LECTURE II. 



Fia 22< 



spindle-shaped ones, as, for example, with great regula- 

 rity in the immediate neighbourhood of the articular 



surfaces. The nearer, in the 

 examination of articular car- 

 tilage, we approach to the 

 free surface (Fig. 22, a,) the 

 smaller do the cells become ; 

 and, at last, nothing more is 

 seen but small, flatly lenti- 

 cular bodies, the substance 

 intervening between which 

 sometimes presents a slightly 

 striated appearance. Here, therefore, without the tis- 

 sue's having ceased to be cartilage, a new type displays 

 itself, which we much more regularly meet with in pure 

 connective tissue, and hence the idea might easily arise 

 that articular cartilage is invested with a special mem- 

 brane. This is, however, not the case, for there is no 

 synovial membrane spread over the cartilage, but its 

 boundary towards the cavity of the joint is everywhere 

 formed of cartilage itself. The synovial membrane only 

 begins where the cartilage ceases at the edge of the 

 bone. On the other hand, we see that at certain points 

 the cartilage passes directly into forms in which the cells 

 become stellate, and the way is paved for their final 

 anastomosis ; ultimately, spots are met with at which it 

 is no longer possible to say where the one cell ends and 

 the other begins, inasmuch as they communicate so 

 directly one with another that it is impossible to detect 

 a line of separation between their membranes. When 



Fig. 22. Perpendicular section through the growing cartilage of a patella, a. The 

 articular surface, with spindle-shaped cells (cartilage-corpuscles) disposed in layers 

 parallel to it. 6. Incipient proliferation of the cells, c. Advanced proliferation ; 

 large, roundish groups within the enlarged capsules a continually increasing num- 

 ber of round cells. 50 diameters. 



