STRUCTURAL GUANOES DUE TO DAMAGE. 



323 



comparatively undifferentiated condition. No granulations are, 

 therefore, produced, but the cells are simply stimulated to a forma- 

 tive activity that is abnormal to the part. This is the group of 

 chronic inflammations, of which three or four examples will be 

 cited. 



Chronic periosteal inflammation may be induced by a number of 

 damaging causes of slight intensity, but repeated application. The 

 response which the cells of the periosteum make to this irritation 

 is a revival of their formative activity and the production of bone, 

 which forms an " epiphyte," or other osseous excrescence, apparently 

 springing from the surface of the older bone. Similar new-forma- 

 tions of bone may take their origin from the endosteum, forming 



Fro. 286. 



Cirrhosis of the liver; chronic interstitial hepatitis. (Kaufmann.) a, lobules of the liver; 

 b, increased interstitial fibrous tissue, the result of the inflammatory process ; c, collec- 

 tion of nuclei in the fibrous tissue, showing that the process is still in progress ; d, thick- 

 ened capsule of the liver. 



layers that encroach upon the lumina of the Haversian canals or 

 the medullary cavity of the bone. These deposits are more diffuse 

 than those springing from the external surface of the bone, probably 

 because they arise as the result of a more widespread irritation, such 

 as the presence of some noxious substance in the circulation, and not 

 from a localized point of irritation. 



Another example of this group is presented by cirrhosis of the liver, 



