How would death by cyanide feel?

How a person really dies

Bang - the victim grabs his heart and drops dead. A crime cliché - but wrong. What really happens when you die? What biological and chemical changes are taking place?

Humans are not dead from one second to the next. Dying is a slow process, the manifestations and “side effects” of which begin before the cardiovascular system has finally failed. Researchers have known since the 18th century, when people who drowned could be successfully resuscitated for the first time, that cardiac arrest does not necessarily mean the end of life.

In particular, the discovery of electricity helped the doctors of the time to get the hearts of the supposedly dead back on their feet. Today we know that up to 50 hours after the cardiac arrest, individual muscle groups can still be excited electrically, i.e. can be animated to move by the influence of electricity. It is only up to 100 hours after a person dies that all the cells in his body have died - so-called biological death has occurred.

With the introduction of transplant medicine in the middle of the last century, however, the need arose for a definite definition of death. This is where brain death offered itself: If the overall function of the brain is irrevocably extinguished, machines can keep the affected person's body functional for almost any length of time. But the condition is irreversible, a return to life as we know it is no longer possible.

The Transplantation Act therefore defines brain death as a prerequisite for the removal of organs. Several criteria must be met to diagnose brain death. These include the loss of consciousness, the absence of reactions of the brainstem to various stimuli and a cessation of spontaneous breathing. These findings, which can be checked without the help of a machine, must be confirmed by a new examination after a certain period of time (12 to 72 hours).

Since waiting for this time is impractical when an organ is to be removed, the missing brain function can also be proven by measurement - for example via an electroencephalogram (EEG), which must show zero activity of the brain waves for 30 minutes. The lack of blood supply to the brain is also a sure sign of death, which can be detected by nuclear medicine (scintigraphy) or via ultrasound (sonography). These examinations must be carried out by doctors who are not involved in the organ removal.

Death spots and rigor mortis

The coroner seldom faces the problem of having to prove someone's death. Because he is called when the police or another doctor has already established that a person has died under unexplained circumstances. The decisive factor here is that an unnatural death was diagnosed (for example at the post-mortem examination).

Such a finding automatically leads to the involvement of the investigating authorities, which then call in the forensic doctor. The death of a person is only considered natural if there is a clear cause for which a third party bears no responsibility. Old age, for example, is not a natural cause of death - a person always dies from a specific organ failure. Choking on vomit after previous alcohol or drug poisoning must not be diagnosed as natural death.

Whatever the exact reason for calling in the authorities, the coroner is now on the scene. Forensics has already locked it so that no clues can get lost. The location of the corpse has already been documented. Was she clothed? Was she under a blanket? Temperature and humidity are just as important for further assessment as their course over the previous lying time of the dead (which a call to the meteorologist and the landlord - who knows the heating bills - can clarify).

The first examination of the corpse now assesses death spots and rigor mortis. When the heart stops pumping blood through veins and arteries, something called hypostasis occurs. Due to the influence of gravity, the blood and all other body fluids sink to the bottom.

This process can begin even before final death when blood pressure drops sharply. The result is the so-called churchyard roses, light reddish discoloration of the skin, which can be observed above all behind the ears and on the cheek parts below the head. The name actually goes back to the cemetery (which used to be in the churchyard).

After cardiac death, the blood sink rate accelerates. It collects in the fine blood vessels of the skin, always on the underside of the corpse. The dead spots are initially still small and light red in color. Gradually they combine to form larger areas. If individual veins can no longer absorb the blood, smaller bleeding, roughly the size of a grain of rice, occurs under the surface of the skin, which is called vibex (plural: vibices).

Death while cleaning the aquarium?

At first the blood still contains oxygen, hence the reddish color. But this is used up relatively quickly. The dead spots then take on a blue-violet color. However, there are exceptions: If the corpse is in a cold environment, oxygen can penetrate the skin and stop the change in color.

