C. Arthur Knight was one of many virus researchers that Franklin visited during her 1954 trip to the United States. A colleague
of Wendell Stanley, Robley Williams, and Heinz Fraenkel-Conrat, he discussed in this letter a recent article Franklin had
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1955-01-11 (January 11, 1955)
Knight, C. A.
University of California, Berkeley
Original Repository: Churchill Archives Centre. The Papers of Rosalind Franklin
Reproduced with permission of the University of California, Berkeley.
Thank you very much for sending your manuscript in advance of publication. Several of us were very much interested in your
results, among them being Dr. Williams, from whom you have doubtless heard by now.
Dr. Fraenkel-Conrat and I found almost nothing to quarrel with you about on the chemical side and I, at least, am not able
to follow you very well on the crystallography. I might suggest in connection with the first page of the manuscript that
most people use the figure 6 percent for the quantity of RNA in TMV. The portion of the paper which interested me a great
deal is the evidence for the presence of some water within the viral particles. If this is really the case then we chemists
picture a variety of chemicals penetrating the interior of the virus to react with various things. I will, of course, have
to revise my argument concerning the location of the nucleic acid in the virus since it was based on the conception of an
In connection with the materials which we sent you, Dr, Fraenkel-Conrat says that the I-TMV contains about 0.74 percent iodine,
which is about one iodine per 17,000. More of this material is available if you want it. I am sorry that the samples did
not arrive in better condition and we shall try to send the next ones under moister conditions. The CV4 has a higher isoelectric
point than TMV and since it is insoluble in its isoelectric zone, is inclined to come out of solution as a white precipitate,
particularly when the salt concentration is low. You would probably find that the white precipitate you observed would dissolve
readily if a bit of dilute ammonia were added or dilute alkali of any kind. Addition of a trace of salt will also tend to
reduce gel formation exceedingly. We can provide more CV4 also if you should like to have it.
Since you did not request the return of the paper, may I assume that we may keep this for reference and further study?