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CADAVERIC RIGIDITY, OR RIGOR MORTIS.

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the first three hours after death to be at the rate of about 4° F. per hour, during the next six hours the rate was 3° per hour; and, at later periods, rather more than 1° per hour. Burman found the average rate of cooling during the first eight hours after death to be 2° F. per hour: Ed. Med. and Surg. Jour., 1880, p. 993.

3. Cadaveric Rigidity. Rigor Mortis.-In from three or four to five or six hours after death, and generally while the body is in the act of cooling, the muscles of the limbs are observed to become hard and contracted in the attitude in which the body is placed; the joints are stiff, and the trunk firm and unyielding. This peculiar condition is known under the name of cadaveric rigidity, or rigor mortis. The first effect of death from any cause is in most cases a general relaxation of the whole of the muscular system. The lower jaw drops, the eyelids lose their tension, the limbs are soft and flabby, and the joints are flexible. The muscular tissue may be considered as passing through three stages in a dead body. 1. It is at first flaccid, but contractile; although, it may be remarked, that muscles contracted by living force in the act of dying do not necessarily become relaxed in death. 2. It becomes rigid and incapable of contraction. 3. It is once more relaxed, and does not regain its power and contractility. The body now passes into the state of incipient putrefaction. The first stage defines the duration of muscular irritability; the second stage, that of cadaveric rigidity; and the third, that of the commencement of chemical changes, or putrefaction.

At a certain period after death, the heart is found rigid and firmly contracted. If examined at this time, it may appear to be in a state of spasm, and to have its walls thickened, while the cavity of the left ventricle may be described as being much smaller than in the normal state. J. Paget has pointed out that this natural condition of the heart after death has led to pathological mistakes, the walls being described as thickened, the cavities diminished in size, and the heart itself as being in a state of concentric hypertrophy from disease. On the other hand, the perfect relaxation of the heart which follows at a later period after death has been mistaken for, and described as, a morbid flabbiness and flaccidity. Spasm and paralysis cannot be inferred to have necessarily existed during life when we discover these conditions of the heart in the recently dead body. ["Besides these external causes, Prof. Reese says there are others subjective or inherent in the body, such as age, sex, state of the body, manner of death, influence of disease, etc.

"Aged bodies decompose slowly, probably on account of their comparative want of moisture; while the bodies of new-born children rapidly putrefy for the opposite reason. Fat and flabby bodies undergo decomposition more rapidly than lean ones, because they contain more fluids; the same is said to be true of the bodies of women dying in childbed. In cases of very sudden death in persons of previously sound health, putrefaction is more rapid than when it has resulted from an exhausting disease. When the blood has been impoverished, as in typhus, and when the body has previously been much contused (provided it has not been protected from the influence of the air, as when buried under rubbish), the process of decomposition is accelerated.

"It is also rapid after death from suffocation by smoke, coal gas, or sulphuretted hydrogen; also by strangulation, draining and asphyxia generally; also after narcotic poisoning; but it is slower after death from phosphorus, alcohol, sulphuric acid, and arsenic.

The order of decomposition of the internal organs, according to Caspar, is as follows: Trachea and larynx, brain of young infants, stomach and

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intestines, spleen, omentum and mesentery, liver, brain of adults, heart and lungs, kidney, bladder and oesophagus, pancreas, diaphragm, large vessels (especially the arteries), and, last of all, the uterus."]

Under the action of poisons like strychnine and those other alkaloids which cause death by convulsions, the more violent and frequent the convulsions, the sooner rigidity sets in. Whatever exhausts muscular irritability before death, appears to accelerate rigor mortis in the muscles after death. In those instances in which muscular irritability at the time of death is slight, either in consequence of a bad state of nutrition or of exhaustion from over-exertion, or from convulsions caused by disease or poison, it is observed that rigidity sets in and ceases soon, and putrefaction appears and progresses quickly: Brown-Séquard, Proc. Roy. Soc., 1861, p. 204. For a similar reason it takes place at an earlier period in the very young and in the old, than in an adult in the prime of life.

