Death

DEATH, the irreversible cessation of the basic vital properties of an organism, namely its respiration, circulation, and metabolism. Death can be defined only through its relation to life. Giving life its most general definition as a process of metabolism (dissimilation and assimilation), death is likewise defined as the irreversible cessation of metabolism, which is followed immediately by the decomposition of protein substance. In Dialectics of Nature, Engels speaks thus of life and death: "Life and death. Already now that physiology is not considered scientific which does not regard death as an essential moment of life (note: Hegel, Enz. I, pp. 152, 153), which does not understand that the negation of life is essentially inherent in life itself, such that life is always thought in relation to its inevitable result, which is constantly contained within it in embryo—death. The dialectical conception of life reduces precisely to this. But whoever has once understood this, for him all talk about the immortality of the soul has lost its meaning forever. Death is either the decomposition of an organic body, leaving nothing behind it except the chemical components that formed its substance, or it leaves behind a vital principle, a soul, which survives all living organisms, and not only man. Thus, a simple clarification of the nature of life and death with the help of dialectics is sufficient here to finish off with ancient superstition. To live means to die" (Engels, Dialectics of Nature, Moscow-Leningrad, 1930, pp. 9, 10). Consequently, death is the natural and inevitable completion of life and concludes the chain of successive changes in the organism occurring throughout life (see Old age). Such "physiological" death, occurring independently of special external influences (diseases, trauma) and representing the natural end of existence, is also called death from senile decay. Upon the autopsy of very deep elderly individuals, one may often fail to find such changes in the organs as could explain the cause of death. Old age itself, in the totality of the changes it induces both in respect to the functional activity of the organism (weakness) and in the anatomical respect (atrophy, degeneration, sclerosis), already represents a disease befalling every individual who has reached a known age, and therefore it is a normal, physiological disease (Mühlmann). In contrast to death from external circumstances (diseases, trauma), death from senile decay is death from a change in the internal conditions of life, i.e., a change in the totality of metabolic processes forming life, in the process of the individual's development. Death from senile decay is the final phase of the organism's development (Lipschütz). There is no unity of views on the causes of the onset of death from old age. Some, like Weismann, believe that death is a consequence of the wear and tear of the organism, wherein only the germ cells, capable of dividing indefinitely and not dying, do not wear out in the organism. Others explain senile atrophy by poor cellular nutrition in connection with vascular sclerosis in old age (but obligatory senile vascular sclerosis is by no means an established fact). According to Metchnikoff, the cause of cell death during life depends on their poisoning by toxins originating from the large intestines. For details on the causes of senile fading, see Old age. The most favorable objects for studying the phenomena of death are unicellular organisms—protozoa. A unicellular organism functionally corresponds to a whole organism (Calkins), and in structural respects can be compared, conditionally of course, with an isolated cell of a multicellular organism. The composition of natural solutions in which unicellular organisms live (excluding parasites) can be changed at will, creating various conditions. Weismann, studying death in unicellular and multicellular organisms, came to the conclusion that "death, i.e., limited life span, is by no means an attribute inherent in all organisms. Protozoa are immortal in the sense that they do not have 'death' ensuing from internal causes." In unicellular organisms, individual life ends by division into two daughter cells, the latter grow and divide again, and so on. There is no room here for the formation of a corpse. And, according to Weismann, death is a phylogenetically much younger phenomenon than protists. It develops for the first time in multicellular organisms, where special cells differentiated themselves to serve the purposes of reproduction and guarantee the continuation of the species, while the "soma," the bodily cells, after the lapse of time become a corpse. Maupas, Calkins, and R. Hertwig in their experiments came to opposite results. Breeding various species of infusoria, they were able to establish changes both in appearance and in the behavior of the infusoria over a series of generations, and after 100 or 300 divisions the infusoria died. Calkins established that the changes appearing after a series of divisions lead to death, but can be overcome by conjugation, changes in temperature, food composition, etc. Thus, in contrast to Weismann, according to Maupas, Calkins, and Hertwig, death from "internal causes" exists in protozoa. After a certain number of divisions, protozoa fall into a state of "senile degeneration," "depression," or "physiological degeneration," i.e., they possess a specific life cycle terminated by the destruction of the individual if conjugation or one of the stimuli noted by Calkins does not intervene from the outside. Woodruff made a significant correction to the experiments of Maupas and Calkins. Isolating the daughter cells each time after division in fresh hay infusion and excluding conjugation, he bred about 4,500 generations of infusoria over 7 years, which showed no signs of "depression" even in the later generations. The phenomena of depression and subsequent death in Calkins's and other experiments, in the opinion of Woodruff and Lipschütz, are based on the influence of metabolic products excreted by the infusoria into the culture medium. Woodruff's experiments showed that death in protozoa is not physiological death from "senile decay," but is caused by pathological irritation provoked by the accumulation of metabolic products in the culture medium. Woodruff's experiments enabled many biologists, together with Weismann, to assert the presence of "potential immortality" in