To these forms of dying may be added (according to Dr. C. J. B. Williams) neertemia. or D. beginning in the blood, such as occurs in typhoid fevers and in other diseases of a malignant or pestilential kind. In this case, there is complete and general prostration of all the living powers. The blood, the natural source of life to the whole body, is itself dead, and spreads death instead of life. Almost simultaneously, the heart loses its power; the vessels, and especially the capillaries, lose their tone, and congestion takes place in various organs; the medulla oblongata, from which the chief respiratory nerves arise, is torpid; the powers of respiration fail; voluntary motion is almost sus pended; molecular nutrition ceases, and is very rapidly followed by general molecular D.; that is to say, structures and even organs die, and begin to undergo decomposition as soon as the pulse and breath have ceased; and indeed, a partial change of this kind may even precede somatic D., as, for example, when parts become gangrenous, etc.
The signs of approaching D. require a brief notice. The mind may be affected in various ways; there may be dullness of the senses, vacancy of the intellect, and extinc tion of the sentiments, as in natural D. from old age; or there may be a peculiar delirium, closely resembling dreaming, which usually is of a pleasing and cheerful char acter.
Saw ye not even now a blessed troop Invite me to a banquet, whose bright faces Cast thousand beams upon me like the sun? King Henry VIM, Act iv Scene 2.
In dreadful contrast with such visions, are those which haunt the dying minds of others, when it would sometimes almost appear as if the sinner's retribution commenced even on his death-bed.
Dementia or imbecility sometimes comes on shortly before D., 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. The great dramatist from whom we have just quoted, 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 D. approaches, often dwindling to a mere whisper. The mode in which the action of the heart declines is various; in most dis eases 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,,fespiratien is sometimes hurried and panting till just before D., while in other cases it is slow, laborious, and stertorous. The accumulation of mucus, etc., 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 col lected in the trachea and upper respiratory passages.
There is a loss of animal heat, beginning at the extremities. For further informa tion on this subject, we may refer to the article DEATH in The Cyclopfedia of Anatomy and Physiology, from which we have borrowed some of the matter of the preceding paragraphs.
The signs of actual D. 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 D.; but these functions, as in the case of hybernating 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, these functions are frequently suspended and again restored; and cases like,that of co'). Townsend (see any standard work on medical jurisprudence) occasionally occur, in which the patient has the power of suspending these functions for a considerable period.
The loss of irritability in the muscular fibers (a fact which may readily he ascertained by a galvanic current) is a sign of fax greater importance than either the apparent stop. page of the circulation or of the respiration. 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 wouud 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 D., is the most important. It may appear within half an hour after D., or may be delayed 20 or 30 hours, according to the nature of the disease; and its mean duration is from 24 to 36 hours. It commences in the neck and trunk, then appears in the lower, and lastly in the upper extremities, and disappears in the same oilier.
3. Various changes in the external appearance of the .body have been regarded as indicative of D. by different writers; of these, time most important unquestionably is the altered color of the'surface. -Livid spots of various sizes may occur from local con gestions 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 D. is obviously not a matte •of mere physi ological 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 abbii 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 of the last century, 13ruhier, in a work On the .Danger of Premature Interment, collected 54 cases of persons buried alive, 4 of persons dissected while still living. 53 of persons who recovered without assistance after they were laid in their coffins, and 72 falsely considered dead.