Disease is not the prerogative of man and the domestic animals, so it was quite natural to see if the lower animals, with very simple organizations, showed pathological phenomena, and if so, infection, cure and immunity could be observed among them. Elie Metchnikoff More Quotes by Elie Metchnikoff More Quotes From Elie Metchnikoff There is only one constant element in immunity, whether innate or acquired, and that is phagocytosis. The extension and importance of this factor can no longer be denied. Elie Metchnikoff importance constant elements Needless fear and panic over disease and misfortune that seldom materialize are simply bad habits. By proper ventilation and illumination of the mind it is possible to cultivate tolerance, poise and real courage. Elie Metchnikoff illumination real fear It is possible to state as a general principle that the mesodermic phagocytes, which originally (as in the sponges of our days) acted as digestive cells, retained their role to absorb the dead or weakened parts of the organism as much as different foreign intruders. Elie Metchnikoff cells principles science In the same way that plants will not grow on soil that lacks some substance indispensable to their growth, so microbes, these microscopic plants which cause infectious disease, are unable to grow in an organism which does not give them all the substances they need. Elie Metchnikoff growth giving way It is often seen that in households where all members are exposed to the same danger, or again in schools or troops where everyone lives the same life, disease does not strike everyone indifferently. Elie Metchnikoff strike everyone disease life The appearance of aged persons is too well known to make detailed description necessary. The skin of the face is dry and wrinkled and generally pale. The hairs on the head and the body are white. The back is bent, and the gait is slow and laborious, whilst the memory is weak. Such are the most familiar traits of old age. Elie Metchnikoff face memory old-age age Inflammation as understood in man and the higher animals is a phenomenon that almost always results from the intervention of some pathogenic microbe. Elie Metchnikoff animals man always results Whatever concerns health is of real public interest. Elie Metchnikoff whatever interest health real It is, of course, quite natural that a biologist whose attention had been aroused by noticing in his own case the phenomena of precocious old age should turn to study the causes of it. Elie Metchnikoff own old-age age attention Science, it is said, no doubt has ameliorated the material conditions of human life, but is powerless to solve those moral and philosophical questions that interest cultured people so deeply. Elie Metchnikoff doubt life science people In the ancient world and, above all, among the Greeks, human nature was held in high esteem. Elie Metchnikoff high human-nature nature world The adoration of human nature by the Greeks appeared in Greek plastic art and was the cause of its excellence. Elie Metchnikoff plastic excellence nature art The Greek conception of a life in harmony with nature found its most complete development in the rationalism of the Renaissance and of the centuries that followed it. Elie Metchnikoff harmony development nature life Most of the centenarians whom I have been able to see have been so defective mentally that all that can be studied in them are the physical qualities and functions. Elie Metchnikoff them physical been see The old age of lower mammals presents characters similar to those found in man. Elie Metchnikoff old man old-age age
