RAREFYING DISEASE OF THE SKELETON 



397 



Fig. 5C. Photomicrogiaph showing a typical area of osteoporotic interstitial 

 bone. The lacunae are enlarged, spherical, smooth-walled, and empty (arrow). 

 The broad lines between the lamellae represent thick layers of metachromatic- 

 staining cement substance, presumably deposited on exposed sin-faces of 

 matrix under conditions in which the rate of bone formation is abnormally 

 low. (x approx. 400.) 



an osteoporotic required to build a new osteon. However, many 

 osteons stopped growing and developed a sclerotic inner margin 

 before they were three-fourths closed in aged and osteoporotic in- 

 dividuals. 



The life expectancy of an osteocyte in an outer lamella ( the area 

 of the osteon farthest from the central blood vessel ) in aged persons 

 with osteoporosis and chronic circulatory insufficiency is probably 

 not more than 12 weeks. Further investigations with the aid of con- 

 tinuous administration of oxytetracycline are in progress to meas- 

 ure this interval in both nonosteoporotic and osteoporotic subjects. 



