1'i.ATi: XXI. 



FIG. 60. Transverse section of the diaphysis of the femur in a human fa-fus, marer.-itrd with chromicacid. a. Con- 

 centric layer of connective tissue of periosteum, b. Bundles of connective tissue of the periosteum wliich run 

 longitudinally, cut across, c. Loose layer of internal periosteum, rieh in blood-vessels and young cells, which is in 

 course of transition into d, the trabecul3 of bone, as well as into its rich medullary tissue. The latter abounds in 

 blood-vessels aud cellular elements and occupies the space around and I .et ween the iraliwulte. The cells of the loose 

 tissue of internal periosteum must be regarded as analogous with the cells (ln>ne eormisrli-s) found in the bone tr*- 

 beculie, with those (osteoblasts) which lie i"m the bone trabecula;. and with those in the medullary tissue. In a 

 similar manner the intercellular substance of the loose internal i>.-iio steal layer (more or less distinct fibrous con- 

 nective tissue) are continuous with that of the boue trabecuht, aud of the spaces between them. p. 50. (Oc., 3; 

 Obj.,5. Tub.' half drawn out.) 



