13th March, 1957.
Dear Miss Franklin,
From the symptoms now showing on the plants I inoculated with the virus you sent me last month, I have no reason to think that it was anything except a preparation of normal tobacco mosaic virus.  Certainly none of the plants is showing the kind of symptoms that Holmes describes as typical of infection by the rib grass strain.  Of course I am doing my tests in a different environment, and also am using different varieties of test plants from him, hence my results are not conclusive.  If you have any quantity of the preparation left, I suggest a critical test for its identity would be to get someone to analyze it for the amino acids that are specific to rib grass strain, for instance, histidine and methionine.  Until this has been done I think the fact that you get X-ray patterns similar to those given by the type strain TMV is readily explained by the assumption that your rib grass is, in fact, TMV.
Yours sincerely,
F.C. Bawden