  Jeong-O Lee et al. [Phy. Rev. B, 61, R16 362 (2000)] reported
magnetoresistance and differential conductance measurements of multiwalled
carbon nanotubes. The observed aperiodic conductance fluctuations and the
negative magnetoresistance was interpreted to originate exclusively from
changes in the density of states at the Fermi energy. We show that this
interpretation is questionable and not supported by their measurements.