nature. Death, consequently, in their opinion, is not an essential moment of life, but always appears in one form or another as an accident. But the recognition of potential immortality proceeds from a metaphysical understanding of the phenomena of death. For proponents of this view, death always and for all living beings manifests under all conditions in one and the same unchanging form. Such a position ultimately leads to a point of view that denies development and the emergence of the new. The concept of "immortality" essentially requires the recognition of constant individuals that do not change in the course of reproduction, which in turn requires the denial of development, the recognition of the constancy of existence conditions, etc. Meanwhile, the recognition of the mutability of individuals and species is the cornerstone of evolutionary theory. If the concept of "potential immortality" is given a narrow, restrictive meaning, specifically that in the course of evolution unicellular organisms arose, one of the properties of which is division, and that these organisms under certain conditions can produce an infinite series of organisms, even then the concept of "potential immortality" is incorrect, because it proceeds from unscientific assumptions about a constant, cyclically repeating, unchanging circle of phenomena: the mother cell gives identical daughter cells, these in turn give completely identical new generations, and so on. Thus, an anti-evolutionary conception is essentially given, denying the development of organisms, in this case protozoa. The theory of "potential immortality" is closely linked with the idealistic theory of the eternity of life and essentially is also a scientific cover for the clerical teaching of the immortality of the soul, and so forth. The standpoint of "potential immortality" disarms in particular concrete biological research on the question of the development and death of organisms. On the contrary, Engels's thoughts that "to live means to die" are an effective instrument for investigating the development of the organism at all its stages (Aizupet, Isakov, Tokin). In humans, death from senile decay is a rare phenomenon. ⅓ of all people die before the age of 20, scarcely ⅕ reach 40 years, ⅚ reach 70 years, and up to 90 years barely ⅟₂% reach it. According to statistical data in France, 1 in 200,000 people reaches one hundred years of age, and in Greece 1 in 25,600. Calculations based on probability theory made by Pütter (1921) showed that one can expect one case of death per total number of deaths at: At 105 yrs, per 1.1 million deaths. At 111 yrs, per 110 million deaths. At 106 yrs, per 2.2 million deaths. At 112 yrs, per 283 million deaths. At 107 yrs, per 4.3 million deaths. At 113 yrs, per 850 million deaths. At 108 yrs, per 9.1 million deaths. At 114 yrs, per 2,340 million deaths. At 109 yrs, per 19.4 million deaths. At 115 yrs, per 6,650 million deaths. At 110 yrs, per 44 million deaths.

In humans, it is customary to distinguish: 1) natural death (from senile decay), 2) pathological death, caused by pathological processes in the organism (death from diseases), 3) violent death, caused by mechanical, thermal, chemical, and other influences on the organism, 4) sudden death (see). The question of the causes of death in its various forms has naturally been posed for a long time and to this day remains a subject of lively discussions. And if as late as the end of the 19th century certain changes in the organism (edema of the brain, lungs, cardiac defect, etc.) were accepted as the cause of death, then with the development of physiology and pathology the explanation of death by such "causes" could no longer satisfy the thinking physician. The old physicians distinguished three "gates of death": the brain, the lungs, and the heart. The analysis of various types of pathological death led Nothnagel to the proposition: "Man almost always dies from the heart." Apart from diseases of the heart itself, according to Nothnagel, this also occurs in diseases of the central nervous system, respiratory organs, kidneys, and in infectious diseases. Hemorrhages into the brain, head injuries, strong affects lead to paralysis of the central nodes of the cardiac nerves. In all infectious diseases, "local processes in individual organs and systems in the event of death may be of a completely different character, yet always precise clinical analysis teaches that here too death is caused in the end by the failure of the cardiac muscle, the structure of which is altered under the action of corresponding morbid poisons." But this does not mean that the heart has died in the proper sense of the word, and the fatal outcome followed from the fact that its musculature could not work properly, its contractions were irregular, or it was completely switched off along important pathways, so that the activity of the rest of the heart became impossible. The muscle fibers themselves for the most part can still be quite fully functional at this time. Kuliabko took the hearts of children who died from diphtheria, pneumonia, meningitis, enteritis, and, by passing warmed Locke's fluid through them, in the majority of cases obtained partial restoration of heart activity. In a certain number of cases, the matter may concern paralysis of the heart caused by changes in the nervous apparatus of the heart and in the brain, as can happen with injuries to the medulla oblongata. In this case, the cardiac muscle is completely intact, and primary significance should be ascribed to the damage to the central cardiac apparatuses. Mühlmann, studying 133 cases of pathological death, found sharply expressed pigmentary atrophy in the cells of the nucleus of the vagus nerve and holds the opinion that in all cases, strictly speaking, there was death from the nerve centers for the heart. According to Schorr, "paralysis of the heart in the modern understanding represents a regular phenomenon for all those dying a natural or premature death, as the final chord of life, but its development depends on an infinite number of conditions." Paralysis of the respiratory center can also in a number of cases be the cause of death. This kind of death is observed in poisoning by certain poisons possessing a selective action on the central nervous system (morphine, cocaine, atropine); chloroform in individual cases also leads to death from paralysis of the respiratory center. This type of death can also be