Observations of the structure of winds in WR+O binaries

Results of recent investigations of interacting stellar wind regions and proper, nondisturbed WR winds in WR+O binary systems are summarized. The results of our investigations have shown that the motion of the material in the photospheric part of the WR wind in the V444 Cyg system (tau(e) = 0.0 - 0.7) is accelerated. If the acceleration is expressed in terms of Lamers' beta-law, the corresponding value of beta ranges from similar to 1.1 to similar to 2.3, i.e. the acceleration varies from moderate to slow. Due to clumping structure of the WR wind we can neglect the effect of decreasing of masses of WR stars during their evolution. Distribution of the masses of WR stars is continuous but not bimodal as distribution of masses of neutron stars and black holes in binary systems.