The phenomena of adaptation, observed on cave-dwelling organisms, fitting themselves to the particular conditions of the caves, must not be explained in lamarckistish sense. They are phenomena of general organical reductions. As primary inducements, they compel some species, which have been made helpless in consequence of happening reductions to retire themselves spontaneously in caves. Trogloditism is therefore no cause of the peculiar decay of notorious cave-dwellers, on the contrary, it is the last stage of incessant phenomena, induced by reductions (results). The reductions arise independently from the cave, the cave is only a fitting place of existence, in which the decaying organisms introduced themselves afterwards.