 A variant of IBE is also used by Cresto (2008) to reconstruct the experiment by Avery that showed that the transforming principle in pneumococcus is DNA rather than protein. However, her conclusion is that, in this case, IBE is inconclusive. What it does show is that there was a rational disagreement, at the time, on the question of whether DNA was the transforming principle. Novick and Scholl (forthcoming) argue that Avery et al. were not relying on IBE; they actually had a stronger case conforming to the traditional vera causa ideal (see Section 5.2).