EN
Influence of such factors as temperature, pH, CO₂ level and oxidationreduktion potential value in the alimentary tract of host on the stimulation of invasive eggs was studied. Changes of these factors lead to change in permeability of inner layer of egg-shell. Then the hatching fluid is released and its enzymes digest the egg-shell. In the nematodes, which have the free-living larvae, the initiation process can depend on parasite or environmental agents.