  This letter aims at justifying the stochastic equations in terms of the
number density variable, which are still controversial, via complementing
Dean's approach [Dean D S 1996 {\itshape J. Phys. A} {\bf 29} L613]. Our course
is twofold: First, we demonstrate that standard manipulations straightforwardly
transform the stochastic equation of density {\itshape operator}, derived by
Dean, to the Fokker-Planck equation for the (c-number) density distribution
functional $P(\{\rho\},t)$. Moreover, we verify the associated static solution
of $P(\{\rho\},t)$ with the help of the conditional grand canonical partition
function.
