The X-ray appearances of the bones affected are of a striking character; apart from the outgrowths of bone or “tumours” there is evident a widespread alteration in the internal architecture of the bones, which suggests analogies with other disturbances of ossification such as achondroplasia and osteomyelitis fibrosa.  The condition is one that runs in families, sometimes through several generations; we have more than once seen a father and son together in the hospital waiting-room.

As regards treatment, there is no indication for surgical interference except when one or other tumour is a source of disability as by pressing upon a nerve-trunk or by locking a joint, in which case it is easily removed by chiselling through its neck.

[Illustration:  FIG. 141.—­Multiple Cartilaginous Exostoses in a man aet. 27, the same as in Fig. 140.]

Diffuse Osteoma, Leontiasis Ossea.—­This rare affection was described by Virchow, and named leontiasis ossea because of the disfigurement to which it gives rise.  It usually commences in adolescence as a diffuse overgrowth first of one and then of both maxillae; these bones are enlarged in all directions and project on the face, and the nasal fossae and the maxillary and frontal sinuses become filled up with bone, which encroaches also on the orbital cavities.  In addition to the hideous deformity, the patient suffers from blocking of the nose, loss of smell, and protrusion of the eyes, sometimes followed by loss of sight.  The condition is liable to spread to the zygomatic and frontal bones, the vault of the skull, and to the mandible.  The base of the skull is not affected.  The disease is of slow progress and may become arrested; life may be prolonged for many years, or may be terminated by brain complications or by intercurrent affections.  In certain cases it is possible to remove some of the more disfiguring of the bony masses.

A less aggressive form, confined to the maxilla on one side, is sometimes met with, and, in a case of this variety under our own observation, the disfigurement, which was the only subject of complaint, was removed, after reflecting the soft parts, by paring away the excess of bone; this is easily done as the bone is spongy, and at an early stage, imperfectly calcified.

A remarkable form of unilateral hypertrophy and diffuse osteoma of the skull, following the distribution of the fifth nerve, has seen described by Jonathan Hutchinson and Alexis Thomson.

#Chondroma.#—­Cartilaginous tumours, apart from those giving rise to multiple exostoses, grow from the long bones and from the scapula, ilium, ribs, or jaws.  They usually project from the surface of the bone, and may attain an enormous size; sometimes they grow in the interior of a bone, the so-called enchondroma.