W& ON THE COMPOSmCW, STRUCTURE 



an important bearing upon resections and rhinoplastic operations. It 

 suffices, however, for our purpose to allude merely to this subject. 



The periosteum, therefore, by virtue of its deep layer is most con- 

 elusively shown by these experiments to generate bone,, and it is by 

 Tirtue of this property that bone normally increases in diameter ; its. 

 increase in length being provided for by means to which we shall 

 presently refer. 



Paul Broea speaking of these experiments says, " Oilier, with great 

 ingenuity, has revived a subject, in regard to vphich it v?as thought 

 that nothing remained to be discovered, and it has yielded a rich 

 harvest of entirely neve facts ;; the discoveries which he has made with 

 reference to the functions of the periosteum, may be numbered 

 among the most important of ou.r age. The idea of transplanting 

 portions of this membrane, of burying them in the midst of the- 

 fleshy tissites, of grafting them in positions distant from the skeleton,, 

 ©f transferring them evea from one animal to another, — this idea is. 

 peculiarly his own, and, thanks to him, we now know that the perios- 

 teum does not require, for the production of bone, to be in contact 

 with osseous tissue. This membraiae carries with it wherever it may 

 fee placed among living tissaes its special osteoplastic power, its- 

 inherent property. The fact had long been suspected, yet not posi- 

 tively known^ and to Oilier belongs the merit of having demonstrated 

 the truth in a manner both rigorous and striking." 



We conclude that the periosteum is composed of two essentially 

 distinct portions having wholly different properties — that the external 

 or fibrous layer is the medium of connection between the tendons of 

 muscles and the bony levers to which these muscles give motion, and 

 moreover, serves as a basis of support for the capillary bloodvessels. 

 which go to the nutrition of the bony tissue ; that immediately be- 

 neath this fibrous envelope there exists a cellular layer having osteo- 

 genetic or bone producing power ; that this layer may be transplanted 

 to a distance from its original site, and while among the living tissues 

 of the animal is capable of producing perfect bony tissue, that is. 

 possessed of Haversian canals, lacvmse and their accompanying cana- 

 liculi ; and that it is by virtue of this layer that bone increases in diam-.- 

 eter. It is also manifest that a continuation of this periosteum is ta 

 be met with in the densest structure of bone lining these canals, 

 lacunse and canaliculi j for, as heretofore remarked, if we submit a 

 thin section of bone to the prolonged action of heat, all trace of the; 



