In order to investigate the effect of solid impurities on cavitation, the distribution functions of nuclei were studied in water samples that had various impurities and were differently treated: filtered, placed under a lead screen, de‐ionized, or with addition of uranyl nitrate. We have used two kinds of impurities : wettable particles (emery and corundum) and unwettable particles (Teflon). Although the results give support to Harvey's stabilization theory, the action of impurities is not simply a stabilizing one; the impurities play an active role in determining the shape of the distribution functions. The unwettable impurities cause a production of large‐size nuclei, while the wettable ones destroy large nuclei and increase the concentration of small nuclei. A phenomenological treatment of the mentioned effect is suggested.