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 .