Letter from Thomas Gold to Dr Melvin Calvin, Director, Laboaratory of Chemical Biodynamics, University of California, Berkeley, California Encloses the completed paper. Gold's accident caused some delay, but also the stream of evidence that came to light was most welcome but slowed up the writing. Discusses some of the problems. Post script; Asks him to distribute the paper to Drs Lemmon and Otvos. Has copies of most of the literature cited. 1 December 1977