title: Comment on "Magnetoviscosity and relaxation in ferrofluids".
abstract: It is shown and discussed how the conventional system of hydrodynamic equations for ferrofluids was derived. The set consists of the equation of fluid motion, the Maxwell equations, and the magnetization equation. The latter was recently revised by Felderhof [Phys. Rev. E 62, 3848 (2000)]. His phenomenological magnetization equation looks rather like our corresponding equation, but leads to wrong consequences for the dependence of ferrofluid viscosity and magnetization relaxation time on magnetic field.
authors.affiliation: Department of Mechanical Engineering, Ben-Gurion University of the Negev, P.O.B. 653, Beer-Sheva 84105, Israel.
authors.forename: M I
authors.initials: MI
authors.lastname: Shliomis