It has long been realised that superfluid helium cannot rotate bodily: it is believed that, instead, rotation of the container may result in the formation of one or more individual quantised vortex lines. Particular interest therefore attaches to a report by Williams and Packard of the University of California at Berkeley in a recent issue of Physical Review Letters (33, 280; 1974) that they have been successful in obtaining photographs apparently showing for the first time the positions of individual vortex lines in superfluid 4He.