Abstract
The chemical characterization of the substance responsible for the
phenomenon of “transformation” of pneumococci was presented in the now famous 1944
paper by Avery, MacLeod, and McCarty. Reception of this work was mixed. Although
interpreting their results as evidence that deoxyribonucleic acid (DNA) is the molecule
responsible for genetic changes was, at the time, controversial, this paper has been
retrospectively celebrated as providing such evidence. The mixed and changing assessment
of the evidence presented in the paper was due to the work’s interpretive flexibility –
the evidence was interpreted in various ways, and such interpretations were justified
given the neophytic state of molecular biology and methodological limitations of Avery’s
transformation studies. I argue that the changing context in which the evidence presented
by Avery’s group was interpreted partly explains the vicissitudes of the assessments of the
evidence. Two less compelling explanations of the reception are a myth-making account and
an appeal to the wartime historical context of its publication.