GERDY ON THE INTIMATE STRUCTURE OF BONE. 



vascular orifices which touch each other at their circumference 

 like the rings round the orifices of a tin colander.* 

 The canaliculated tissue, is developed in all the bones of 

 the body, but is least evident in the flat. It is an assemblage 



of small canals traversed by 

 vessels, and has heretofore 

 been described as a part of 

 the cellular or spongy. In 

 the long bones it is found on 

 the inner surface of the com- 

 pact tissue, and separated 

 from the reticulated tissue of 

 the medullary canal, by a 

 parchment-like lamin, pierced 

 with holes for the passage of 

 anastomosing vessels. These 

 canaliculi form elongated cavi- 

 ties, which are slightly tor- 

 tuous, nearly parallel with 

 one another, not exactly 

 rounded, and have their pa- 

 rietes pierced with holes to 

 admit of anastomosis be- 

 tween the vessels which line 

 them ; they run in the long 

 bones in the direction of their 

 length, and in the thick bones, 

 from one articular surface to 

 the other. They arise in part 6 



Fig. 2.f 



* This we shall find is the opinion of the microscopists in regard to the struc- 

 ture of all compact bony layers. 



f Fig. 2. Vertical section of the inferior third of the tibia. 1. 1. Compact 

 tissue of the body of the bone, becoming gradually thinner towards the inferior 

 extremity. 2. 2. Reticulated tissue in the lower part of the medullary cavity 

 occupying the axis of the cylinder of bone. 3. 3. Canaliculated tissue, the vas- 

 cular canals of which deiach themselves successively from the compact walls of 

 the bone, and run nearly parallel with each other towards the extremity of the 

 bone. 4. 4. Cellular tissue of the epiphysis, composed of interrupted canaliculi, 

 and of tubular cells, which terminate nearly perpendicularly upon the articular 

 surface. 6. 6. The articular or sub-cartilaginous compact tissue, extremely thin. 



