In particular, he is credited with the discovery of phagocytes (macrophages) in 1882. This discovery turned out to be the major defence mechanism in innate immunity.[4] He and Paul Ehrlich were jointly awarded the 1908 Nobel Prize in Physiology or Medicine "in recognition of their work on immunity".[5] He is also credited by some sources with coining the term gerontology in 1903, for the emerging study of aging and longevity.[6][7] He established the concept of cell-mediated immunity, while Ehrlich that of humoral immunity. Their works are regarded as the foundation of the science of immunology.[8] In immunology, he is given an epithet the "father of natural immunity