H.R.C. Unit.

9th October, 1961.

i?r;jZ2S~~Or 8. L. Sinshsimsr,
Xvi&x2 of Siology,
3~liforniu Institute of Technology,
P339PAena, California,
U.S.A.

  @any thanks for your letter and the further invitation. I noull;l, be lost
refuckult to coie weut in February abecause L have to be in Saz: 3'r;~ici~co from
a'u0u-b ;w7 to 14 t:i or so of April, and could ye&haps marmage to cor~e to give a
@ol:oguil.m at Cd.2@&. trfter Mat and Just before X go kxue.  'C,-Juld :$&a.;; -0s
a suitable tiae?

Ze no'3 have conv&ncing genetic evidence -that the coding ratio is 3 or a
E2ultiple of 3.  It is not clear that IFC~ can prove that it is 3 rather khan 6,
but =;e ara trying.  I will send you a copy of a manuscript as soon as we
have one.  Jim Ofengand has also confirmed, in a prelimimry wayI that poly IT
makes polyphenalagqfne.

;;ith best ~,&hes,

F. H. C. Crbok.