44 



FOURTH LECTURE. 



able dimensions in many mature cartilages (Fig. 44, a), so 

 that we may meet with enormous capsules of O. I to 0.2 mm. 

 with whole troops of contained cells. Not unfrequently, how- 

 ever, this exuberant increase foretells the approaching disap- 

 pearance of the tissue. 



Depositions of fat in the cell body, especially in the vicinity 

 of the nucleus, then form very common transformations. 

 They may begin very early. Later, the nucleus frequently 

 becomes invested by a coherent spherical shell of fat (Fig. 



44). 



A subsequent metamorphosis of the apparently homoge- 

 neous intercellular substance into firm, delicate fibrillae, which 

 resist acetic acid, is frequently observed ; this is especially 

 constant in the interior of old costal cartilage (Fig. 44). 



Calcification is, finally, a quite frequent occurrence in car- 

 tilage undergoing retrogression. Dark granules or crumbs 



of lime salts surround the cells or cell 

 groups, at first in an areolated man- 

 ner. They increase in quantity ; the 

 whole intermediate substance acquires 

 a dark, granular appearance ; the cap- 

 sules also become implicated in the 

 deposition, and finally all is black and 

 opaque ; only the cells glisten through 

 as bright gaps. The older investi- 

 gators could not master this. Now- 

 adays we readily succeed by the aid of decalcification 

 with chromic or lactic acids. 



This calcified cartilage is, however, far from being or from 

 becoming bone. We shall hereafter return to this subject. 



Hyaline cartilage substance constituted originally almost 

 our entire skeleton, with the exception of the portions form- 

 ing the vault of the cranium and the bones of the face. This 

 is the transitory cartilage. Remains of the same form the 

 articular and costal cartilages and others. Other masses of 

 cartilage have nothing to do with the skeleton. To these 

 belong the larger cartilages of the larynx, and the cartilage 



Fig. 45. — Commencing calcifi 

 cation ot hyaline cartilage. 