The death spots also remain bright red if the victim is poisoned with carbon monoxide. The odorless gas that can escape from defective ovens, for example, is preferentially absorbed by the red blood cells, so that people suffocate even though there is actually still enough breathable oxygen in the air.

If there is no source of carbon monoxide in the area and the area is not particularly cold, there could be poisoning with hydrocyanic acid compounds (cyanides) or sodium fluoroacetate. The toxicity of hydrogen cyanide should be known to crime readers - only the cliché of the bitter almond smell doesn't fit, because most people cannot even perceive the alleged bitter almond smell.

The colorless, odorless and easily water-soluble sodium fluoroacetate, on the other hand, is still an insider tip among crime writers, as it is only found in plant species in the southern hemisphere (where it is also partially approved as a pesticide) and at the same time highly toxic. The poisoning can already occur through skin contact or inhalation. The lethal dose in humans is 5 to 10 milligrams per kilogram of body weight. Treatment is next to impossible, death occurs within a few hours. Incidentally, fish are largely insensitive to sodium fluoracetate. An aquarium lover could well perish cleaning the fish tank while his scaled pets swim lively.

If the dead spots are neither blue-violet nor light red, poisoning is also the cause. Sodium chlorate as well as nitrates and nitrites (salts of nitric acid or nitrous acid) give the stains a brownish color. Sodium chlorate used to be found in pesticides, but is no longer permitted there. If you ever come across a stewardess as a murderess or suspect in a crime thriller, she could have obtained sodium chlorate from the oxygen generators that supply the passengers' breathing masks with air in an emergency.

Finally, a green coloration of the dead spots indicates poisoning with hydrogen sulfide. The typical smell of rotten eggs prevents the victim from coming into contact with it unnoticed. However, hydrogen sulfide also numbs the olfactory nerves, so that you no longer notice an increase in its concentration in dangerous areas. It also collects near the ground because it is heavier than air.

The corpse was moved!

Dead spots form wherever there is no pressure on the skin. Therefore, the places where the corpse rests on the floor are mostly left out of them and easily recognizable by the coroner. So the doctor will lift or turn the body. Are the dead spots in the right places? Butterfly-shaped recesses over the shoulder blades, on the buttocks and on the calves are typical when the corpse is lying on its back. Clothing, especially tight-fitting clothes, can also prevent stains from forming in an area. If you lie on your stomach or on your side, the situation is reversed accordingly.

It may be a strange sight, but there is a good reason why the coroner appears to be massaging the corpse's skin in the next step. The dead spots can be pushed away to a greater or lesser extent, depending on the length of time you lie down. About five and a half to six hours after death, the stains can still be removed by applying more or less pressure with the thumb. Over time, more and more pressure is needed. Up to 17 hours after death you need very strong pressure with a tool to achieve at least a partial displacement. If the cell deterioration continues, however, the blood then escapes from the vessels into the tissue and can then no longer be pushed away.

Whether and when the corpse was moved after the time of death can also be judged on the basis of the death spots. As long as the cell decay has not progressed very far, the dead spots are re-formed in the right place if you turn the body or even just change the contact surfaces. This is completely the case until about six hours after death. For another six hours or so, the spots shift partially, after which they stay in place.

A corpse lying on its back with death spots on its stomach but not at all on its back was probably moved at least twelve hours after the crime. If there are no other traces of the crime (blood, etc.) where the corpse was found, but if the dead spots are exactly where they belong, the murderer must hurry and have the dead body moved to another location no more than six hours after the crime .

If death occurred in a full bathtub, the waterline can often be recognized by the death spots.

The evaluation becomes more complicated when the victim bleeds to death internally or externally due to numerous injuries. Then there may not be enough blood left for the dead spots. If the right ventricle fails, the blood builds up in the body veins, with the result that the spots can also appear on the front of the neck and face, despite the fact that the patient is lying on his back.

Dead spots can also be found inside the body. This can be important in the case of death by hanging: In this case, they should be detected during the autopsy on the parts of the intestine lying below.

