These anomalies, expansion of the tissue, and so-called softening of bone, on the one hand, and induration on the other, are, essentially, changes of its texture, and of its chemical composition: the latter involve as well the mineral constituents as the animal basement, and they must therefore be treated of amongst the diseases of texture.

6. Solutions Of Continuity, And The Process By Which They Are Repaired

The solutions of continuity in the osseous system, which result from injury, present many varieties. Bones may be laid bare by the removal of their periosteum, and of the soft parts covering them: they may be wounded by more or less sharp penetrating instruments; from whence ensue the various kinds of punctured, incised, and shot wounds, by which the bone is either partly or completely perforated, as well as the wounds inflicted in operations, as amputation, trephining, in the removal of portions of bones, etc. They may be broken, and, as is well known, the fracture may be transverse, oblique, or longitudinal; there may be but one fracture, or several, in the same bone: and sometimes a bone is shivered, or crushed, and the fracture which results is comminuted.

Incomplete fractures or fissures are, for the most part, met with in the skull; as when only one of the compact tables is fractured, or when the inner table is disunited, while the outer remains uninjured.

There is a remarkable form of incomplete fracture, in which a bone becomes bent. It occurs on flat bones, like the skull, as well as on long bones. It is produced sometimes by sudden and violent mechanical force, sometimes by more gentle means, which act through a longer period either uniformly or with intermissions. Its occurrence is favored by the softness of the bones, which in foetal life and in childhood exists naturally, but in subsequent periods of life is a morbid condition. These inflections of bone are chiefly observed in the skull of the new-born child as a consequence of the pressure which the head has undergone from the pelvis of the mother, or the forceps of the accoucheur: they may, however, be occasioned by accidental or intentional violence after birth; or they may take place in the bones of the limbs of persons who are affected with rickets or osteomalacia. They may be brought on by mechanical violence, or by excessive muscular contraction.

Any of these injuries may occur alone, or be combined in various ways with loss of substance: and further, they may be either simple, or complicated with considerable injury, bruising, and laceration of the soft parts, with shattering or splintering of the bone, with the presence of foreign bodies, with excessive degrees of inflammation of the soft parts, with gangrene, necrosis, etc.

In proceeding to the subject of the modes in which the most important injuries of bone are repaired, that by first intention, and that by way of suppuration, or second intention, I must refer, in order that the subject may be thoroughly understood, to what is said below on inflammation, suppuration, and necrosis of bone. The attention which has always been paid to the mode of union in cases of simple fracture has rendered that the foundation, as it were, upon which our ideas, as to the mode of repair in all other injuries of bone, have been based; and I, therefore, make it, both in its successful and unsuccessful issue, the subject of the following remarks.