February 28, 1978
Dear Josh:
Thank you for your kind letter of February 14. I was, indeed, an early believer in the importance of DNA, so much so that I was trying to convince you at the 1946 Cold Spring Harbor Symposium that your recombination in E. coli is only a transformation.  But I have no recollection of the debate with Lwoff or Delbruck on this subject.  I don't have any written material on the reception of Avery's discovery in 1944, I only remember that Demerec told me about it in 1944;  we were both very intrigued but still cautious.  However, in 1946 I was already working (under Chargaff) on isolation of DNA from yeast (which up to that time was believed to contain only RNA ("yeast nucleic acid"); thus, Chargaff and I became early adherents to the glory of DNA.  Then, around 1948 our lab obtained chromatographic evidence that DNA is not a tetranucleotide. As you know, Mirsky and all the protein boys were the opponents: to them, in 1948 DNA was still just a prosthetic group,
Please do not hesitate to write to me if I can be of any historical help.
With best regards,
Stephen Zamenhof, Ph.D.
Professor of Microbial Genetics and Biological Chemistry