especially noted that both daughter cells are promptly motile to an
equal degree.Since our strx are quite different, the discrepancy may
not be crucial, and perhaps it is optimistic in any event to try to recon-
'tile functional and morphological evidences. Alternatively, I may have
rpCA/Amderstood your writing: do you find this difference in flagellation in
cells dividing during the later logarithmic phase, or especially soon after
the germination of the tiocyst.  (It must take a long time to reach the
microcpst stags in my material; I have not noticed immotility in still viable
cultures):

I am not trying to press this point, as both our observations may well
be correct under the different circumstances. I did want to ask your comznt
on this approach to the problem, and to ask whether you had made any studies
yourself on the immediate development of motility in dividing cells.

I was disappointed not to find a reprint of this '48 paper ih r4y own file;
I had the impression, perhaps erroneous, you had once sent it to me. In any
event I would be grateful to you if you could keep me up to date on your
provocative papers, and I would be grateful whether I necessarily commit myself
to agreeing with all of them or not .+ I am of cpurse happy to continue exchange.

You q be interested to learn that I have lately learned how to find the

sexual stage of B. coli K-12: it proves to be a temporary conjugation, aather
like Paratmcium. Of the exconjugants, however, only one (the tlQ"> engenders
recombinants; the other remains viable but genetically pure. 3e have not yet
see any morphological details such as conjugation tubes, and I am quite openminded
about their existence,  The conjugal pairs do remain associated for an hour or
two; it takes some tricks to find them; over a third of the pairs do result in
genetic recombination.

mZith best regards,

Yours si.ncer&