  The similarity theory of stellar structure is used to study the properties of
very massive stars when one can neglect all the sources of opacity except for
the Thomson scattering. The dimensionless internal structure of such stars is
practically independent of the energy generation law.
  It is shown that the mass-luminosity relation can be approximated by an
analytical expression which is virtually universal regarding the chemical
composition and energy generation law. A detailed comparison with the
  Eddington standard model is given. The application of the obtained results to
the observations of massive stars is briefly discussed.
