‘ poy UNIVERSITY OF LONDON

POSTGRADUATE MEDICAL SCHOOL
| OF LONDON
robdRAae “cok iONDON DUCANE ROAD
Tsene . ' LONDON, W.12

SHEpherds Bush 1260 (4 lines)
Department of Bacteriology.

ist Jénuéery, i952.

beer Dr. Céevelli,

i wes very pleased to get your letter of the 15th Decemher
telling me about your work end the wey in which it certainly
appeers to be complementery to mine. It wus very good of you
to let me know of this work end when I get any more informetion
of interest I will let you have it.

There is one thing I did not understand in your letter, and
thet is because I em not & geneticist. You sey thet one cf
your. ¢ims is to meke "strains which, on erossing, would not be
heterozygous for chromosome mutetions." I had élways considered
thet the work 'heterozygous' could only be aoplied to diploid
cells end I sssume thet you consider the two mutsents we are both
using tc be haploid, except perhsps for 6 generstion efter
?conjugation, or in the diploid strsins heving the 'Het' cene
described by Lederberg.

With best wishes for the New Yeer,

Yours sincerely,

sad

Dr. Le Cavalli, ,
Instituto Sieroterapico Milanese,
Milane,

Vie Darwin 20, Italy.