Ilya Illich Mechnikov (1845 - 1916), Russian zoologist and bacteriologist. He investigated intracellular
digestion;
formulated the
theory of phagocytosis (the ingestion and
destruction of cells, microorganisms, or other foreign
matter in the blood by cells capable of surrounding, engulfing and digesting
bacteria and viruses) and made microscopic
studies of diseases of the blood.