March 14, 1961
Dear Salva:
I have enclosed a copy of the abstract that will appear in this year's Federation Proceedings.  Since it was submitted we have been able to separate the phage polymerase from the coli polymerase on a phosphocellulose column.  The separation is very decisive since the coli enzyme is eluted completely with a much weaker buffer and long before the phage polymerase comes off the column.  Another item of interest is that under conditions suitable for extensive net DNA synthesis with the coli enzyme (10- to 20-fold), the phage polymerase does not maintain the reaction beyond DNA increase of 50% at the most.  We are trying to figure out now just why the reaction stops so early and abruptly and hope to learn in due course why the phage polymerase requires a "single-stranded" primer.
Have a good time in Israel; our warmest regards to you and Zella.
Sincerely,
Arthur Kornberg