Molecular Death refers to the death of cells.

Signs of death are those that indicate that the organism has ceased to live. Cessation of the necessary functions may give rise to apparent death, but without other indications it cannot be diagnosed with certainty.

The necessary signs are:

Algor Mortis

Algor Mortis, a fall of the temperature to that of the surrounding atmosphere. Following tetanus it may, however, be preceded by a distinct rise, continuing for some hours.

Livores Mortis

Livores Mortis, or post-mortem lividity, are the discolored areas that appear in the dependent portions of the body as a result of the dilatation of the blood-vessels. It is often of great importance to distinguish this condition from the discoloration following a blow. In the first the color will disappear on pressure, but in a bruise it will remain, as the blood is not within the vessels.

Rigor Mortis

Rigor Mortis, or post-mortem rigidity, is a stiffness due to the coagulation of the albumin of the muscles with the formation of myosin. It is first seen in the muscles of the neck and jaws, then extends downward, involving the entire body.

It generally comes on within four to twelve hours, but may appear immediately or be delayed for twenty-four hours. At the end of twenty-four to forty-eight hours it usually passes off.

If death has occurred suddenly and the individual is in good health, it appears much more quickly than when death has taken place slowly.

Decomposition is the infallible sign. Its appearance depends upon the surrounding temperature, taking place more quickly in hot weather. It is first noticed as a greenish discoloration of the abdominal wall, and is due to the sulphuretted hydrogen from the intestines acting upon the iron contained within the hemoglobin.

The tissues soften and there is more or less odor, due to the formation of various gases.

Loss of elasticity, relaxation of the sphincter muscles and loss of transparency of the cornea, and dilatation of the pupils complete the list.

Apparent death may occur in hysteria, catalepsy, submersion, cholera, exposure to cold, and action of electricity. It is detected by the absence of the signs of true death. The tissues will appear reddish if a light is held behind them, blood will flow from a wound, moisture will collect on a mirror held in front of the face, and the muscles will react to electricity.