The disturbance created by a source producing sound in a medium travels through:
A particle of the medium in contact with the vibrating object is displaced from its equilibrium position. This particle then exerts a force on the particle adjacent to it and displaces the particle from its position of the rest. The first particle then again comes back to its position of equilibrium. So there is no permanent displacement of the particles. Hence the disturbance created by source travels through the medium and not the particles of the medium.