Death. It is one of the fundamental doctrines of physiology, that every part of the organism has its own definite term of vitality, and that there is a continuous succession of the destruction of old cells and the formation of new ones in all tissues, and especially in those in which the most active vital changes are going on, as, for example, in the nervous and muscular tissues. Even the most solid portions of the animal frame, such as the bones and (to a less extent) the teeth are undergoing a perpetual although a slower change of this nature; and throughout the whole body there is a continuous removal of effete or worn-out tissues, and a corresponding deposition of new matter. Every blow we strike, every thought we think, is accompanied by the death and disintegration of a certain amount of muscular or nervous tissue as its necessary condition; and thus every action of our corporeal life, from its beginning to its close, takes place at the expense of the vitality of a certain amount of organised structure. This is termed molecular death, and, within its proper limits, is obviously essential to the life and well-being of the organism.
The cessation of the circulation and respiration may be regarded as constituting somatic death, or the death of the entire organism, which must obviously be shortly followed by the molecular death of every portion of the body.
We shall now briefly notice the principal modes in which death occurs. Death happens either from the natural decay of the organism, as in old age, or (and much more frequently) from some of those derangements or lesions of the vital organs which occur in the course of the diseases and injuries to which we are liable. These derangements of the vital organs may occasion various modes of dying. Dr Watson said that life rests on a tripod, whose three vital supports are the heart, the brain, and the lungs; and Bichat, that 'the mode of dying may begin at the head, the heart, or the lungs.' The functions of these organs are, however, so mutually dependent upon each other, that impairment in the functions of one of them may lead to death, though the immediate cause of death is the failure of another.
Death from failure of heart may be either sudden or gradual. Sudden failure (death by syncope or fainting) may occur from disease or weakness of the heart itself, or from shock conveyed to it through the nerves. Gradual failure takes place when the whole system is enfeebled—e.g. by the action of certain poisons, and by many wasting diseases (death by asthenia, Gr., 'want of power'). When death occurs from loss of blood (anæmia), the failure of the heart may be either sudden or gradual, according to the extent of the loss; but in this case the heart ceases to contract not from inability to do so, but because the blood, its natural stimulus, is insufficient in amount to excite contraction.
Death from failure of respiration (Asphyxia, q.v.) occurs when access of the air to the lungs is impeded, or when the actions of the muscles of respiration cease. We have examples of it in drowning, smothering, choking, strangulation, &c. Forceful pressure upon the chest, such as sometimes happens in great crowds, or as occurs to workmen partially buried by the fall of earth, &c., will cause death in a few minutes, if movement of the lungs is prevented by the pressure. Tetanus and the poison of strychnine prove fatal in this way.
Death by coma, or beginning at the brain, is caused by obstruction to the circulation through that organ by pressure (as, for example, when there is effused blood within the cranium, or when a portion of bone is depressed in a fractured skull); by clots of blood within the vessels; by various narcotic poisons, such as opium, alcohol in excessive quantity, carbonic acid, &c.
To these forms of dying some writers propose to add necremia, or death beginning in the blood, as in typhoid fevers and in other diseases of a malignant or pestilential kind. Such cases may, however, always be referred to one of the three forms already enumerated, or a combination of them; and further complication seems unnecessary.
The signs of approaching death require a brief notice. The mind may be affected in various ways; there may be dullness of the senses, vacancy of the intellect, and extinction of the sentiments, as in natural death from old age; or there may be a peculiar delirium, closely resembling dreaming, which usually is of a pleasing and cheerful character.
Dementia or imbecility sometimes comes on shortly before death, and manifests itself by an incapacity of concentrating the ideas upon any one subject, and by an almost total failure of memory. The mental weakness is often exhibited by the pleasure which is derived from puerile amusements. Shakespeare notices 'playing with flowers' as a token of approaching dissolution. In the form of delirium, ocular spectra seem frequently to be present, the patient apparently trying to catch some imaginary object.
There is generally well-marked relaxation and incapacity of the muscular system, and the voice is usually weak and low as death approaches, often dwindling to a mere whisper. The mode in which the action of the heart declines is various; in most diseases of long standing, the cessation of the heart's action is gradual, the rate of the pulsations being much increased, but their energy being very much impaired. In some acute affections, the failure is shown by the irregularity of the pulse, while the force is little altered. In other cases (especially in cerebral diseases) the heart, before finally ceasing to beat, contracts violently, and suddenly stops.
