  We consider linear cosmological perturbations on the background of a D-brane
gas in which the compact dimensions and the dilaton are stabilized. We focus on
long wavelength fluctuations and find that there are no instabilities. In
particular, the perturbation of the internal space performs damped oscillations
and decays in time. Therefore, the stabilization mechanism based on D-brane
gases in string theory remains valid in the presence of linearized
inhomogeneities.
