CAETILAGE. 



mostly directed Tertically. {Fio;. 43.) It is well known that articular 

 cartilages readily break in a direction perpendicular to their surface. 



Fig. 43. 



Fig. 44. 



m^ 



^fffm 



'^ / 



=.^:^L 



Vol 



[^ 



'J 





- O^ 



^'V J 



l; 



^'*<&:±^ '•'•' 



Fig. 43. — Vertical Sectiox of Articular Cartilage op the Head of the Hujierus. 

 A deep iwrtiou near the bone. Magnified 400 diameters. 



Fig. 44. — A Thin Layer peeled off froji the Surface of the Cartilage op the 

 Head of the Humerus, showing Flattened Groups op Cells. 

 Tlie shrunken cell-bodies are distinctly seen, Init the limits of the capsular cavities 

 where they adjoin one another are but faintly indicated. Magnified 400 diameters. 



and the surface of the fracture npjiears to the naked eye to be striated 



in the same direction, as if they had a columnar structure ; this has been 



Pi„_ 45_ ascribed to the vertical 



^ arrangement of the 



rows of cells, or to a 



,/: latent fibrous or col- 



^ ^-.-"' : umnar disposition of 



'^;r\\ __^j the substance of the 



-r_^' i\ jfi matrix (Leidy). It was 



JO) (Qj i formerly held that the 



Vl^ 4 free surface of articular 



I cartilage is covered 



] with epithelium, but 



,,; ; ; no such covering really 



-'--'■■:'■ ,> exists. It is easy, no 



^//■'^' doubt, to peel off a 



thin film from the 



surface of the cartilage 



of the head of the 



humerus or femur ; 



but this superficial 



layer is really part of 



the cartilage, and its 



intermediate matrix are not to be 



Fi?. 4i 



-1;"1;i.i;k 



Arxklj-ah Cartilage showing 

 Transition of Cartilage Cells into Connective- 

 Tissue Corpuscles op Synovial Membrane. From 

 HEAD OP Metatarsal Uone, Human. About 340 

 diameters. 



a, ordinary cartilage cells ; l,h, with branching pro- 

 cesses. 



broad patches of cells with the 



