BONE. C xi 



communicating by canaliculi, remain in the partially ossified cells. When this 

 hard tissue is decalcified by an acid, the original cells and cartilaginous matrix 

 become apparent. 



Fig. LTL, A. 



Fig. LYL, B. 



Fig. LVL A AND B REPRESENT TWO TRANSVERSE SECTIONS OP GROWING BoNE, AS IN 

 FlQ. LIIL, BUT MUCH MORE MAGNIFIED (ABOUT 120 DIAMETERS). 



They show the lateral coalescence of the primary bony areolae and the thickening of the 

 sides of the enlarged cavities by new osseous deposit. The section A is made almost imme- 

 diately below the surface of ossification ; B, is somewhat lower, and shows the cavities still 

 more enlarged and their sides more thickened than in A. The new osseous lining is 

 transparent, and appears light in the figures ; the dark ground within the areolse is owing 

 to opaque debris, which collected there in grinding the sections. It must be further 

 noticed that the letter A within the larger figure, marks a place where a bony partition 

 had been accidentally broken away, for the large space was naturally divided into 

 two. 



As ossification advances towards the ends of the bone, the portion as yet 

 cartilaginous continues to grow at the same time, and increases in every 

 dimension. The part already osseous increases also in circumference ; the 

 medullary canal, of which for some time there is no appearance, begins to 

 be excavated in the interior by absorption, and the sides of the shaft acquire 



, 



