32 OF THE PERIOSTEUM. 



thickness of each lamellae, and which Deutsch, supposed to be 

 extremely minute tubes. Some of these dots or lines, see Fig. 

 5, appear to transverse more than one lamella, though the 

 majority, as Miescher describes them, are very short, and 

 appear like the separations between the granules of the carti- 

 lage of the bones, from which the calcerous portions had been 

 removed.* The result of the observations of Miescher, is : 

 1st. That the spongy structure of bones, is nothing but an 

 amplification of the canaliculi, as is shown by Gerdy. 

 2d. That the medullary canal, as shown by its formation 

 and name, is provided for the purpose of union or anastomosis, 

 between these enlarged canaliculi, and, 



3d. That therefore, the canaliculi, girdled with concentric 

 lamellae and containing a medulla, composed of a great body 

 of vessels, is the primary element or form of the osseous tissue, 

 which is subsequently more fully developed. 

 Scarpa is therefore correct in saying that the solid parts of 

 bone, are formed of the cellular structure in a more compacted 

 state. The reticulated tissue, which forms a sort of link 

 between the cellular substance and the medullary cavity, and 

 the osseous filaments which project every where from the 

 parieties of the cavity into the medulla, are the remains of the 

 walls of the cells, the integrity of which is impaired in conse- 

 quence of the enlargement of the orifices by which they com- 

 municate together. 



Of the Periosteum. 



Bones are invested with a firm membrane .denominated 

 periosteum, which is of a fibrous texture, and in some places 

 may be separated into different lamina. The external surface 

 of periosteum is connected with the contiguous parts by cel- 

 lular membrane ; the internal surface is connected with the 

 bone by a great number of fibres and blood-vessels. The 

 orifices of these vessels become apparent, when the periosteum 

 is separated from bones in the living subject. 



* Subsequent microscopical observations, as will be shown further on, have 

 confirmed this supposition of Deutsch. p. 



