BONE. 



bone lacunae, but also between these and all the cavities which 

 carry nourishing material in the bone. This whole canal sys- 

 tem can be demonstrated by filling it with colored materials 

 (Figs. 43 and 44). The part of the ground substance imme- 

 diately surrounding the lacunae is more resistant toward re- 

 agents than elsewhere. By the action of concentrated acids, a 

 preparation showing merely the canal system can be obtained, 

 for the whole intercellular substance, with the exception of a 



FIG. 44. 



From a section through the bone of a roebuck. The bone cavities are seen from the 



side. X 8oO. 



very thin layer lining the cavities, is dissolved. If a section is 

 cut so that the lacunae can be looked into from above, small 

 openings can be seen which represent the mouths of the small 

 canals or processes (Fig. 43). 



In these lacunae lie the bone cells. These are membra neless 

 cells, each of which fills the whole cavity. Their form corre- 

 sponds with the cavities in which they are situated. In prepa- 



