VI. EFFECTS OF DEFICIENCY 



245 



with hematoxylin, but later, as the degenerative process continues, they 

 lose their staining ability entirely. 



The degeneration of cartilage cells may progress to the formation of 

 actual areas of necrosis. Although found most frequently in rats, such areas, 

 hemispherical and circumscribed, have also been described in humans. 

 Occasionally such degenerative and necrotic areas may dominate the patho- 

 logic picture. 



Fig. 21. Large capillary tuft invading the cartilage. Severe rickets. Calcium 

 deficiency; large masses of uncalcified osteoid; connective tissue marrow. 



We have already noted that during the ricketic process the proliferation 

 of new cartilage cells continues while the formation of bone is retarded or 

 stopped. This, together with the invasion of this zone by large vascular 

 tufts (Fig. 21), results in the formation of a wide zone, soft and radiotrans- 

 lucent, between the shaft of the bone and the epiphysis. This zone, known 

 as the metaphysis, is an entirely abnormal area in which are scattered all 

 the elements of the pathologic picture of rickets, including large vascular 

 clumps, which enter the area from all sides, masses of cartilage broken up 

 into cartilaginous and osteoid trabeculae, bizarre cartilage cells, occasional 

 mineral salt deposits representing evanescent attempts at healing, and foci 

 of complete degeneration (Fig. 22). In this region we may note evidence 



