386 GENERAL ANATOMY. 



In both cases, moreover, the end of the bone ultimately un- 

 dergoes other changes. In general, it becomes greatly di- 

 minished in volume and weight. The canal, which is at first 

 filled by the spongy rarefaction of the compact substance, is 

 re-established, but is closed at the extremity by a bony pro- 

 duction placed over it like a lid. 



609. Deep necrosis* of the long bones presents at the 

 same time interesting phenomena of separation and osseous 

 production. 



When the medullary membrane of a long bone is destroyed 

 in a living animal, by introducing into its canal a foreign body 

 which tears or cauterizes it, the whole limb to which the bone 

 belongs swells, becomes painful, and has its temparature in- 

 creased. At a later period abscesses form, which open and 

 remain fistulous. There is seen, or felt through the openings, 

 a moveable bone in the midst of the pus, and contained in 

 another bone which is hollow. The internal bone, which be- 

 comes in time more and more loose, sometimes gets engaged 

 by one of its extremities in one of the apertures of the external 

 bone, and is even at length expelled. It is then seen to have 

 the length of the diaphysis of the original bone, and a variable 

 thickness, but which sometimes entirely equals that of the 

 original bone. The new bone, however, being freed of the 

 foreign body, and being connected from the commencement 

 with the extremities of the old bone, which are now become 

 its own extremities, gradually contracts within itself. The 

 suppuration diminishes, and at length entirely ceases, when 

 the walls, which have approached each other to such a degree 

 as to touch, are agglutinated together, and at length become 

 entirely confounded. 



* Chopart and Robert. De JVecrosi Ossium Theses Jlnatomico-Chir. 

 Parisiis, 1766. Troja. De Novorum Ossium, &c. Paris, 1775. Blumen- 

 bach, in Richter, Chir. Biblioth. B. VI. David. Observ. sur une Maladie 

 Connue sous le nom de necrose. Koeler. Experimenta circa regenerationem 

 ossium. Getting. 1786. J. P. Weidmann. De Necrosi Ossium. Franc, ad 

 Mcen. 1793, fol. Russel. Practical Essay on a Certain Disease of the 

 Bones called Necrosis. Edinb, 1794. A. H. Macdonald, de Necroiti ac 

 calk. Edinb. 1799. Macartney, in Crowther's Pract. Obs. on the Diseases 

 of the Joints. Lond. 1808. Charmeil, DC la Regeneration des Os. Metz. 1821. 



