180 



BOXE AND BONE MARBOW 



within the shaft of the bone, the epiphysial cartilages continue to 

 grow. Finally, however, ossification begins in the epiphysis, and, 



FIG. 168. TRAN SECTION OF A RIB OF AN INFANT. 

 Developing bone. Hematein and eosin. Photo, x 67. 



proceeding in the same manner as in the shaft, results in the for- 

 mation of primary spongy bone, some of which is absorbed and 



