488 EXOSTOSIS. 



actions of the extensor tendons implanted within it ; to 

 which cause we must also attribute the pain that is some- 

 times observed in these cases. 



CHAPTER XVIl. 



DISEASES OF THE BONES. 

 CARIES. 



Bones are subject to chronic inflammation, which termi- 

 nates, as in soft structures, in resolution, suppuration, or in 

 mortification. The living powers of parts being generally- 

 proportioned to their vascularity, bones, as having less blood 

 than other structures, are weaker, and their diseased actions 

 are slower : consequently they do not readily inflame, but, 

 having so done, the process frequently produces death of 

 them. Thus bone will die : it is however necessary to 

 observe that the restorative powers here, as in other in- 

 stances, are more active than in man. 



Exfoliation. — When death has taken place in a bone, the 

 process of its removal is called exfoliation, and such process 

 is conducted by the absorbents. This is effected partly by 

 the suppurative and partly by the ulcerative actions ; or by 

 sloughing, though in a very slow mode, which removes so 

 much of the hving as forms the union with the dead ; by 

 which means the decayed portion, losing its attachment, 

 comes away. In caries, therefore, it must be our endea- 

 vour to assist this exfoliation. Sometimes, from an actual 

 want of power to accomplish this, the caries spreads ; in 

 which case we must rouse the living bone into greater 

 action by liberal diet, and a free allowance of ale or stout, 

 or even spirits ; while chloride of zinc, from its disinfecting 

 power, is freely injected, to destroy the fcetor that accom- 

 panies the sloughing of bone. 



EXOSTOSIS. 



Bones being organized like the soft parts of the body, we 

 might therefore suppose that they were also susceptible 

 of disease ; the most prominent instance of which is exostosis 

 or bony tumour. This is the consequence of a morbid 



