January 1, 1957

~

Ce
Deer Norton: pow

We will be happy to see you on your way West. It would probably be
more convenient for us if you visited on your way outs we will be going
to England in March, and will be increasingly busy through February.

Rivers and the polio foundation don't seam to have been very gracious
about your trip to Geneva, I don't know what re there would be to fili-
I can hardly think of anything the poliovirolgists ‘would want to hear, and
haven'b already. In any case, what you would have to offer would met be

entirely distinctive, and more power to you.

Did I answer your last letter yet? The medium for plating L colonies
is penassay broth + 10% sucrose + 1.5% agar + 1000 uf/ml penicillin, fortified
with an additional ,5% meat extract, Not all K12 strains work in this, e.¢.,
Kl2 itself is rather poor, but some of the mutants give c. 4 as many I-
colonies as viable counts. There is no obvious correlation in yield of L
colonies with any knowm genotypic facgor. If you're gofng into this with
lysozyme, let me know how it goes.

happy new year,

    
 

a, [Arr \.
Joshua Lederberg