If we allow a proper interval to elapse after the supposed death of a person, there can be no difficulty in solving the question whether the body is really dead even before any of those changes which arise from putrefaction have manifested themselves. The circumstances on which we may rely as furnishing conclusive evidence of death are the following: 1. The absence of circulation and respiration for at least an hour, the stethoscope being employed. 2. The gradual cooling of the body approximately to the temperature of the air, the trunk remaining warm while the members are cold. 3. As the body cools, the gradual supervention of a rigid state of the muscles, successively attacking the limbs and trunk, and ultimately spreading through the whole muscular system. When these conditions are observed, the proofs of death are conclusive, and it is unnecessary to wait for any sign of putrefaction. These changes are certainly the forerunners of putrefaction, as the process of putrefaction is itself the forerunner of the entire destruction of the body. It may safely be said that there has not been a single instance of resuscitation after rigidity had once commenced in a body. During the raging of epidemics, if additional evidence be required for early burial, it might be obtained by exposing a superficial muscle to the galvanic stimulus. If the fibres do not contract,

death is certain. If they do, this is no proof that the person can be restored to active life; but further time may be allowed before the body is committed to the grave. For a full discussion of rigor mortis, see a paper by Rossbach: Virchow's Arch., Bd. 51, 558.

Putrefaction. By putrefaction we are to understand those chemical changes which take place in dead animal matter, during which offensive gases are evolved. The ultimate effect of these changes is, after a longer or shorter period, to reduce the organic to the condition of inorganic compounds, consisting chiefly of water, ammonia, and carbonic acid. It is in the stage of transition that noxious effluvia are evolved from which the process derives its name. These consist of compounds of carbon, hydrogen, nitrogen, and sulphur.

This process does not begin to manifest itself in the dead body until after the cessation of rigor mortis, and generally about the third day. It is then observed, if the body has been exposed to the atmosphere in an apartment of mean temperature (60° F.), that the limbs and trunk become supple and pliant, and have a faint odor. The skin covering the abdomen becomes of a pale greenish color, which gradually deepens. A similar discoloration slowly makes its appearance on the chest, between the ribs, on the face, the neck, the legs, and, lastly, on the arms. The color appears to depend on the decomposition and infiltration of the animal fluids, espe

CHANGES IN THE VISCERA.

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cially of the blood, into the skin. In the neck and limbs it is observed to be more marked in the situation of the large venous trunks; and sometimes, indeed, the course of the superficial veins is accurately traced out by greenish-blue or dusky lines, which have been mistaken for marks of violence. Gaseous products are formed, not only in the hollow organs of the abdomen, but beneath the skin generally; so that on making an incision, the edges of the skin are rapidly forced apart or everted. The pressure of the confined gases accounts for the occasional escape of alimentary and fecal matter from the outlets-also for the escape of blood some days after death from recent wounds involving any of the large veins.

The gases generated in the cavities of the head and face by putrefaction appear to meet with the greatest resistance to their escape. The features become generally swollen or bloated, one or both eyes may be protruded, the eyelids swollen and dark-colored, the lips swollen and the tongue protruded between them, gaseous matter with fluid escaping in bubbles from the mouth and nostrils. As the skin of the face is generally livid, or even black, it is impossible, under these circumstances, to identify the body. In death from drowning, when the body is afterwards exposed to a warm atmosphere, the gases of putrefaction are so copiously produced that the head appears much larger than natural, and the skin of the trunk and limbs is distended with gas, giving to the whole of the discolored body a bloated appearance.

Changes in the Viscera.-During putrefaction various discolorations take place, first in the windpipe, then on the mucous surface of the stomach and bowels, often closely simulating the effects of disease or poison. The mucous membrane of the stomach may be found of various tints from a red brown, becoming of a brighter red by exposure to the air, to a deep livid purple or slate color, and sometimes black from decomposition of the blood. When the stomach is in contact with the spleen or liver, the lividity is often well marked and clearly defined through all the coats. The peritoneal or outer coat is of a greenish hue, and the course of the superficial vessels is marked by greenish-brown or black lines. These spontaneous changes, which are the result of putrefaction, may be easily mistaken for the effects of irritant poisons. There are no rules that will always enable a medical jurist to distinguish such cases. Much must depend on the process of putrefaction, and the period after death at which the body is examined: hence each case must be judged by the circumstances which attend it. We may presume that the redness has taken place during life, and is not a result of post-mortem changes: 1. When it is seen soon after death. 2. When it is met with in parts neither dependent nor in contact with other organs gorged with blood. 3. When it is accompanied by a considerable effusion of coagulated blood, mucus, or flakes of membrane, the result of ulceration, corrosion, or destruction of the coats of the viscera. When the body is not inspected until long after death, it is difficult to distinguish pseudo-morbid appearances from those depending on the action of irritant poison. In a really doubtful case, it is therefore better to withhold an opinion than to express one which must be purely conjectural.

Putrefaction takes place with variable rapidity. It commonly shows itself in this country about the second or third day in warm, and about the fifth or sixth day in cold weather. In some instances, however, the body has been found in an advanced state of putrefaction in the short period of sixteen hours after death, and in others the process has been greatly protracted. The time of its appearance is dependent on the duration of rigor mortis, and the condition of the body at the time of death.

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CHANGES IN THE VISCERA.

The changes caused by putrefaction in the dead body have in some cases been mistaken for those of gangrene in the living, and a person has in consequence been wrongly charged with manslaughter. Parts which are the seat of severe injury at the time of death undergo putrefaction more rapidly than those which have not been affected by the accident. When a body has undergone putrefaction generally, the effects of gangrene in a wound may be merged in the changes caused by this process, and great care should be taken in assigning these changes to one or the other condition. Gangrene implies the death of a part in the living body, and putrefactive changes take place in the dead part, as in the entire dead body. If changes resembling those of gangrene are found in a wounded limb while the rest of the body is not in a putrescent state, there may be some reason for the opinion that there was gangrene during life. In this case, however, due allowance should be made for the more rapid decomposition of wounded parts. The best evidence will be that which shows the actual condition of the injured part in the living body. If putrefaction is advanced, the opinion of a person who has not seen the deceased while living can be little more than a conjecture.

DEFINITION OF A POISON

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POISONING.

DEFINITION OF THE TERM

CHAPTER IV.

POISON.-MECHANICAL

IRRITANTS.-INFLUENCE OF HABIT, IDIOSYNCRASY, AND DISEASE.-CLASSIFICATION.-SPECIAL CHARACTERS OF CORROSIVE, IRRITANT, AND NEUROTIC POISONS.

Definition. A poison is commonly defined to be a substance which, when administered or taken in small quantity, is capable of acting deleteriously on the body: in proper language, this term is applied only to those substances which destroy life in small doses. This popular view of the nature of a poison is too restricted for the purposes of medical jurisprudence. It would obviously exclude numerous compounds, the poisonous properties of which cannot be disputed-as, for example, the salts of copper, tin, zinc, lead, and antimony; these, generally speaking, act as poisons only when administered in large doses. Some substances, such as nitre, have not been observed to have a noxious action except when taken in large quantity, while arsenic acts as a poison in a small dose; but in a medico-legal view, whether a man dies from the effects of an ounce of nitre, or two grains of arsenic, the responsibility of the person who criminally administers the substance is the same. Each may be regarded as a poison, differing from the other only in its degree of activity and in its mode of operation. The result is the same; death is caused by the substance taken, and the quantity required to destroy life, even if it could be always accurately determined, cannot enable us to distinguish a poisonous from a non-poisonous substance. If, then, a medical witness is asked "What is a poison ?" he must beware of adopting this popular view, or of confining the term "poison" to a substance which is capable of operating as such in one small dose.

In legal medicine, it is difficult to give such a definition of a poison as shall be entirely free from objection. Perhaps the most comprehensive which can be suggested is this: "A poison is a substance which, when absorbed into the blood, is [by a direct action-ED.] capable of seriously affecting health or destroying life." [The definition given by Dr. Alexander Winter Blyth in his work on Poisons is perhaps the best: "A substance of definite chemical composition, whether mineral or organic, may be called a poison, if it is capable of being taken into any living organism and causes, by its own inherent chemical nature, impairment of function."] There are various channels by which poisons may enter the blood. Some poisons are gases or vapors: these operate rapidly through the lungs; others are liquid or solid, and these may reach the blood either through the skin or through a wound, but more commonly through the lining membrane of the stomach or bowels, as when they are taken or administered in the ordinary manner. The latter chiefly give rise to medico-legal investigations. Some substances act as poisons by any one of these channels: thus arsenic is a poison whether it enters the blood through the lungs, the skin, or the stomach and bowels; but such poisons as those of the cobra, the viper, of rabies, and of glanders, appear to greatly affect the body only through a wound. When introduced into the stomach, some of these animal poisons have been found to be almost inert. In adopting the above defi

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