XIV INTRODUCTION.
that the irritation of disease, however excited in it, is so commonly followed by the action of forming osscous substance among the surrounding soft parts, some of these being more prone to this action than others; hence, the ossifications ensuing in the yarious structures adjacent to diseased, or injured, bones. Here, more- over, it may be well to regard in one vicw the whole series of ossifications and osseous productions arising either as distinct diseases, or as the consequence of disease in their neighbourhood. Morbid ossifications and osseous productions may be arranged under the following heads :—
I. Unorganized masses of calcarcous salts, found in various tumors, especially in the fibrous tumors of the uterus, also constituting the apparent ossifica- tions in the eoats of arteries.
2. Ossifications of original tissues, as of fibrous mem- brane, tendon, muscle, &c. These are, probably, but the ossifications of one tissue, the cellular, a component of all these structures.
Fibrous membranes are remarkably prone to ossifi- eation; one example of which, among many, is the long-enduring ulcer upon the leg, followed by ossification of the periosteum bencath the uleer and around it, accompanicd by ossification of the inter- osscous ligament between the tibia and fibula, often converting it into a thick plate of bone. The character of its organization is not the sole cause of the tendency of fibrous membrane to ossify. Its vital properties, and its locality in connexion with �
