RESORPTION WITHOUT OSTEOCLASTS (OSTEOLYSIS) 539 



were more numerous, and in their immediate vicinitv the organic 

 matrix appeared less dense. 



Chicks which received vitamin D also showed mid-trabecular 

 islands of large lacunae and low-densit\' matrix ( Fig. 7 ) . 



The most extensive zones of mid-trabecular low density were 

 registered in birds treated with vitamin D and Para-Thor-Mone com- 

 bined ( Fig. 8 ) . 



Alpharadiographs of mineralized sections (Figs. 9 and 10) re- 

 corded on a high-contrast emulsion revealed a loss of minerals 

 parallel to the loss of organic density in mid-trabecular portions of 

 the vitamin D-treated birds, and a considerably more extensive low 

 densitv in the xitamin D-Para-Thor-Mone group. 



X-ray microradiographij produced comparable results. 



Norethandrolone. Alpharadiographs of the demineralized tibia of 

 norethandrolone-treated chicks ha\e previously been described 

 (Belanger and Migicoxskv, 1961). Staining with toluidine blue and 

 also with a combination of neutral red and fast green ( Fig. 16 ) re- 

 vealed that some of the hypertrophic osteocytes actually acquired 

 all the staining behavior of cartilage cells and were also apparently 

 responsible for a large concentration of acid mucopolysaccharides 

 in the surrounding matrix. 



Rats 



Toluidine blue. EDTA-demineralized bones revealed considera- 

 ble variations among the four groups. The diaphysis of the control 

 animals (Fig. 13) contained mostly small osteocytes. However, a 

 band of larger cells was located al^out midway between the perios- 

 teum (Fig. 13, P) and the border of the central marrow cavity. The 

 hypertrophic osteoc\ tes in that area had a metachromatic-staining 

 cvtoplasm when stained with toluidine blue. The immediate border 

 of their lacunae ( capsule ) exhilMted the same tinctorial property. 



Rats injected with Para-Thor-Mone (Fig. 14) showed an increase 

 in the number of h\'pertrophic and metachromatic osteocytes. These 

 extended from the center of the diaphysis inward and consequently 

 were the older cells. The organic matrix was lightly basophilic around 

 most of these hypertrophic osteocytes (Fig. 14). Elsewhere in the 



