It presents a combination of properties that makes it singularly difficult to conceal permanently.

It is bulky and of an awkward shape, it is heavy, it is completely incombustible, it is chemically unstable, and its decomposition yields great volumes of highly odorous gases, and it nevertheless contains identifiable structures of the highest degree of permanence.

It is extremely difficult to preserve unchanged, and it is still more difficult completely to destroy.

The essential permanence of the human body is well shown in the classical case of Eugene Aram; but a still more striking instance is that of Seqenen-Ra the Third, one of the last kings of the seventeenth Egyptian dynasty.

Here, after a lapse of some four thousand years, it has been possible to determine, not only the cause of death and the manner of its occurrence, but the way in which the king fell, the nature of the weapon with which the fatal wound was inflicted, and even the position of the assailant.