538 BELANGER, ROBICIION, MIGICOVSKY, COPP, VINCENT 



empt\ or showed osteocytes which were apparently degenerate 



(Fig: 12). 



Periodic acicl-Schijf. Sections of EDTA-deniineraHzed bone re- 

 vealed a more intense and less uniform distribution of PAS-stained 

 material than sections demineralized in nitric-ethanol. 



The bones of rachitic and Para-Thor-Mone-treated birds were the 

 least stained. The trabeculae revealed an unstained or poorly stained 

 band at the periphery (osteoid, prebone) and a more intensely 

 stained axial region, containing the large osteocytes. The osteoblasts 

 and osteocytes were generally weakly stained if at all. 



The vitamin D-treated chicks and those which received Para- 

 Thor-Mone along with vitamin D showed a generally more intense 

 PAS stain. The trabeculae contained three zones which were un- 

 evenly distributed: a peripheral weakly stained border, then a more 

 or less wide band of higher intensitv, and eventually a mid-trabecu- 

 lar island of more weakly stained tissue around the hypertrophic 

 osteocvtes. These zones were less apparent in birds which received 

 only vitamin D. In some areas, the central clear islands contained 

 masses of PAS-stained material of irregular shape and size. 



Sections stained bv the Alcian bluc-PAS method showed concen- 

 trations of alcianophilic material in the large osteocytes and adjacent 

 matrix of the mid-tral)ecular region, particularly evident in the Para- 

 Thor-Mone-vitamin D group and in sections which had l)een de- 

 mineralized in EDTA. 



Unstained sections under phase contrast revealed marked differ- 

 ences between the various groups at the accretion sites of bone and 

 cartilage. These will be reported elsewhere. However, no charac- 

 teristic variations in pattern could be detected within the older 

 regions. 



Alpharadiographs. Alpharadiographs of demineralized sections 

 produced patterns of varied densities. In trabeculae of rachitic birds 

 (Fig. 5), the matrix appeared almost uniformly dense with appar- 

 ently empty holes marking the lacunae, and among them only a few 

 of larger size could be seen ( Fig. 5 ) . 



In birds treated with Para-Thor-Mone (Fig. 6) the larger lacunae 



