  It is shown that the Euler system of hydrodynamic equations for inviscid
barotropic fluid for density and velocity is not a complete system of dynamic
equations for the inviscicd barotropic fluid. It is only a closed subsystem of
four dynamic equation. The complete system of dynamic equation consists of
seven dynamic equations for seven dependent variables: density, velocity and
labeling (Lagrangian coordinates, considered as dependent variables). Solution
of the Cauchy problem for the Euler subsystem is unique. Solution of the Cauchy
problem for the complete hydrodynamic system, containing seven equations, is
unique only for irrotational flows. For vortical flows solution of the Cauchy
problem is not unique. The reason of the nonuniqueness is an interfusion, which
cannot be taken into account properly in the framework of hydrodynamics. There
are some arguments in favour of connection between interfusion and turbulence.
