May 12, 1939

Dr. Irving Langmuir

Research Laboratory

General Electric Company

1 River Road

Schenectady, New York

Dear Dr. Langmuir:

I am glad that you called to my attention the incorrect remarks which Dr. Niemaan and I had made in our paper regarding Bernal's statements. I was indeed aware that Bernal's statements were not accurate, and it was by accident that they were repeated nearly verbatim is our manuscript. This correction has now been made.

I think too that an experimental investigation of aldehyde ammonia is worth while, although it does not have much significance to the protein problem. There is no resonance energy involved here, and moreover the carbonyl bond energy in aldehyde is 3.5 kcal./mole less than in ketones and related substances. Consequently we would predict only 3 kcal./mole change in energy on formation of CH₃HCOHNH₂, and this value might well be further decreased by minor interactions within the molecule.

The principal reason which led Dr. Niemann and me to prepare our manuscript is that there has been a great deal of material published in support of the cyclol theory, and very little to support of the polypeptide chain theory. Dr. Niemann and I feel that the latter theory is right, and although we are unable at present to advance any rigorous argument in proof of this, it seemed worthwhile for us to state our beliefs.

I shall be on the lookout for the paper by Dr. Wrinch which is to appear soon in Nature.

The copy of the proof sheets of your Physical Society paper arrived yesterday, and I have read the paper with much interest. It seems

Dr. Irving Langmuir May 12, 1939

to me that the phenomena of denaturation are not incompatible with the simple polypeptide for the globular proteins, as you say, but are instead accounted for in a reasonable way. I am enclosing a reprint of a paper by Dr. Mirsky and myself which discusses this matter.

Sincerely yours,

Linus Pauling

LP/jr

Enclosure