Thank you very much for the most interesting report on cultures 5731-5745-52. As you will have noted, each of these diagnoses
agrees with the genetic prediction, excepting the identification of z33, and the diphasicity of 5744, which was an open question.
I do not think it will be necessary for me to burden you with any further large groups of recombination serotypes after the
present batch which you have already in hand. Enough has been done to support the generality of the process. For the next
couple of months I will concentrate on the details of more restricted combinations, to help solidify the genetic theory. Then,
I will be in a better position to collaborate with you more closely at Chambles when I visit, and to emphasize some of the
broader serotypic problems.
5744-32 (g, p:1,2) worries me somewhat. Here is a combination that is not, as far as I know, represented I the diagnostic
scheme. The experimental result shows that its absence is not due to any inconsistency with genetic possibilities. It may
raise the question of the importance of the transduction process in nature. Alternatively, this combination may be somehow
maladapted for reasons that we cannot now penetrate. On the other hand, 5745-52 (IV V XIII) provides at least a possible hint
for the origin of the monophasic "reading" studied by Cherry and yourself some time ago.
A few materials would be of some help for my immediate further work. They are, if available, some z33 serum; the java strain
from which #157 was originally isolated; and, to help clear up a point of confusion that arose recently, another sub. of #6
(S. paratyphi b, predominantly 1, 2).
I am sorry not to have emphasized this in my letter: SW-666 is a galactose-negative mutant of Kauffmann's #248. It was
used instead of #248 in most of the transduction experiments, as the marker is a control on contamination. The anomalous b-agglutination
occurred in a SW-666 culture which proved to be largely rough. It is still there in the original broth mixture, but all of
the isolated colonies are either spontaneously or in-agglutinable, so I would assume that the apparent b-reaction is an artefact.
I will send the original #248 in a future shipment, but will assume that SW-666 can be used as its serological equivalent.