  In a recent Letter to PRL, Taleyarkhan and coauthors claim to observe DD
fusion produced by acoustic cavitation. Among other evidence, they provide a
proton recoil spectrum that they interpret as arising from 2.45 MeV DD fusion
neutrons. My analysis concludes the spectrum is inconsistent with 2.45 MeV
neutrons, cosmic background, or a PuBe source, but it is consistent with a
Cf-252 source.
