This paper extends and confirms the report of Calabrese (Calabrese, E. J. (2011b). Muller’s Nobel Lecture on dose-response for ionizing radiation: Ideology or science? Arch. Toxicol. 85, 1495–1498) that Hermann J. Muller knowingly made deceptive comments in his 1946 Nobel Prize Lecture (Muller, H. J. (1946). Nobel Prize Lecture. Stockholm, Sweden. Available at http://www.nobelprize.org/. Accessed December 12) concerning the dose-response. Supporting a linearity perspective, Muller stated there is “no escape from the conclusion that there is no threshold” while knowing the results of a recent study by Ernst Caspari and Curt Stern contradicted these comments. Recently uncovered private correspondence between Muller and Stern reveals Muller’s scientific assessment of the Caspari and Stern manuscript in a letter from Muller to Stern 5 weeks (14 January 1947) after his Nobel Prize Lecture of 12 December 1946. Muller indicated that the manuscript was of acceptable scientific quality; he indicated the manuscript should be published, but the findings needed replication because it significantly challenged the linearity hypothesis. These findings complement the previous letter (12 November 1946 letter from Muller to Stern), which revealed that Muller received the Caspari and Stern manuscript, recognized it as significant, and recommended its replication 5 weeks before his Nobel Prize Lecture. Muller therefore supported this position immediately before and after his Nobel Prize Lecture. Muller’s opinions on the Caspari and Stern manuscript therefore had not changed during the time leading up to his Lecture, supporting the premise that his Lecture comments were deceptive. These findings are of historical and practical significance because Muller’s comments were a notable contributory factor, changing how risks would be assessed for carcinogens (i.e., changing from a threshold to a linear model) throughout the 20th century to the present.