become shorter, until the patient is hardly ever free from pain.  Localised tenderness can almost always be elicited by percussion, or by compressing the bone between the fingers and thumb.  The pain induced by the traction of muscles attached to the bone, or by the weight of the body, may interfere with the function of the limb, and in the lower extremity cause a limp in walking.  The limb may be disabled from involvement of the adjacent joint, in which there may be an intermittent hydrops which comes and goes coincidently with exacerbations of pain; or the abscess may perforate the joint and set up an acute arthritis.

The diagnosis of Brodie’s abscess from other affections met with at the ends of long bones, and particularly from tuberculosis, syphilis, and new growths, is made by a consideration of the previous history, especially with reference to an antecedent attack of osteomyelitis.  When the adjacent joint is implicated, the surgeon may be misled by the patient referring all the symptoms to the joint.

The X-ray picture is usually diagnostic chiefly because all the lesions which are liable to be confused with Brodie’s abscess—­gumma, tubercle, myeloma, chondroma, and sarcoma—­give a well-marked central clear area; the sclerosis around Brodie’s abscess gives a dense shadow in which the central clear area is either not seen at all or only faintly (Fig. 121).

Treatment.—­If an abscess is suspected, there should be no hesitation in exploring the interior of the bone.  It is exposed by a suitable incision; the periosteum is reflected and the bone is opened up by a trephine or chisel, and the presence of an abscess may be at once indicated by the escape of pus.  If, owing to the small size of the abscess or the density of the bone surrounding it, the pus is not reached by this procedure, the bone should be drilled in different directions.

[Illustration:  FIG. 121.—­Radiogram of Brodie’s Abscess in Lower End of Tibia.]

#Other Forms of Acute Osteomyelitis.#—­Among the less severe forms of osteomyelitis resulting from the action of attenuated organisms are the serous variety, in which an effusion of serous fluid forms under the periosteum; and growth fever, in which the child complains of vague evanescent pains (growing pains), and of feeling tired and disinclined to play; there may be some rise of temperature in the evening.

Infection with the staphylococcus albus, the streptococcus, or the pneumococcus also causes a mild form of osteomyelitis which may go on to suppuration.