  In this Letter certain fundamental physics issues relating to recent theories
of so-called `spin quantum plasmas' are examined. It is shown that the
derivations and some of the results obtained in these theories contradict
well-established principles of quantum mechanics, especially in their treatment
of fermions and spin. The analysis presented suggests that the aforementioned
theories do not apply for any range of temperatures at the stated densities and
furthermore fail to make any experimentally accessible and testable
predictions.
