20 April 1953
Professor Max Delbruck
California Institute of Technology
I received your letter, to Harry Weaver, this morning, and immediately telephoned
He had not seen your letter yet, but after I told him what you had said, and what
my opinion was, he said that he would bring Watson over for the Virus Symposium.
He suggested that they might save money by having Watson stay here through the summer,
instead of returning to England. I pointed out that the work that Watson is doing
in collaboration with Crick is very important, and that it might well be important
enough to justify sending him back to Cambridge, even for the period of two months.
I judge that he agreed to do that, if necessary.
I was very deeply impressed by the Watson-Crick structure, I do not know whether you
know what put Corey and me off on the wrong track. The x-ray photographs that we
had, which had been made by Dr. Rich, and which are essentially identical with those
obtained some years ago by Astbury and Bell, are really the superposition of two patterns,
due to two different modifications of sodium thymonucloates. This had been discovered
a year or more ago by the King's College people, but they had not announced it, and
I did not know that this was so. Corey and I had tried to find the structure that
accounted for one of the principal features of one pattern, and simultaneously for
one of the principal features of the second pattern, Watson and Crick saw the x-ray
photographs made in King's College a couple of months ago, when they attended a seminar
there, and they immediately began work on the problem. The King's College people
had already derived one conclusion from the photographs, as to the nature of the helical
structure. Watson and Crick amplified this by the idea of complementariness between
purine and pyrimidine residues, and formulated
Professor Max Delbruck 20 April 1953
their structure. While there is still a chance that their stricture is wrong, I
think that it is highly probable that it is right. It has very important implications,
as you mention. It think that it is the most significant step forward that has been
taken for a long time.
cc: Professor Robert B. Corey