224 



CONNECTIVE TISSUE. 



the juvenile skeleton, this structure composes the epiphyseal 

 ends and the central portions of the shaft-bones, and the central 

 portions of flat and short bones. (See Fig. 86.) 



Cancellous bone-tissue of the embryo is invariably striated 

 and non-lamellated. In the fully developed skeleton it exhibits 

 usually indistinct lamellae. The spaces between the trabeculee 

 of cancellous bone are in youth filled with a richly vascular- 

 ized medullary tissue, the "red medulla" of Virchow; while with 



FIG. 86. TIBIA OF A NEWLY BORN PUP. LONGITUDINAL SECTION. 

 CHROMIC ACID SPECIMEN. [PUBLISHED IN 1873.] 



T, trabeculae of bone-tissue containing bone corpuscles; M, medullary spaces filled 

 with medullary tissue, holding blood-vessels in the most central portions. Magnified 200 

 diameters. 



advancing age the spaces exhibit fat- tissue, Virchow's " yellow 

 medulla." 



In very old persons there is an increasing deficiency of both 

 the cancellous and compact bone-tissues j the bone corpuscles are 

 also very small and few in number, as many of them have been 

 transformed into basis-substance. 



The relation between the cancellous and the compact structure 

 differs in different bones. As a rule, the short bones are largely 



