May 26, 1950

Dr, K, C, Atwood, III
Marine Biological Imboratory

Weode Role
Mansachueetts

Dear Keon

I an very pleased that you will be able to come here for
our meeting on the 10th and I an looxing forward to nneing
you at length,

On the basin of ay excerience with 3. colg I would hesitate
to assign any definite genetic mochanisn to killing on the basis
of kinetic data, Values for the parameters waieh you have nov
eetebiiehed indleste perhaos that each nuclous is behaving in
dependently and that the removal of the individual nucleus follows
a log linear, at ieuet empirically, Celis of R. cold are killed
expozentia ly by “ray but, like your own, the direct genetic
evidence dofinitely mutes out recessive lethal) mitation as an
important basia of killing,

I hope thit wa can heave an opvertunity to taik this thing
out during your visit. Feet regar - to larbara and the three

children,
Sincerely,
J. Lederbar .
Asea't Prof. of Genetics
SLtpa