  Evidence of small-scale condensations in the magnetic molecular clouds has
been accumulating over the past decades through radio and optical/ultraviolet
observations. The origin and shape of these small-scale condensations is a
disputable issue. Nejad-Asghar & Ghanbari (2004 hereafter NG) have recently
studied the effect of the linear thermal instability on the formation of
fluctuations in molecular clouds. The authors inferred that under certain
conditions (e.g., depending on expansion or contraction of the background)
thermal instability and ambipolar diffusion can produce spherical, oblate, or
prolate condensations.
