A century of science after I. Metchnikoff’s death demonstrated the truth in many of his views and judgments in the field of immunology, pathology, bacteriology, zoology and comparative embryology. Today Metchnikoff is deservedly called the father of the theory of cellular immunity, and also a harbinger of the theory of natural immunity. His work in the field of lactic acid bacteria formed the basis for an entire industry of probiotics. Metchnikoff’s doctrine of the possibility of extending human life is still relevant. This publication is one more attempt to tie the biography of the scientist with his creative legacy and his contribution in the world treasury of biological science.