474 



LECTURE XIX. 



that the fibrous tissue becomes condensed (sclerotic), 

 though only partially so, the condensation beginning at 

 the bone and proceeding outwards in certain directions ; 

 in this way there arise, at first resting like columns upon 

 the bone, hardish cones * which are united by transverse 

 bands, parallel to the surface of the bone, and thus con- 



FiG. 132. 



stitute this network. If now acetic acid be applied to 

 these parts, we see at once that the whole fibrous mass 

 which fills the alveoli, contains the most wonderful con- 

 nective-tissue-corpuscles, which are so arranged, that 

 next to the trabeculae all around they lie in concentric 

 rows, whilst in the most internal parts of the marrow 

 they constitute stellate corpuscles which anastomose with 

 one another, as you have already seen on many occasions. 

 But that in some parts the trabeculae have already 

 become true bone, one may very beautifully convince 



Fig. 132. A portion of Fig. 131, more highly magnified, o, o. The osteoid tra- 

 beculae ; m, m, m the primary medullary spaces with spindle-shaped and reticulating 

 cells. 300 diameters. 



* These are the little columns mentioned in p. 110 as being perpendicular to the 

 long axis of the bone, and as intervening between the Haversian system Transl. 



