WASHINGTON &

 

i) UNIVERSITY

  

 

 

SCHOOL OF MEDICINE

SAINT LOUIS (10)
DEPARTMENT OF BACTERIOLOGY AND IMMUNOLOGY

EUCLID AVENUE AND KINGSHIGHWAY

March 4, 1948

Dre Je Ledarterg

Dept. of Genetica
University of Wisconsin
Colle:ve of Agriculture
Madison, 6, Wisc.

Dear Josh:

Regarding your letter of March 2nd, it is akout
time you learned that in the observati.ns of nature,
when two apvarently dontradictory rasults are ottained,
it is not always inevitatly true that one must te
risht and one must te wrong. They both may te right

or they toth may be wrong.

a
. Riwnennbaas Yamal
Now with reapect to the particular protlem at

hand, we found that it was necessary to dilute the «gran
dyes in the EMB plate to the point which permits growt oud de EMB ras
This point is different for different atrains of y ’ . ..
and I am sorry tnat I am not in the position to give you destynect Kbike
the concentration that will permit MA and ma to develop. ,,..
All of our work was done with the galactose fermentin
system involving other strains. Tle general level we
found was 2 ca. of a 2% eosime and 1/2 aa. of a .5%
methylens bive per 100 cc. of mdia For the more
sensitive, of course, you would mve to go telow these
consentrations.

Sincerely yours,

Sok.

S. Spiege lnm”