ondary projectiles, seems quite adequate.[18] Examination of any of
the skiagrams in which considerable comminution has taken place, shows
that the fragments are carried forward and perforate the tissues distal
to the fracture.

[Illustration: FIG. 49.--'Explosive' Wounds of Legs. Large irregular
entry (1 x 3/4 in.). First exit (2 in.) roughly circular. Second entry
wound, produced by bone fragments driven out of left leg, very large and
irregular (5 x 3-1/2 in.). The measurements were taken eight days after
infliction of the wounds. The right limb was amputated later for
secondary haemorrhage]

Fig. 49, although a poor delineation of the actual condition, shows well
the possible action of projected fragments, even after they have been
driven from the wound. In this case either a large or a ricochet bullet
entered on the outer aspect of the upper third of the left tibia; it
produced a severe comminuted fracture, the fragments from which,
together with the deformed bullet, then struck and perforated the upper
third of the right tibia. A large irregular entry wound 5 inches in
transverse diameter was produced in the second limb together with a
comminuted fracture of the bone. The right limb had eventually to be
amputated for secondary haemorrhage, but I am unacquainted with the later
history of the patient.

The mode of displacement of the lateral fragments when a wide shaft such
as that of the femur is struck, throws some light on that of the
displacement of soft tissues such as the component parts of a perforated
nerve or artery. The bullet, passing through, expends the chief part of
its energy in driving before it the fragments produced in its direct
course, while a minor part of the energy is expended on displacing the
lateral fragments, which are pushed to either side without becoming
separated from their periosteal attachment. The appearance, in fact,
somewhat suggests what might be expected were a small charge of dynamite
introduced into the centre of a small tunnel made across the shaft of
the bone. Examination of some of the skiagrams also illustrates another
point of interest, viz. that a certain degree of recoil on the part of
the bone results from the blow, since in many of them portions of the
mantle of the bullet and bone fragments are seen in that portion of the
track proximal to the fractured bone.

The importance of 'setting up' of the bullet is at once evident in
relation to the production of wounds