tions to which the periosteum is subject. They may be ranged under three heads, viz. 1. Simple Inflammation; 2. Morbid Degeneration; 3. Transformation of this Tissue into a substance resembling bone.
1. Inflammation of the Periosteum, or Periostitis, as it is generally termed, is sometimes the result of external injury; sometimes it occurs as an idiopathic affection. From whatever cause it proceeds, inflammation of the periosteum is recognised by pain referred to the surface of the bone. When the bone which it covers is near the surface of the body, a distinct swelling, which is more or less circumscribed, may be felt. If we cut down upon and through this tumour, we find in some cases, that the periosteum is merely thickened, indurated, and separated from the bone, by the interposition of a gelatinous or sero-purulent matter. This may be called the acute variety of the disease. When it occurs in a chronic or indolent form, there is merely thickening, with increased density of the membrane, and little local uneasiness.
Chronic periostitis, which is termed Periostosis
