phone : Telephone :
CHISK, LONDON, : SHEpherds Bush 1260 (4 lines)
UNIVERSITY OF LONDON

POSTGRADUATE MEDICAL SCHOOL OF LONDON
DUCANE ROAD, LONDON, W.12.

— Reply to 20 February,1953.

A letter and reprints of my antigen XII5 paper
are on their way. This is to ask if you would

be so good as to send me a subculture of a
streptomycin-sensitive Hfr strain. The strain

I have seems to have reverted completely to
Nfr/F+ and I am anxious to test the effect of

SM on the fertility of Hfr. My own spontaneously
derived Hfr strain is,unfortunately,STAzr,

Many thanks in advance! te ty -
ALE