346 



DISEASES OF THE FEET. 



the inflammatory action ; its vessels are injected, its surface 

 presenting a red streaky appearance ; it becomes slightly, but 



lit 03 1 H, ( i 



Flu 63 'allows the gradual ejection of the ti^^ius of tliL c'irtilij,'-e at the ulcerated 

 spots. In the centre of the hollow the superncial parts of tlie cartilage liave disap- 

 peared, and the deeper parts are undergoing degeneration, becoming irregular, 

 shrivelled, losing their walls, and discharging their contents. — (After Eedfern.) 



Fig. 64. — Vertical section of cartilage, showing the notches produced by burst- 

 ing of the cells, and the fibrous and granular mass on the free surface. — (Redfern ) 

 This figure very fairly illustrates the change in the navicular cartilage at an 

 early stage of its conversion into a finely granular calcareous substance. 



never much thickened; in very 

 chronic cases its free surface 

 becomes involved in the gene- 

 ral adhesive process, and united 

 to the tendon and bone. 



The changes in the cartilage 

 are the same as when the carti- 

 lage of incrustation is inflamed 

 in an articulation (see Chapter 

 XL) ; it is either removed from 

 the surface of the boneby ulcera- 

 tion, or converted into fibrous 

 tissue or a calcareous material. 

 The supposition that the sur- 

 FiG. 65 shows the superficial cells of face of tliis Cartilage is uaturally 

 ?4„S^.'„Vfit;Str'„rrfr,L" covered by a membrane is not 



borne out by microscopic inves- 

 tigation ; tlie supposed membrane being nothing more than 

 the cartilage corpuscles, which are flattened upon the free sur- 



iS^iSfe-v 



