The critical load required to form a hertzian fracture in sliding is markedly influenced by the liquid environment in which sliding takes place. The presence of an active environment (water and phosphoric acid) reduces the critical load by 65 to 70%, while the presence of a less-active environment (liquid paraffin) reduces the friction and increases the critical load. It is shown that the critical load in some environments can be predicted in agreement with experimental results provided that the critical load in a certain environment is known.