jg2 PROFESSOR SYME ON THE POWER OF THE PERIOSTEUM 



condition ; and where it covered the posterior surface of the tibia, though quite 

 detached from the old bone, had not suffered any farther change. 



There is here, then, an instance of a bone dying suddenly in consequence of 

 acute inflammation, without any thickening having previously formed in its neigh- 

 bourhood, and nevertheless succeeded by the production of a new osseous shell, 

 which evidently could not proceed from the old bone, and no less evidently depend- 

 ed upon an ossific process resident in the periostemn. 



As Nature is not capricious or variable in her proceedings, I regard this case 

 as sufficient of itself, without any farther evidence, to establish the ossific power 

 of the periosteum. But, with the view of making the matter still more clear, I 

 performed the following experiments. I exposed the radius of a dog, and removed 

 an inch and thi'ee-quarters of it together with the periosteum. At the same 

 time I exposed the radius of the other leg, and removed a corresponding portion 

 without the periosteum, which was carefully detached from it and left quite en- 

 tire, except where slit open in front. Six weeks afterwards the dog was killed, 

 and the bones examined. In the one from which a portion had been taken to- 

 gether with the periosteum, the extremities were found extended towards each 

 other in a conical form, with a great deficiency of bone between them, and in its 

 place merely a small band of tough Ugamentous texture. In the other, where the 

 periosteum had been allowed to remain, there was a compact mass of bone not 

 only occupying the space left by the portion removed, but rather exceeding it 

 (see Fig. II.). This experiment was repeated, and aflbrded the same results. 



I next exposed the radius of another dog, and separated the periosteum from 

 the bone as in the former experiment ; but then, instead of cutting out the denu- 

 ded bone, inserted a thin plate of metal between it and the periosteum. The 

 edges of the membrane, as weU as those of the skin, were sewed together, and the 

 wound healed kindly. At the end of six weeks I dissected the limb, and found 

 a deposition of osseous substance in the periosteum, forming a bony plate exterior 

 to the metal, and not connected with the old bone except by the membrane. 



I lastly exposed the radius of a dog, and cut away the periosteum to the 

 same extent that it had been merely detached in the experiment just mentioned, 

 and surrounded the denuded bone with a piece of metal. At the end of six 

 weeks, I found a thick tough capsule formed, enclosing the metallic plate, but 

 having no osseous substance in it. 



The evidence which has now been adduced seems to me sufficient for putting 

 beyond all question the power of the periosteum to form new bone, independently 

 of any assistance from the old one. I submit it, with deference, to the Societ}'', in 

 the hope, that those members who have directed their attention to the subject, 

 will give it their dispassionate consideration, and either admit the opinion which 

 it supports, or shew the fallacy by which it has misled. 



