397 



The R6le of the Various Elements in the Development and 



Regeneration of Bone. 

 By Sir William Macewen, F.B.S. 



(Received and Read January 24, 1907.) 



(Abstract.) 



The present inquiry has been undertaken with the view of obtaining 

 data, chiefly by direct experiment, as to the rdle which the various elements 

 play in the development and reproduction of bone. This communication 

 deals with a part of the subject, under two heads : — A, the potentiality of 

 the periosteum as a factor in the production of bone, and B, the regeneration 

 •of bone from proliferation of osseous tissue. The following is a brief ri&wrnA 

 -of the paper : — 



A. Potentiality of Periosteum as a Factor in Reproduction of Bone. 



(1) To test this, a complete cylinder, constituting a portion of the shaft of 

 a long bone, was removed while the periosteum was preserved intact. This 

 showed, ten weeks afterwards, an osseous defect, constituting a gap in the 

 continuity of the shaft. 



(2) Periosteum free from osseous plaques was removed and transplanted. 

 This was not followed by reproduction of bone, but by absorption of the 

 periosteum. 



(3) Duhamel's silver ring experiments are discussed and the correctness of 

 the deductions drawn therefrom are questioned. 



In order to test whether the bone cells or the periosteum produces the 

 bone which covers the silver rings, three experiments, each differing from the 

 other, were performed, in which silver rings were placed on bone deprived of 

 its periosteum, with the result that in each case the rings became covered 

 with bone. 



B. The Regeneration of Bone, from Proliferation of Osseous Tissue. 



The periosteum is shown to be a limiting membrane controlling the 

 osteoblasts, as illustrated in fractures, when the periosteum is intact and 

 when it is torn. The production of callus is not inherently greater in the 

 lower animals than in man — the amount of callus in both depends on the 

 limitation of the periosteum and the amount of movement. (4) Direct 

 ■experiment, showing that a long bone deprived of its periosteum continues 

 to grow, (5) so also do the flat bones of the skull. (6) Bone may be made 

 vol. lxxix. — B. 2 G 