The respiration is sometimes hurried and panting till just before death, while in other cases it is slow, laborious, and stertorous. The accumulation of mucus, &c. in the air-passages increases the difficulty of breathing; the sound known as the 'death-rattle' being produced by the passage of the air from the lungs through the fluid collected in the trachea and upper respiratory passages. There is also a loss of animal heat, beginning at the extremities.
The signs of actual death may be arranged under three heads: (1) Signs of the extinction of the vital functions; (2) Changes in the tissues; (3) Changes in the external appearance of the body.
(1) The arrest of the circulation and respiration would at first sight appear to afford decisive evidence of death; but these functions, as in the case of hibernating animals, may be reduced to so low a condition that it is by no means easy to decide whether or not they are completely annihilated. In cases of apparent drowning, and in newly-born infants, these functions are frequently suspended and again restored; and cases like that of Colonel Townsend (see any standard work on medical jurisprudence) occasionally occur, in which the patient has the power of voluntarily suspending these functions for a considerable period. The gradual loss of animal heat is an important sign. But it is sometimes delayed; and in exceptional cases a rise of temperature may even take place after death. Loss of contractility of the muscles when a galvanic current is applied to them is a certain sign of death; but the period at which it takes place is very variable. The contractility of the skin is also lost after death. When a cut is made through the skin of a dead body, the edges of the wound collapse, while a similar lesion inflicted during life presents an open or gaping appearance.
(2) Among the changes in the tissues, the rigor mortis, or rigidity of the muscles, which ensues at a varying period after death, is the most important. It may appear within half an hour after death, or may be delayed twenty or thirty hours, according to the nature of the disease; and its mean duration is from twenty-four to thirty-six hours. It commences in the neck and trunk, then appears, according to most observers, in the upper, and lastly in the lower extremities, and disappears in the same order.
(3) Various changes in the external appearance of the body have been regarded as indicative of death by different writers; of these, the most important unquestionably is the altered colour of the surface. Livid spots of various sizes may occur from local congestions during life; but the appearance of a green tint on the skin of the abdomen, accompanied by a separation of the epidermis, is a certain sign that life is extinct.
The discrimination of true from apparent death is obviously not a matter of mere physiological interest. The case of Vesalius, the eminent anatomist, who opened an apparently dead body in which the exposed heart was seen to be still beating, is well known; as also that of the Abbé Prevost, who, having been struck down by apoplexy, was regarded as dead, but recovered his consciousness under the scalpel, and died immediately afterwards; and a French author, Brulier, in a work On the Danger of Premature Interment (1742-45), collected fifty-four cases of persons buried alive, four of persons dissected while still living, fifty-three of persons who recovered without assistance after they were laid in their coffins, and seventy-two falsely considered dead. But when reasonable care is taken such mistakes are hardly possible. See BURIAL, CATALEPSY.
Death, in a legal point of view, is either natural or civil: the former being the cessation both of physical life and of the legal rights which attach to it; the latter, the cessation of the legal rights whilst the physical life remains. A man was said to be civilly dead in England when he had been attainted of treason or felony, or had abjured the realm, or was banished, or became professed in religion by going into a monastery. In these events his property devolved as if he were naturally dead. The doctrine of civil death is now abolished except as to cases of outlawry, in which it seems still to be applicable.
According to the Scottish Law of Death-bed, an heir in heritage was entitled to reduce all voluntary deeds granted by his ancestor to his prejudice, if they were granted by this ancestor on his death-bed. It was necessary that at the time the deed was granted the ancestor should be suffering from the disease of which he died, and should not survive for more than sixty days. The law did not apply if, after granting the deed, the ancestor was able to go unsupported to kirk or market. The law of death-bed was abolished in 1871.
The so-called Valley of Death is a specially arid tract in the MOHAVE DESERT (q.v.)—a depression without vegetation, and with a saline efflorescence. See also the articles ANNUITY, CAPITAL PUNISHMENT, DANCE OF DEATH, DISEASE, EXECUTION, INSURANCE, LIFE, REGISTRATION.