Different constricting agents may make quite similar marks. Marks may be made on the neck within a limited time after death, similar to those made during life. Tidy’s experiments led him to fix this limit at three hours for ecchymoses and six hours for non-ecchymosed marks. Taylor,[791] however, doubts if such marks could be made one hour after death. He says that the period cannot be stated positively, and probably varies according to the rapidity with which the body cools.
It is, however, unlikely in such post-mortem attempts at deception that the other conditions usual in strangulation would be found—such as lividity and swelling of face; prominence and congestion of eyes; protrusion of tongue; rupture of surface air-vesicles and apoplexies in the lung; congestion of larynx and trachea, etc.
No conclusion can be drawn from the presence or absence of any single appearance.
A cord may be found near a body or even around its neck; there may even be a mark around the neck. These may be attempts at deception.
Marks much like those of violence may be made by tight collars and handkerchiefs remaining until the body is cold.
Cases are reported of bodies having been first strangled and then burnt or hung to cover the crime; and of partial suffocation by gags, followed by or coincident with strangulation (see Cases 18, 20, 24).
In apoplectics with short and full neck we may find at the borders of the folds of skin in the neck one or more depressions, red or livid, that bear some resemblance to the marks of a ligature; but on section there are no ecchymoses.
Froth, tinged with blood, in the air-passages is considered by Tardieu[792] one of the most constant signs of strangulation.
The marks of topical medical applications, as plasters, sinapisms, etc., must not be confounded with marks of violence.
In strangulation by ligature the marks are usually horizontal; in hanging, oblique. In hanging too they are usually dry and parchmenty. Ecchymoses are more marked in strangulation.