f vein or portion of fat-bearing fascia.

_Injuries of nerves resulting from_ #gun-shot wounds# include: (1) those
in which the nerve is directly damaged by the bullet, and (2) those in
which the nerve-trunk is involved secondarily either by scar tissue in
its vicinity or by callus following fracture of an adjacent bone. The
primary injuries include contusion, partial or complete division, and
perforation of the nerve-trunk. One of the most constant symptoms is the
early occurrence of severe neuralgic pain, and this is usually
associated with marked hyperaesthesia.

#Regeneration.#--_Process of Repair when the Ends are in Contact._--_If
the wound is aseptic_, and the ends of the divided nerve are sutured or
remain in contact, they become united, and the conducting paths are
re-established by a regeneration of nerve fibres. There is a difference
of opinion as to the method of regeneration. The Wallerian doctrine is
that the axis cylinders in the central end grow downwards, and enter the
nerve sheaths of the distal portion, and continue growing until they
reach the peripheral terminations in muscle and skin, and in course of
time acquire a myelin sheath; the cells of the neurolemma multiply and
form long chains in both ends of the nerve, and are believed to provide
for the nourishment and support of the actively lengthening axis
cylinders. Another view is that the formation of new axis cylinders is
not confined to the central end, but that it goes on also in the
peripheral segment, in which, however, the new axis cylinders do not
attain maturity until continuity with the central end has been
re-established.

_If the wound becomes infected_ and suppuration occurs, the young nerve
fibres are destroyed and efficient regeneration is prevented; the
formation of scar tissue also may constitute a permanent obstacle to new
nerve fibres bridging the gap.

_When the ends are not in contact_, reunion of the divided nerve fibres
does not take place whether the wound is infected or not. At the
proximal end there forms a bulbous swelling, which becomes adherent to
the scar tissue. It consists of branching axis cylinders running in all
directions, these having failed to reach the distal end because of the
extent of the gap. The peripheral end is completely degenerated, and is
represented by a fibrous cord, the cut end of which is often slightly
swollen or bulbous, and is also incorporated with the scar tissue of
the wound.

#Clini