caused by mechanical moments, for example, closure of the respiratory tracts (in cases where death does not occur immediately from reflex cardiac arrest), spasm of the respiratory musculature (in tetanus). Paralysis of the respiratory center can also lead to the inability of the blood to absorb and transport oxygen, as happens in carbon monoxide poisoning. But cessation of respiration and paralysis of the respiratory center in themselves are not yet death. The final word still rests with the heart, since only from the moment of cardiac arrest can one speak of the death of the individual. A convincing proof of this is the return to life by artificial respiration of the drowned or numerous examples from surgical practice of respiratory paralysis on the operating table during anesthesia. Ultimately, the moment of onset of death is the cessation of cardiac activity, but the interests of health statistics and record-keeping naturally cannot be satisfied by indicating such causes of death as paralysis of the heart or respiration. This circumstance led to the necessity of developing a classification and nomenclature of the causes of death. There is an international classification and nomenclature of the causes of death and diseases, and in 1924 the People's Commissariat of Health of the RSFSR approved it for use in the republic (see Mortality). This nomenclature encompasses not so much the causes of death in the proper sense of the word, but those or other main diseases which in one way or another led to death, without being themselves its cause. Thus, by registering death from appendicitis, arteriosclerosis, etc., health statistics register the underlying diseases. As for the causes of death in these cases, they can be very diverse: in appendicitis, death may occur in connection with peritonitis, causing cardiac paralysis; in arteriosclerosis, in connection with hemorrhage into the brain leading to respiratory paralysis, and so on. In other words, official health statistics are not statistics of the causes of death in the direct or immediate sense of the word, but statistics of the underlying diseases, constructed on a nosological principle. A similar differentiation (into the underlying disease and the cause of death) is also made at post-mortem autopsies, indicating (especially German authors) separately the main disease (Hauptkrankheit) and the cause of death (Todesursache). From what has been said, it follows that the concept of disease (leading to death) and the cause of death itself (in the same disease) are different things, each time subject to special clinical and pathoanatomical analysis. Violent death, which we encounter in murders, suicides, executions, accidents, does not differ in its mechanisms from those in pathological death. In the majority of cases, even in violent death, it is possible to establish as the cause of death paralysis of the respiratory center or paralysis of the heart. Violent death is subject to the consideration of forensic physicians, and in their practice the immediate moments that entail paralysis of respiration or the heart are usually accepted as the cause of death. In some cases, upon the destruction or extensive devastation of organs vital to life, precisely these damages are accepted as the cause of death without explaining them in a strictly physiological sense, e.g., ruptures of the heart, destruction of the medulla oblongata. Further, causes of violent death include shock and bleeding, which essentially is death from oxygen starvation, i.e., asphyxia, and so on. In all such cases, they speak of the immediate cause of death. The immediate cause of death cannot always be established at autopsy. Sometimes it can be established only on the basis of anamnesis (e.g., shock). If there are several injuries, each of which could have been fatal in itself, or if autopsy establishes the possibility of other types of violence (hanging, strangulation), then in such cases they speak of the coexistence or competition of causes of death. Sudden death can be caused by pathological processes present in the organism, the ascertainment of which at autopsy leaves no doubt about the mechanism of the onset of death, e.g., hemorrhages into the brain of an arteriosclerotic nature, ruptures of aneurysms of large vessels, ruptures of the heart, and others. In those cases of sudden death where changes are ascertained at autopsy that cannot in themselves explain the cause of death, the main role in the pathogenesis of sudden death is assigned to the heart, by the sudden arrest of which death is explained. In some cases, the heart presents no changes and its arrest can be caused by a reflex from various organs—the larynx, testicles, uterus (essentially there is no organ from which a reflex on the heart could not be caused). In other cases, the heart itself presents certain changes in its various parts, and cardiac paralysis is often caused by a sudden increase in the demand for its work—physical exertion, psychic affects. The onset of "clinical" death does not yet mean that a complete cardiac arrest has occurred. Research by a number of authors has shown that after the onset of clinical death, the heart can still beat for another 3–5 minutes and various parts of the heart cease to contract at different times. The heart dies piecemeal. However, the cessation of respiration and even cardiac arrest are not synonymous with the death of the body as a whole. Kuliabko's experiments with surviving hearts, Kravkov's experiments with isolated organs, cultures of tissues taken from a corpse, all this indicates that individual organs survive the general death of the organism for a long time. An exceptional example of tissue resilience is the experiments of P. I. Bakhmetiev with the freezing of bats (see Anabiosis). All these data on the survival of individual organs and tissues involuntarily raise the question of the possible reversibility of the death process in individual cases. During the life of the organism, individual organs, parts of them, and areas of tissue can undergo dying, which is designated as local death, necrosis (see). The death of the organism is accompanied by the appearance of so-called "signs of death."

The cessation of blood circulation leads to the pooling of blood in dependent parts of the body, causing the skin to turn pale, the appearance of postmortem hypostases, a drop in body temperature, and the development of rigor mortis (see Death).