196 CONNECTIVE TISSUE. 



arteries, veins, and capillaries is found, besides a certain 

 amount of medullary tissue, filling the space between the blood- 

 vessels and the walls of the canals. The medullary canals, 

 according to C. Langer, appear in the epiphyseal cartilage of 

 shaft-bones (femur) after the third month of embryonal life. These 

 canals are all in connection with the outer fibrous investment 

 of the cartilage i. e. the perichondrium, from which the blood- 

 vessels enter the canals. The vascular medullary spaces decrease 

 with the age of the individual, although a few such spaces have 

 been traced up to the thirtieth year of life (Bubnoff). They are 

 in intimate relation with both the progressive and regressive 

 development of cartilage. (See Fig. 74.) 



The cartilage corpuscles are never scattered uniformly 

 throughout the basis-substance, but always massed together, 

 and the amount of basis-substance between the different mem- 

 bers of a group of corpuscles is less than that which surrounds 

 the groups. The groups vary in their general form in different 

 portions even of the same cartilage. In epiphyseal cartilage of 

 young animals, the corpuscles are arranged in flat groups around 

 the articular surface ; they produce more or less globular or 

 elongated clusters in the middle portion, and on approaching the 

 diaphysis they are arranged in elongated rows. In a sagittal 

 (antero-posterior) section through such an epiphyseal cartilage, 

 the corpuscles appear oblong or spindle-shaped along the articu- 

 lar surface, which indicates that their broadest diameter runs 

 parallel with the outer surface. In the middle portion they are 

 more or less globular. Near the diaphysis they again become 

 discoid, appear flattened, oblong, or spindle-shaped if cut in 

 a sagittal direction, and circular in a direction vertical to the 

 shaft of the bone. 



With higher powers (300-500) of the microscope we recognize 

 that, especially in the middle portions of cartilaginous formations, 

 some corpuscles not infrequently lie very close to each other, so 

 as to mutually flatten their proximal surfaces. Between so- 

 called twin formations there is either a very narrow light rim or 

 a somewhat broader layer of basis- substance, and if an entire 

 group of corpuscles exhibit such twin formations (seen most dis- 

 tinctly in the cartilage of the trachea), the narrow frame between 

 the corpuscles in its regular arrangement presents a very pretty 

 appearance. These double formations have been considered, for 

 the last twenty years or more, proofs of the division of cartilage 

 cells. This is a very mistaken idea, for it is impossible to under- 



