Which virologist's ideas did Franklin's equal-length TMV observation contradict?

Franklin’s observation that tobacco mosaic virus particles were equal in length contradicted the ideas of virologist Norman Pirie. In a 1955 Nature paper, she reported that TMV particles had a consistent length, challenging Pirie’s view of their size and structure.

The disagreement arose during Franklin’s work at Birkbeck College, where she used X-ray diffraction to investigate TMV, a rod-shaped RNA virus. Her results also supported the idea that the virus had a hollow core and a regular protein arrangement. Pirie, a prominent plant-virus researcher, did not accept the interpretation at first and subsequently stopped supplying Franklin with virus preparations.

Franklin’s conclusion was ultimately supported. Her collaboration with Aaron Klug helped establish important details of TMV architecture, including the placement of RNA along the inner surface of the hollow protein tube. Donald Caspar was a collaborator on related structural work, while Wendell Stanley was associated with earlier TMV purification research; neither is the virologist named in this specific dispute.