i 



INFLAMMATION. 369 



the former osseous basis-substance now divides into a number 

 of flat, fusiform, nucleated bodies. As a matter of course, it is 

 the reticular bioplasson within the basis- substance, and not the 

 basis-substance itself, furnishing the material for these elements, 

 which are not really newly formed bodies, but only made visible 

 and re-arranged in new groupings. 



The final result of the melting or dissolution of the basis-sub- 

 stance is the appearance of medullary spaces. They may arise 

 from bone-corpuscles and their surrounding basis-substance, in- 

 dependently of the vascular canals in the middle of the bone-tis- 

 sue. This fact was known previously by Rokitansky. Medullary 

 spaces may also have their origin in the borders of vascular 

 canals, and the nearer the wound of the bone, the larger and 

 the more irregularly excavated are the medullary spaces come 

 from the vascular canals. They are always packed with globular 

 or spindle-shaped corpuscles, while in their centers blood-vessels, 

 containing blood-corpuscles, are found. 



Running from the widened vascular canals, now transformed 

 into medullary spaces, are channels filled with medullary corpus- 

 cles, which penetrate the interstices between the systems of 

 lamellae. The spaces which arise in the vicinity of the bone-cor- 

 puscles unite with those of the widened vascular canals and 

 interstices ; and in intense inflammation, up to the eighth day, 

 the formerly compact bone is transformed into a cancellous 

 structure i. e., only narrow trabeculae of unchanged bone are 

 left, between which are large spaces containing medullary cor- 

 puscles. In still more intense inflammation, especially that pro- 

 duced by boring into the compact bone with a pointed hot iron, 

 the bone-tissue in the district of inflammation around the wound 

 is to a great extent transformed into medullary tissue, holding 

 newly formed blood-vessels, and in this tissue, only very small, 

 irregular islands of the former compact bone are found. Obvi- 

 ously, the juvenile condition of the bone is reestablished by this 

 process, even in its coarser anatomical relations. (See Fig. 156.) 



The elements which have newly appeared bear a close resem- 

 blance, so far as their shapes are concerned, to those present in 

 normal vascular canals, between the wall of the blood-vessel and 

 the wall of bone. They are nothing more than medullary ele- 

 ments in the stage of indifference eventually osteoblasts. 



In slight degrees of inflammation, the medullarj^ elements, up 

 to the eighth day, may, at the surface of the inflamed bone, again 

 be transformed into the so-called " osteoid " tissue by infiltration 

 24 



