STIirCTl'KES ENGAGED IN THESE I'KOt'ESSES. 1 ."> 



duced by the contiguity of the new formation. Carrying out, 

 therefore, the principles at present regarded as regulating the 

 reciprocal functions of textures and vessels, the subjacent textures 

 disappear in consequence of a disturbance of their own forces, 

 consequent upon the appearance of new forces residing in the 

 cellular layer. The disturbance arid gradual annihilation of the 

 natural forces residing in the subjacent textures, is indicated by 

 the gradual disappearance of these. That new forces, not former- 

 ly existing in the part, are developed, appears from the formation 

 of the cells of the cellular layer. As these appear in rapid suc- 

 cession, and disappear as rapidly, the subjacent textures also dis- 

 appear, either by previous solution and subsequent absorption by 

 the properties and powers of the former ; or under the peculiar 

 circumstances of inflammatory action by the more vigorous 

 growth of the former, monopolizing the resources of the part, the 

 latter dissolving and disappearing by the usual channels of the 

 returning circulation, more rapidly, but according to ordinary 

 laws. 



From this view of the process, it appears that so far from con- 

 sisting in a diminution of the formative powers of the part, such 

 a progressive ulceration is actually an increase of it. The ap- 

 parent diminution, is a consequence of the extremely limited 

 duration of existence of the cells of the absorbent layer, which 

 die as rapidly as they are formed, disappearing after dissolution, 

 partly as a discharge from the surface, but principally through the 

 natural channels by which the debris of parts, which have al- 

 ready performed their allotted functions, are taken up into the 

 organism. 



When a portion of dead or dying bone is about to be separated 

 from the living, the process which occurs is essentially the same 

 as that which has now been described. The haversian canals 

 which immediately bound the dead or dying bone, are enlarged 

 cotemporaneously with the filling of their cavities with a cellular 

 growth. As this proceeds, contiguous canals are thrown into one 

 another. At last, the dead or dvincr bone is connected to the 



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living by the cellular mass alone. It is now loose, and has be- 

 came so in consequence of the cellular layer which surrounds it 

 presenting a free surface and throwing off pus. 



