238 



Sir W. Macewen. 



[June 6, 



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. 



Dog B had a circle of periosteum, comprising the whole circumference of 

 the right radius and measuring |- inch in breadth, raised from about the middle 

 of the shaft. A flattened silver ring was made to encircle the denuded bone 

 at this part. 



The operation was bloodless, the wound healed aseptically without visible 

 scar and without adherent cicatrix. The bones of the left limb are preserved 

 for comparison. 



Description of specimen as seen 12 weeks after : — 



The right radius was covered — at the part that had been denuded of the 

 periosteum — with a newly formed connective tissue which was more firmly 

 attached to the bone than that of the normal periosteum on the shaft above 

 and below this part. After denuding the bone from this newly formed 

 connective tissue and from the periosteal covering, there was no trace of the 

 silver ring to be seen. The shaft of the bone was smooth all over and if the 

 wire still existed it must have become enveloped in the bone. There was, 

 however, a thickening of the shaft at one part and it was considered probable 

 that the silver ring lay underneath. The bone was scraped through in a 

 vertical direction and after penetrating the bone for about £ inch, the silver 

 ring was exposed, completely buried in firm osseous tissue. Three other 

 apertures were scraped through at different parts of the circumference of the 

 shaft so as to expose the silver ring at each. The thickness of the new bone 

 covering the wire in front was fully | inch and it was a little less behind. 

 Thus, the silver ring placed upon the bone denuded of periosteum had in 

 three months become completely enveloped in newly formed bone, §■ inch in 

 thickness. 



The shaft operated on is smaller in circumference than its fellow in left 

 limb, the diminution in bulk being most apparent at the part which was 

 denuded of periosteum — but the new bone at this part is denser than that on 

 the other parts of the shaft which were not operated on. 



D and E. — Bone Grafting. 



Two dogs, named D and E, of different species, had the periosteum entirely 

 removed from the right radius, after which a circle of bone including the 

 whole circumference of the shaft was removed from each. These circles of 

 bone being kept apart were each divided into small fragments, and those 

 removed from animal D were placed in the gap left in the radius of E, 

 while those from animal E were placed in the gap left in the radius of D. 



