cur in callus, or at the seat
of old fractures, but the evidence so far is inconclusive as to the
causative relationship of the injury to the new-growth. They are
treated on the same lines as tumours occurring independently of
fracture.

#Badly United Fracture--Mal-Union.#--Union with marked displacement of
the fragments is most common in fractures that have not been properly
treated--as, for example, those occurring in sailors at sea; and in
cases in which the comminution was so great that accurate apposition
was rendered impossible. It may also result from imperfect reduction,
or because the apparatus employed permitted of secondary displacement.
Restlessness on the part of the patient from intractability, delirium
tremens, or mania, is the cause of mal-union in some cases; sometimes
it has resulted because the patient was expected to die from some
other lesion and the fracture was left untreated.

Whether or not any attempt should be made to improve matters depends
largely on the degree of deformity and the amount of interference with
function.

When interference is called for, if the callus is not yet firmly
consolidated, it may be possible, under an anaesthetic, to bend the
bone into position or to re-break it, either with the hands or by
means of a strong mechanical contrivance known as an osteoclast. In
the majority of cases, however, an open operation yields results which
are more certain and satisfactory. When the deformity is comparatively
slight, the bone is divided with an osteotome and straightened; when
there is marked bending or angling, a wedge is taken from the
convexity, as in the operation for bow-leg. To maintain the fragments
in apposition it may be necessary to employ pegs, plates, bone-grafts,
or other mechanical means. Splints and extension are then applied, and
the condition is treated on the same lines as a compound fracture.

[Illustration: FIG. 5.--Multiple Fractures of both Bones of Forearm
showing mal-union.]

#Delayed Union.#--At the time when union should be firm and solid, it
may be found that the fragments are only united by a soft
cartilaginous callus, which for a prolonged period may undergo no
further change, so that the limb remains incapable of bearing weight
or otherwise performing its functions. The normal period required for
union may be extended from various causes. The most important of these
is general debility, but the presence of rickets or tuberculosis, or
an interc