DECAY AND DEATH. 1001 



vulsive movements are performed. In the third stage, all outward and 

 respiratory movements have ceased, but the heart still beats. In an 

 asphyxiated animal, the heart will beat for seven minutes, or three 

 minutes after the arrest of external movements. 



In coma, death begins at the brain, the sensorial functions being 

 those which are first suspended. This mode of death occurs in fevers, 

 in certain diseases of the brain, and in injuries of this organ, when 

 these do not kill by shock or concussion. Thus, a person may receive 

 a violent blow on the head, giving rise to symptoms of syncope ; and 

 after a time, although the heart regains its power, and respiration and 

 circulation still continue, a state of profound stupor sets in, and death 

 occurs in a comatose condition. Narcotic poisons, such as opium, bel- 

 ladonna, and chloroform, also produce death by inducing coma. 



Death, however, frequently occurs in all these three modes. Thus, 

 pressure on the brain, may not only induce coma, but also asphyxia 

 and syncope, by paralyzing the medulla oblongata, from which the 

 pneumogastric nerves, supplying the heart and lungs, arise. The fatal 

 effects of chloroform, on the other hand, may depend on asphyxia, 

 coma, or cardiac syncope. 



Death from old age, or the gradual decay of nature, the natural 

 mode of dying, is much less common than death from unnatural causes. 

 Towards the decline of life, the formative power becomes defective ; 

 the processes of nutrition, growth, and development of the tissue-ele- 

 ments, no longer keep pace with the individual waste and death of 

 these ; so that the various organs of the body suffer a marked and 

 gradually increasing structural deterioration or degeneration, and their 

 functional powers are consequently diminished. These deteriorations 

 or degenerations constitute senile atrophy, and are as natural and 

 normal to the living organism as nutrition itself. The body either 

 wastes and dries, or it grows fat, the individual either becoming ema- 

 ciated or else corpulent. The coats of the arteries undergo fatty 

 changes, the cornea exhibits the arcus senilis, and there is an increased 

 quantity of fat in all the tissues and organs. The arteries become the 

 seat of calcareous deposits, the bones contain an increased quantity 

 of earthy salts, and the cartilages undergo ossification. The walls of 

 the bloodvessels and other structures become thickened ; the mucous 

 membrane of the alimentary canal frequently presents an ash-colored 

 appearance, and the lungs, even early, exhibit deposits of black pig- 

 ment. Lastly, if disease or injury in no way interferes with the ordi- 

 nary duration of life, the activity of all the functions slowly diminishes, 

 until the vitality of the entire organism gradually becomes extinct. 



The ordinary external appearances which indicate death, are, the 

 cessation of breathing, the absence of pulse, a half-closed state of the 

 eyelids with dilatation of the pupils, clenching of the jaws with slight 

 protrusion of the tongue, and partial contraction of the fingers. The 

 skin is cold and pale, or, if livid, is becoming paler. After a few days, 

 a deceptive increase of color of the skin is sometimes noticed, owing to 

 the blood being forced, by the evolution of gases from the larger cen- 

 tral vessels, into the small vessels of the skin. 



The only positive signs of actual death are those which depend on 



