RESORPTION WITHOUT OSTEOCLASTS (OSTEOLYSIS) 549 



Humans 



A variety of pathological material was obtained and submitted to 

 x-ray microradiography, alpharadiography, and histochemical stain- 

 ing. The results were in accord with those of our animal series. 



A specimen of bone with spontaneous fractures from a case of 

 parathyroid adenoma revealed the presence of enlarged confluent 

 lacunae accompanied by decreased density of matrix ( Fig. 27 ) . 



A biopsy from a patient suffering from osteogenesis imperfecta 

 also showed, in x-ray microradiographs of mineralized sections, en- 

 larged confluent lacunae and adjacent low density of matrix (Fig. 

 28). 



Specimens of neoplastic bones (osteogenic sarcoma, Ewing's sar- 

 coma) and specimens of Paget bone revealed similar instances. In 

 this latter case, however, the density records are complex and will 

 be the subject of a further report. 



Discussion 



The Normal Phenomenon 



It appears from the present series of experiments that there are in 

 chicks, rats, and dogs osteocytes of two different types. The small 

 osteocijtes (Figs. 11 and 13) are predominant near the formative 

 surfaces. These cells have a cytoplasm which stains weakly with 

 toluidine blue. The organic matrix surrounding the small osteocytes 

 has a high density as demonstrated by alpharadiography (Fig. 22); 



Fig. 21. A portion of compact bone (tibia) of a control dog showing in- 

 terstitial lamellae of variable density and lacunae of different sizes. X-ray 

 microradiograph. (X 144.) 



Fig. 22. Compact bone of control dog, showing alternate bands of high 

 and low density, lacunae of different sizes, and small low-density areas 

 (arrows) around some of the larger lacunae. Alpharadiograph of demineralized 

 section. (X 88.) 



Fig. 23. A portion of compact bone (skull) of an EDTA-infused dog. 

 Large, confluent resorption lacunae. X-ray microradiograph. ( X 144.) 



Fig. 24. Alpharadiograph of a comparable demineralized specimen. The 

 immediate vicinity of the haversian canal shows high density and enlarged 

 lacunae. Islands of loss of organic density correspond to those of low salt con- 

 centration in Fig. 3. ( X 144. ) 



