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Communication on Regeneration of Bone. 



By Sir William Macewen, F.K.S. 



(Received June 6, — Eead June 7, 1906.) 



The following experiments, illustrative of the part played by the various 

 structures in the regeneration of bone, were performed upon young animals 

 of two different varieties of the canine species, which were still in their 

 developmental period, two to four months. The specimens were secured from 

 6 to 12 weeks after the experiments had been performed, consequently the 

 animals would then be from three to six months old. 



A. — The periosteum removed from the entire circumference of the right 

 radius, the bone remaining in situ. 



B. — A circle of periosteum removed from the entire circumference of the 

 shaft of right radius and a silver ring placed upon the denuded bone. 



D and E. — Bone grafting from right radius. 



F and G. — Transplantation of bone en masse from right radius. 



J. — Preservation of periosteum. Bemoval of part of shaft of right radius. 

 Protection of divided ends of bone and medullary tissue by decalcified turkey 

 bone. 



K. — Preservation of periosteum and removal of underlying bone of right 

 radius to test the osseous reproductive capacity of this membrane. 



A. — The Periosteum Removed from the Entire Circumference of the Right 

 Radius, the Bone Remaining in situ. 



Dog A had the periosteum removed from the entire shaft of the right radius, 

 leaving only \ inch of periosteum on the diaphyseal side of the epiphyseal 

 lines. 



The operation was practically bloodless, aseptic healing ensued without 

 visible scar or adherent cicatrix. Along with this specimen there is the 

 corresponding left radius for comparison. 



Description of specimen as seen about 12 weeks afterwards : — 

 The shaft of the bone was found to be entirely covered with a layer of 

 newly formed connective tissue, closely investing the bone and adhering to it 

 much more firmly than periosteal tissue. It was found more difficult to detach 

 this fibrous layer from the bone than normal periosteum. The bone was 

 quite healthy and had acquired an abundant new blood supply. It had, 

 however, not increased circumferentially to the same extent as its fellow on 

 the left side. 



