(seh y] aye

wor September 22, 1948.

Dear Lillfian,
*@ keep all our media in the fowm of dry mixes, and have found this very

convenient and accurate, especially from the point of view of having untrained

personnel mike up occasional small batches,

AQ The dyes: K HPC, (anhydr) 200 ge
Fosin Y 40 2.
Methylene Blue.HCL 6.5 g.

Use in a final amount of 2.4 g/l.

( This on be udded either to a complete or a synthetic agar. Our “gomplete" is:
per 1.

Casein Digeas ("\-2ZCase) 8 g.
Yeaes’ *xtract lL g.
NaCl (not easentiil) 5 2.
Lactose 10 2.
Agar 15 ge

The synthetic used for this purpose is:

Gae)os Succinate 5 ge
HH, ) 980 5
Nal i= 4 190
gs0, 1

A gar’ 15.

i@ have tried a nunber of other non-acid-producing C sources, and of them asparagine

is the only one that can compete with succinate. The synthetic "FB", or TNS as we call
it is a little trickier than the complete, but there is usually no difficulty in
reading ¢ or = colonies when grown ut 37, 36-48 hours.

“sther and“I will be “ast the ed of next month, and hone to see you then.
best regards,

Sincerely,