When the eye stays open

It is one of the moving scenes in a crime thriller when the inspector tries to close the girl's eyes but is no longer able to do so. This is due to the rigor mortis occurring. When a person dies, all of his muscles initially relax. However, the muscle cells try to maintain their life cycle. This succeeds for a maximum of three to four hours, during which the limbs of the deceased are still easily mobile. After that, however, the two protein groups, actins and myosins, which normally slide into one another like the two sides of a zipper during muscle contraction, fuse together in such a way that the muscle is no longer able to move. This usually happens first with the muscles of the lower jaw and neck, followed by the upper limbs, trunk and finally the lower limbs (Nysten rule).

It is difficult to objectively examine rigor mortis: the examining doctor tries to move as many different joints as possible and assesses the amount of force he needs to do so. After a certain time, about eight hours, rigor mortis is fully developed. Then the joint breaks rather than moving. Before that, however, not only does the effort required vary depending on how long the corpse lies, but also another phenomenon: the re-entry of rigor mortis.

If rigor mortis is not yet complete, the coroner can usually still break the restricted mobility of a joint. It then becomes easy to move again, as not all of the muscles' fibers are affected by the rigidity. Now it takes a certain amount of time, which also depends on the length of time the corpse has been lying, until the joint is completely stiff again. This effect occurs no more than six to eight hours after death.

The fused proteins dissolve completely into their components over time. That is the moment when the investigator can finally close the lids of the murdered girl, because now the rigor mortis also dissolves again. How much time elapses until then, however, depends extremely on the ambient temperatures. While the solution begins after about 2.5 days at room temperature and should be complete after three days, the rigidity can last for weeks in winter conditions. This happens for the same reason that they keep perishable food in the refrigerator: cold prevents decomposition processes.

Apparent life after death, cold as a corpse, dry skin, putrefaction and putrefaction, wax corpses and mummies

Apparent life after death

Anyone who had to dissect a frog or fish in biology class is familiar with the phenomenon: if you apply electricity to a nerve cell, sudden muscle reactions can occur. These are not the animal's signs of life. However, they show that the underlying cells are still fulfilling their function. If you know how long after death this will be the case, you can infer the time of death.

This set of instruments is also available to forensic doctors. The spectrum ranges from methods that you can use directly at the place where the corpse was found (and which are usually quite crude) to laboratory techniques.

The physician can still cause the Zsako muscle phenomenon 90 to 150 minutes after death: If he hits the biceps muscle of the upper arm forcefully with a hard object, it will contract and the forearm will move as a result. You may be familiar with the test from your medical examination, in which a small wooden hammer is tapped on the lower part of the thigh just above the knee: if the reflex works, the lower leg twitches forward. The trick also works with other muscles of the skeletal muscles, such as on the back of the hand.

If the person has been dead for more than 2.5 hours but less than four to five hours, the muscles no longer contract, but one or more bulges (technical term: idiomuscular bulge) are formed, which are clearly visible under the skin or at least palpable. The more time passes, the weaker the reaction, but the longer it lasts, in the final phase even for up to a day.

As we recall from the frog experiment, reactions can not only be induced mechanically, but also electrically. For this purpose, forensic doctors have portable stimulation devices at their disposal, which emit defined current impulses. If you insert an electrode in the eyelid, for example, the entire half of the face (around 3.5 hours after death), the upper half of the face (4.5 hours), both eyelids, part of the upper eyelid or the eye muscles react, depending on the length of time the corpse has been lying there immediately at the injection site (up to 13.5 hours after the time of death).

The facial muscles are similarly electrically stimulated - after two to six hours you will only be able to induce a twitch in the immediate vicinity of the electrodes. The uncertainty with this method is great, however, it is about half of the lying time determined from the test. If the electrical impulses set the upper half of the face in motion, it can only be said with certainty that the person must be dead between two and seven hours (4.5 hours being the most likely value).

