ic "leg of mutton" shape. In both diseases there is a
tendency to pathological fracture. It is difficult also in the absence
of skiagrams to differentiate the condition from syphilitic and from
tuberculous disease. If the diagnosis is not established after
examination with the X-rays, an exploratory incision should be made; if
dead bone is found, it is removed.

In typhoid fever the bone marrow is liable to be invaded by _the typhoid
bacillus_, which may set up osteomyelitis soon after its lodgment, or it
may lie latent for a considerable period before doing so. The lesions
may be single or multiple, they involve the marrow or the periosteum or
both, and they may or may not be attended with suppuration. They are
most commonly met with in the tibia and in the ribs at the
costo-chondral junctions.

The bone lesions usually occur during the seventh or eighth week of the
fever, but have been known to occur much later. The chief complaint is
of vague pains, at first referred to several bones, later becoming
localised in one; they are aggravated by movement, or by handling the
bone, and are worst at night. There is redness and oedema of the
overlying soft parts, and swelling with vague fluctuation, and on
incision there escapes a yellow creamy pus, or a brown syrupy fluid
containing the typhoid bacillus in pure culture. Necrosis is
exceptional.

When the abscess develops slowly, the condition resembles tuberculous
disease, from which it may be diagnosed by the history of typhoid fever,
and by obtaining a positive Widal reaction.

The prognosis is favourable, but recovery is apt to be slow, and relapse
is not uncommon.

It is usually sufficient to incise the periosteum, but when the disease
occurs in a rib it may be necessary to resect a portion of bone.

#Pyogenic Osteomyelitis due to Spread of Infection from the Soft
Parts.#--There still remain those forms of osteomyelitis which result
from infection through a wound involving the bone--for example, compound
fractures, gun-shot injuries, osteotomies, amputations, resections, or
operations for un-united fracture. In all of these the marrow is exposed
to infection by such organisms as are present in the wound. A similar
form of osteomyelitis may occur apart from a wound--for example,
infection may spread to the jaws from lesions of the mouth; to the
skull, from lesions of the scalp or of the cranial bones
themselves--such as a syphilitic gumma or a sarcoma which has fung