Posted in Science & Nature


In 1907, a physician called Duncan MacDougall tried to scientifically prove the existence of the human soul. He weighed patients dying from tuberculosis at the time of death and studied the change in body mass. After observing the death of six patients, he noted that the body mass lightens at the time of death, which he attributed to the soul leaving the dead body. He published the official average mass of the soul as 21 grams.

Unfortunately, this experiment was complete nonsense. MacDougall failed to use the scientific method. The tiny sample size of six patients, the broad range of weight loss (21 was an arbitrary number he chose and was not even the proper mean mass) and the lack of control in the study environment are some of the major flaws of the experiment procedure. In fact, it is more likely the change in body mass was due to the many changes that occur post-mortem. For example, the lungs recoil and breathe out air, moisture escapes the body and as the sphincters relax, excrements are expelled.

Many people still believe the urban myth that the soul has an objective weight of 21 grams (possibly augmented by the movie 21 grams). Another interesting fact is that MacDougall also experimented on dogs (except instead of using dying dogs, he killed them himself). He found that dogs lose no weight when dying and thus claimed that dogs have no soul.



Posted in Psychology & Medicine


When a person dies, they leave a body. How does the body change after death? There are four main post-mortem events: algor mortis, livor mortis, rigor mortis and putrefaction. Forensic pathologists use these phenomena and an autopsy to determine the time of death, hearing out the final words of the deceased.

With death, all physiological functions cease. Therefore, the body produces no more heat and begins to cool (algor mortis), evident when touching the corpse. The rectal temperature is measured for an accurate reading. 
As blood is no longer flowing, red blood cells sink due to gravity. They sink to capillaries in the lowest point of the body, causing a purple-red rash on the skin of the area. This is known as livor mortis, or lividity. It appears first about 1~2 hours after death, and worsens with time. On the other hand, the other areas of skin become pale due to the lack of blood.
2~3 hours post-mortem, one can observe the jaw stiffening. This is called rigor mortis. It is caused as ATP is needed for muscle relaxation, and ATP production stops with death. This leads to the muscle becoming rigid, fixating on the position at the time of death. About 6~7 hours later, rigor mortis spreads to the entire body and completely fixes the body 10~12 hours later. After about 72 hours, rigor mortis dissipates and the corpse is limp again.

Putrefaction is the process of microbes decomposing the body – more commonly called rotting. After death, cells die from the lack of energy and are broken down by enzymes. As the immune system also ceases function, microbes easily infiltrate the body and begin converting organic material into inorganic material.
Microbes release gases as it digests the corpse, which collects and causes bloating. The main gases are carbon dioxide, methane and hydrogen sulphide, producing the rotting smell, attracting insects to the corpse.
The key insects studied by pathologists are arthropods and flies. They can estimate the time of death from observing what species are present on the body, and at what stage of the life cycle they are at. For example, 0.5~1 hour post-mortem, flies arrive and lay eggs, which hatch into maggots at 10~24 hours, which becomes cocoons after 8~12 days, which hatch into adult flies at 12~14 days post-mortem.

There is no dignity in death. The rich, the powerful, the kind, the happy – everyone rots away by nature after they die.