Finally, forensic doctors can also trigger reactions chemically - in this case on the muscles of the iris that open and close the pupil. To do this, the dead person is injected with a drug such as adrenaline, atropine or acetylcholine under the conjunctiva. A few minutes later, the effects will occur - or not, depending on the length of time that has passed since death. For example, adrenaline should react 14 to 46 hours after death, and atropine only 3 to 10 hours post mortem (after death).

Cold as a corpse

The idea that corpses feel cold is correct. On the one hand, this is due to the expectation that people have when touching bare skin - one usually feels the body temperature of the skin at a little below 37 degrees. Therefore, it does not need to cool down too much to create an unpleasant impression.

In fact, after death, body temperature falls relatively slowly, at around 0.5 to 1.5 degrees per hour. In the anus, measured around eight centimeters inside the sphincter (this is where the temperature comes closest to the core temperature inside), the temperature initially remains constant for two to three hours while the skin slowly cools down. The speed of cooling afterwards depends heavily on the environmental conditions.It then basically obeys an exponential equation, but the corresponding coefficients are very different from case to case.

If the ambient temperature is below 10 degrees, the cooling rate doubles or triples compared to a temperature of 21 degrees. People with greater body mass cool down up to a third more slowly than lean people. A hunched-up posture delays the release of heat to the environment, as does clothing or a duvet. However, if the clothing is damp, the corpse cools down faster. The same is the case when the wind removes the moist air or the dead person is even in the water. In practice, it must also be taken into account that when the corpse was found, the surroundings may have been changed: Did the police put up spotlights? Did someone open the windows or turn on the heating?

In practice today, the time spent lying in the corpse is determined primarily with software that tries to take all of these factors into account. Nomograms, which the forensic doctor reads according to a certain algorithm and then converted with correction factors, are an older method of determination. If all environmental conditions are known at any point in time, the determination of the time of death via the core body temperature is considered to be the most accurate method.

Even so, the careful coroner tries to use all other methods to increase security. If the person is dead for a maximum of one day, the exact time of death can usually be narrowed down to one or two hours using all options (but not more precisely).

Dry skin

The dead also suffer from dry skin - even if “suffering” is the wrong word. This is simply due to the fact that with the heartbeat, all mechanisms that keep the skin and mucous membranes moist are also terminated. Eyelids or tongue stop moving. The moisture on the surface of the skin evaporates and the sweat glands no longer produce any replenishment.

Just one to two hours after death, the conjunctiva of the eyes dries (if they are not closed) and changes color from yellow-brownish to (later) blackish. If the eyes are closed, the cornea will only become cloudy after 24 hours. This is followed by the lips and other mucous membranes, after which the skin on the fingertips turns reddish-brown.

The drying up usually begins at the points furthest from the trunk. Damaged parts of the skin dry faster than undamaged areas because the existing moisture can evaporate better here.

Putrefaction and putrefaction

Now comes the moment when the boastful, fluffy young investigator in crime novels likes to be put in their place. The fact that the dead are no longer alive is no longer a question that a doctor would need to answer: the answer is already given by your own nose. At the latest at the sight of the corpse, which was already rotting in the air after a week, the investigator's assistant had an attack of acute nausea, after which he appeared again very modestly.

As uncomfortable as the sight of a rotting body may be, rot is also a good sign. If the deceased should have died of an infectious disease, there is no longer any danger from him. The regime has now taken over all the bacteria and fungi that are optimally adapted to the dead organism. Pathogens, on the other hand, are phenomena of life; that their host dies is actually not in their biological interest.

The fact that putrefaction occurs at all is because the cells are no longer supplied with oxygen. You change your program and supply yourself with energy - the tissues dissolve (autolysis), protective mechanisms that prevent this in the living body now fail. For some of the bacteria that always live on the skin and mucous membranes, this improves the living conditions and displaces all the competitors who cannot benefit from them. The lack of oxygen means that mainly anaerobic processes (which do not need oxygen) take place. That is precisely the definition of putrefaction versus putrefaction, which we will discuss in a moment.

