Scientific realists are committed to the claim that scientific discourse should be interpreted realistically, so that theoretical terms are understood as putatively referring expressions that have putative reference to empirical entities. In order to argue against realistic interpretation, I draw on an episode from the history of chemistry. One of the hypothetical entities of late 18th century chemistry was the muriatic radical, a hitherto unknown element that was thought to be a constituent of muriatic acid. I argue that the term (...) 'muriatic radical' resists realistic interpretation, and that we should therefore refrain from interpreting discourse concerning hypothetical entities realistically. (shrink)