166 MEDICAL JURISPRUDENCE
4. Inhalation of Irrespirable Gases.—Inhalation of gases, such as carbon
dioxide, carbon monoxide, hydrogen sulphide, or smoke from a burning
house, will produce suffocation.
Mode of Death.—Usually death is due to asphyxia, but it may be due to
shock, when the heart stops by reflex action through the vagus nerves.
Fatal Period.—Death occurs on an average from four to five minutes
after complete withdrawal of air from the lungs, although cases have occur-
red in which death was almost instantaneous when the windpipe was block-
ed by a foreign body. Recovery may occur if treated within four minutes.
Post-mortem Appearances.-—These appearances are external and
External Appearances.—These may be due to the cause producing suffo-
cation, or to asphyxia.
Appearances due to the cause producing Suffocation.—In homicidal
smothering effected by the forcible application of the hand over the mouth
and nostrils, bruises and abrasions are often found on the lips and angles
of the mouth, and alongside the nostrils. The inner surface of the lips may
be found lacerated from pressure on the teeth. The nose may be flattened,
and its septum may be fractured from pressure of the hand, but these signs
are, in my experience, very rare. There may be bruises and abrasions on
the cheeks and malar regions, or on the lower jaw, if there has been a
struggle. Rarely, fracture or dislocation of cervical vertebrae may occur,
if the neck has been forcibly wrenched in an attempt at smothering with
the hand. No local signs of violence will be found, if a soft cloth or pillow
has been used to block the mouth and nostrils.
In compression of the chest, external signs of injury may not be pre-
sent, but the ribs are usually fractured on both sides. In homicidal com-
pression of the chest brought about by the hands or knees of a murderer
or by some other hard material, bruises and abrasions, symmetrical on both
sides, are usually found on the skin together with extravasation of blood in
the subcutaneous tissues. The ribs are also fractured symmetrically on both
sides, and the sternum is fractured, though rarely.
Appearances due to Asphyxia.—The face may be pale or suffused. The
eyes are open, the eyeballs are prominent, and the conjunctivae are con-
gested. The lips are livid, and the tongue is sometimes protruded. Bloody
froth comes out of the mouth and nostrils. The skin shows punctiform
ecchymoses with lividity of the limbs. Rupture of the tympanum may
occur from a violent effort at respiration.
Internal Appearances.—Mud or any other foreign matter may be found
in the mouth, throat, larynx or trachea, when suffocation has been caused
by the impaetion of a foreign substance in the air-passages. It may also be
found in the pharynx or oesophagus. The mucous membrane of the trachea
is usually bright red, covered with bloody froth and congested. The lungs
are congested and emphysematous. They may be lacerated or contused
even without anv fracture of the ribs, if death has been caused by pressure
on the chest, Punctiform subpleural ecchymoses (Tardieu's spots) are
usually present at the root, base, and lower margins of the lungs, and are
characteristic of death by suffocation, though they may be present in
asphyxial deaths from other causes. They are also found on the thymus,
pericardium, and along the roots of the coronary vessels. The lungs may
be found quite normal, if death has occurred rapidly. The right side of
the heart is often full of dark fluid blood, and the left empty. The .blood
does not readily coagulate; hence wounds caused after death may bleed.
The brain is generally congested, and so are the abdominal organs, espe-
cially the liver, spleen and Sidneys.