Nice to look at, the detective assistant has already felt that firsthand, a rotting corpse is not. Initially, the skin turns greenish (one to two days post mortem). This is because bacteria break down the red hemoglobin in the blood into sulfur compounds that look green. “Varicose veins” show up all over the body - more precisely, the veins under the skin are now very clearly visible (three to five days of lying time).

The gases that the microorganisms produce (mainly carbon dioxide, ammonia and hydrogen sulfide) inflate the inside of the body; first the lips, then the stomach, breasts and limbs enlarge enormously (eight to twelve days after death). The gas pressure inside presses liquid out of the body orifices, which at first glance could be mistaken for blood, but which actually contains the decomposition products of the tissues. Pregnant women can give birth to a coffin: the fetus is forced out of the abdomen by the putrefactive gases. Gas bubbles form between the layers of the skin. When these burst, the skin tears open. Hair and nails peel off,

How quickly the putrefaction runs off again depends heavily on the environmental conditions. The times given above apply to storage of the corpse in the air at 20 degrees Celsius. On average, Casper's rule applies: one week in the air corresponds to two weeks of lying in water or eight weeks in the ground.

At some point, however, there will always come a time when putrefaction turns into putrefaction. If oxygen also reaches deeper areas due to the increasing self-dissolution and damage to the corpse, the anaerobic processes are replaced by aerobic ones and other microorganisms take over. The tissue now disintegrates less moist, more dry and fibrous. The smell changes: the putrid aroma of hydrogen sulfide disappears. Actually, a rotting corpse shouldn't smell at all, because the main products of putrefaction, water, carbon dioxide, urea and phosphate, have little or no odor of their own. In practice, however, you will hardly find a corpse that does not also (to a lesser extent) go through putrefaction processes. In intermediate stages, pungent-smelling ammonia compounds can also be produced.

The coroner will gladly consult an entomologist on a corpse in this condition. Based on the known development cycles of many species of flies and beetles, conclusions can also be drawn about the time of death. The more different stages of development of different types the expert finds, the more precise statements he can provide. If species 1 becomes a larva about three days after egg-laying, but the larvae are on average a few days old, the corpse must have been in this place for a certain period of time.

Wax corpses and mummies

In a very dry environment, instead of rotting, the corpse may be mummified - not to be confused with the artificial mummification known from ancient Egypt. Mummies can always arise naturally if the microorganisms responsible for the putrefaction lack one of the bases necessary for reproduction - such as moisture, but also warmth (ice mummy). If the corpse is embedded in substances that are toxic to the bacteria (bitumen, possibly also concrete), putrefaction cannot occur and a poisonous mummy is created.

Wax corpses can form, especially in cool, damp surroundings. This is actually a problem in some cemeteries with impermeable loam or clay soils, because the buried dead show no signs of external decomposition even after 50 years, when the grave sites usually deteriorate. How do you treat such a corpse with respect?

The coroner knows that the term fatty wax corpse is actually inappropriate, because the bodies actually contain hardly any fats and no wax at all. Rather, in the absence of air, fatty acids, their salts and glycerine are produced from the subcutaneous fatty tissue. These form an impermeable protective layer that prevents or at least slows down rot and putrefaction in the body. The consistency of this protective layer is waxy, hence the term.

It is rather rare, but not impossible, for the dead body to stop its putrefaction itself. This happens, for example, if a long-term chemotherapy took place or the person was treated with high-dose antibiotics. However, the effects of these drugs are always limited to a few days. They make it more difficult to determine the time of death insofar as the forensic doctor may not have the doctor's report on hand.

The text is the first chapter of the book Schöner Dieben - Kleine Mordkunde for crime fans, which exposes the most common mistakes in crime novels and thrillers. It describes how the coroner identifies the dead and goes into more detail about the specifics of the different types of death. Currently available as an eBook for 99 cents (DRM-free, so suitable for use on all eReaders).

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