It has been proposed in some recent publications that the cavitation damage rate decreases markedly in solids after long exposure to cavitation. It has also been proposed that this low rate of cavitation damage is the one with physical significance for the solid. These observations have been made with specimens oscillated sinusoidally in liquids by means of magnetostrictive devices. In the observations described here, it is shown by means of photographs of the cavitation cloud over such specimens that the reduced damage rate results from the very sparse bubble cloud which is formed over the deeply damaged surface. The change in the damage rate therefore has hydrodynamic origin and is not related to a change in the properties of the solid. X-ray analyses show also that the extent of the plastic deformation of a solid with very light damage is the same as for a solid with very heavy damage.