468 



LECTURE XVIII. 



FIG. 130. 



analyze the substance deposited, no trace of any plastic 

 exudation is found ; the swollen spot appears on the 

 contrary organized in its whole thickness from without 

 inwards, and this most distinctly close to the bone, 

 whilst towards the surface of the periosteum the struc- 

 tural relations can be less readily unravelled. This 

 swelling may under certain circumstance increases to a 



very considerable extent. In 

 periostitis we do not unfre- 

 quently see, you know, regu- 

 lar nodes formed, and one 

 need only recall the more 

 physiological history of callus 

 after fracture. In either of 

 these cases we seek in vain 

 for an exudation. If the 

 thickened layers are traced in 

 the direction of that part of 

 the periosteum which still re- 

 mains unthickened, we can 

 very distinctly see what Du- 



hamel long ago exhibited in a very beautiful manner, 

 but is forgotten over and over again, namely, that the 

 layers which constitute the thickening are ultimately all 

 of them continued into the layers of the periosteum. 

 As little as the periosteum is unorganized, so little are 

 the thickened layers without organization. Microscopi- 

 cal examination shows at the surface of the bone a 

 slightly striated basis-substance, and in it, numerous, 



Fig. 130. Vertical section through the periosteum and periosteal surface of a 

 parietal bone from a child. A. The proliferating layer of the periosteum with 

 anastomosing networks of cells and division of nuclei. B. Formation of the 

 osteoid layer by means of the sclerosis* of the intercellular substance. 300 

 diameters. 



* Sclerosis signifies thickening with condensation. From a MS. Note by the 

 Author. 



