  In this Comment we report a phenomenon identical to that observed in ({Y.
Sun, M. B. Salamon, K. Garnier and R. S. Averback, Phys. Rev. Lett. 91, 167206
(2003)}) for systems of NiFe{$_2$}O{$_4$} particles (mean size $\approx$ 3nm)
embedded in a SiO{$_2$} matrix with two different interparticle spacings 4 nm
(1) and 15 nm (2), which controls the strength of the dipolar interactions. Not
only do we find the memory effect to be present in the non-interacting sample
(2), indeed we find it to be {\em more} prominent than in the interacting case
(1). We demonstrate that this effect can be simply attributed to a
superposition of relaxation times of two sets of particles.
