22 December 1955

Dear Anita and Linus:

Under separate cover I am sending you a copy of the Annual Report of the Division of Chemistry and Chemical Engineering for last year, and also a copy of the Report of the President of the California Institute of Technology. Perhaps you will be interested in some of the information about the work going on here.

I am feeling very pleased right now, because a couple of months ago I had a new idea about the way to determine the structure of a globular protein, such as hemoglobin or insulin. Many x-ray people have been working on this problem-for example, Perutz and Kendrew have devoted practically their full time to it for a decade or more, and Harker and half a dozen assistants in New York have been on the same job for about five years. The results obtained so far have been disappointing, because the x-ray methods are not sufficiently powerful enough to enable a straightforward attack on the problem to be made, and until recently I had not seen any way of doing the job, and had felt that we should not get involved in it. Then the new idea turned up, which consists in using certain inorganic complexes, containing 18 moderately heavy atoms, as the fiducial point in the crystals, in place of a single heavy atom (mercury or uranium), as has been tried before. In addition, we are planning to make use of the phenomenon of anomalous dispersion to decide between two alternative values of the phase of the scattered x-ray beam from each crystallographic plane. We are hoping to apply these ideas in a vigorous attack on the problem of the structure of globular proteins. I am afraid that it may take ten years to determine a single structure, but perhaps the job can be done in five years. I think that we shall try to determine the structure of insulin, in case that insulin can be made to form crystals with the inorganic complexes that we need to introduce to serve to mark the corner of the unit cell in the crystal.

Mama and I made a four-day trip to Texas a couple of weeks ago, in order to attend an international conference on molecular quantum mechanics. We found it interesting, but tiring enough for me to decide that I should not go to MGH this year for the annual meeting of the Scientific Advisory Board.

Crellin came home three days ago. He seems to be more interested in his work than before. He is taking organic chemistry this year, and has been allowed to start on a research problem. We are considering introducing organic chemistry in the sophomore year here at the Institute.

Please give my love to all of the children.

Much love from

Linus Pauling:W