UNIVERSITY OF LONDON

eo Department of
Bacteriology,

POSTGRADUATE MEDICAL SCHOOL

‘ OF LONDON
Siren LONDON DUCANE ROAD
. SHEpherds Banh neo (4 lines) LONDON, W.12
6th.October,1950.
Dear Dr.Cavalli,
° I am making some headway

with my investigation into the question of
recombination in Bact.coli Kl2 but,just at
the moment,I am held up because I have no
threonine. If you have any to spare I
would be very grateful if you could let me
have about two grams to be going on with.
‘I have placed an order for this amino-acid
‘but, by the time the stuff arrives I expect
a month or so will have elapsed which I do
mot want to lose. When I get my own supply
I will at once return the amount you have
lent me - that is,of course,if you can.

As soon as I get any
definite results which I consider of any
value I will let you know about them,

Yours sincerely,

Vell PND

¥

(Dr William Hayes)