Immortality

Immortality, a conditional biological term for denoting the continuous succession of life phenomena in the series of generations of living organisms. The boundaries of this continuity, and therefore of immortality in the indicated sense, are determined, however, by the presence of certain cosmic conditions under which they can be considered theoretically continuous. In this sense, biology also uses the term potential immortality. The death of humans, animals, and plants is such a common and constant phenomenon that it is considered the inevitable end of all life. However, the phenomena of regeneration show that, unlike other machines, an organism has the ability to heal and restore lost parts. On the other hand, life as a whole is characterized precisely by its continuity and succession over many millions of years, i.e., conditional immortality. From this point of view, in the problem of I., the most mysterious fact is the emergence of the individual death of organisms. For the first time, Weismann expressed the view that lower organisms do not know natural death (are immortal). Unicellular organisms reproduce by division, during which the maternal individual breaks down into two or more daughter individuals and no corpse remains. The French zoologist Maupas (1888) attempted to refute this statement and conducted experiments showing that when reproducing by division, unicellular organisms (infusoria) wear out and become extinct after several dozen or hundreds of generations, and only the sexual process (conjugation) restores their vitality and reproductive capacity. Further experimental research showed the incorrectness of Maupas's conclusions: in his experiments, infusoria died not as a result of the absence of the sexual process, but because they were poisoned by nutrient media that were not changed frequently enough. Zhukovsky, Woodruff, Metchnikoff and others, who paid attention to the careful preparation and changing of nutrient solutions, observed no degeneration or extinction of infusoria during many thousands of generations (more than 20 years) when reproducing by division without the sexual process. Thus, potential immortality for unicellular organisms can be considered experimentally proven within the limits of the indicated experiments. True, the research of Woodruff and Erdmann discovered in infusoria reproducing without the sexual process a periodic reorganization of the nuclear apparatus, during which part of the nucleus perishes. But a similar destruction of certain parts of the cell or entire cells continuously occurs in any organism during its life and has little in common with the phenomenon of death. At present, the existence of the same potential I. can be extended to a number of higher multicellular organisms. It has been experimentally proven that hydra and some worms can reproduce, apparently indefinitely, by division, during which no corpses remain. Many trees, such as sequoias, oaks, baobabs, live for thousands of years without showing any signs of degeneration, and perish not by natural death, but from accidental causes (fire, storm, or human intervention). Corals apparently also possess such potential I.; their death is caused only by a rise or fall in the level of water in the ocean. Parallel to his teaching on the I. of unicellular organisms, Weismann expressed the theory of potential I. of the germ (sexual) cells of multicellular animals and plants. Of course, millions of spermatozoa perish because they do not have the opportunity to meet an egg. But with respect to each egg or spermatozoon, one can say with certainty that none of its ancestral cells, the infinite series of which extends back into geological periods, died a natural death and left behind a corpse. During the development of an organism from an egg, differentiation occurs into potentially immortal sexual cells and into the body, which in higher animals and most plants is doomed to natural death after a certain period determined by species characteristics. According to Weismann, the individual death of the body arose, like any other adaptation, as a result of natural selection in the process of the struggle for existence between species. For this reason, species that are too long-lived, such as large trees and probably fossil giant reptiles, cannot evolve quickly and adapt hereditarily to changing conditions due to the rare change of generations, and therefore they become extinct when conditions change sharply. Conversely, in annual plants and insects, the change of generations occurs very quickly, and therefore their hereditary variability is high. These groups and similar ones are richest in species and fill all corners of the earth's surface where life can exist. The causes of natural aging and death have not yet been clarified. Apparently, this is some kind of self-poisoning of the organism, the time of which is determined by species characteristics as well as external conditions. It is very probable that through artificial intervention this self-poisoning can be weakened, and perhaps even completely eliminated (see Rejuvenation). A substantial basis for such an assumption is the fact that, according to recent exact experimental data, many cells of a mortal organism are potentially immortal under special conditions. By means of the method of tissue culture outside the organism, with sufficiently frequent changing of nutrient solutions, it has been proven that under suitable conditions some tissue cells can live and reproduce in an artificial environment for a much longer period than the duration of their life within the corresponding organism—theoretically indefinitely. To what extent such potential I. extends to all tissue cells (including nerve cells) and by what means it is possible to ensure for them a constant change of nutrient medium within the organism, removing from the body the self-poisoning toxins of senility—this question requires further scientific investigation.