  In order to search for intensity fluctuations on the HCN(1--0) and
HCO$^+$(1--0) line profiles which could arise due to possible small-scale
inhomogeneous structure long-time observations of the S140 and S199 high-mass
star-forming cores were carried out. The data were processed by the Fourier
filtering method. Line temperature fluctuations that exceed noise level were
detected. Assuming the cores consist of a large number of randomly moving small
thermal fragments a total number of fragments is $\sim 4\cdot 10^6$ for the
region with linear size $\sim 0.1$~pc in S140 and $\sim 10^6$ for the region
with linear size $\sim 0.3$~pc in S199. Physical parameters of fragments in
S140 were obtained from detailed modeling of the HCN emission in a framework of
the clumpy cloud model.
