AND DEVELOPMENT OF BONE. 197 



and canaliculi are still distinctly visible. In the former case we destroy 

 the organic tissue of the bone, retaining only the earthy matter, while 

 in the latter we have removed the earthy matter and preserved the 

 organic only. This obliteration of the lacunge and canaliculi, by the 

 action of heat, is a proof that the lacunae, with their canaliculi, are 

 lined with an organic membrane, in other words that an organized 

 tissue permeates the deepest portions of the bone. 



Thus the supply of blood to the bone is furnished by means of the 

 periosteal capillaries. The marrow of the bone possesses a circulation 

 independent of the periosteal vessels. "We notice in the diaphysis or 

 shaft, a foramen which gives passage to an artery, this artery, on reach, 

 ing the medullary canal, divides|into two branches, one to supply the 

 upper, aud the other the lower pr rtions of the medulla. The fora- 

 men or aperture is usually styled the nutritious foramen of the bone, 

 a misnomer, as you perceive, since the vessel to which it gives passage 

 is not destined to supply the bony tissue, but simply the contents of 

 the medullary canal. 



Let us now proceed to the special consideration of the periosteum ; 

 before doing so, however, it may be well to mention that, in reference 

 to the structure and purpose of this tissue, much difference of opinion 

 exists. Todd & Bowman, in their work on Physiological Anatomy, 

 a deservedly received text-book with the medical profession, say : 

 " Perhaps few questions have more divided the minds of physiologists 

 than that regarding the share taken by the periosteum in the growth 

 and regeneration of bone." Dr. Sbarpey was probably the first to 

 advance the opinion that (Carpenter's Principles of Human Physio- 

 logy, p. 279, 1853, xlmerican Edition,) " bone continues to increase in 

 diameter, by the formation of new layers upon its exterior, and that 

 these layers are formed, not, as usually stated) in a cartilaginous 

 matrix, but in the substance of a membrane that intervenes between 

 the proper periosteum and the surface of the bone, consisting of fibres 

 and granular cells." 



The following experiments fully establish this idea of Sharpey's, 

 they were conducted by Dr. Oilier during the year 1858, and may be 

 found recorded in the January number for 1859 of the Journal de 

 Physiologie, edited by Brown Sequard. 



The idea was generally entertained, previous to the observations of 

 Sharpey, that bone always originated in a cartilaginous matrix, and 

 that cartilage of necessity preceded the formation of bone. Now it 



