Magnetoconductance Noise and Irreversibilities in Submicron Wires of Spin-Glass ${\mathit{n}}^{+}-{\mathrm{Cd}}_{1-\mathit{x}}{\mathrm{Mn}}_{\mathit{x}}\mathrm{Te}$

Signatures of spin-glass freezing such as the appearance of $1/f$ conductance noise, the recovery of universal conductance fluctuations, aging, as well as magnetic and thermal irreversibilities, are detected in mesoscopic wires of ${\mathrm{Cd}}_{1-x}{\mathrm{Mn}}_x\mathrm{Te}$:I at millikelvin temperatures. Spectral characteristics of conductance time series are consistent with the droplet model of short-range spin glasses.