CARTILAGE. 317 



body are, in contradistinction from these, called permanent carti- 

 lages e. g. articular cartilages, costal cartilages, &c. 



Development of Cartilage. 



True cartilage originates in cells not distinguishable at first from 

 those from which the other tissues are developed. Between these 

 cells a hyaline substance is deposited, which, on being boiled, be- 

 comes chondrine ; and which usually increases simultaneously with 

 the bulk of the cells. Thus, the original cells are pushed further 

 and further asunder. 



But new cells are also produced from germs in the hyaline sub- 

 stance ; while at the same time the original ones are multiplied by 

 bipartite and tripartite subdi- 

 vision (p. 126). Thus, it is 

 very common to meet with 

 groups of two, three, or four 

 cells (or more) in a single ca- 

 vity, as shown by Fig. 204. 



If the intercellular substance 

 consist of collagenous fibres, 

 a fibro-cartilage results. And 

 sometimes the cells entirely 

 disappear, and the whole re- 

 maining maSS is fibrOUS. The Section of the branchial cartilage of tadpole, a. 

 _, .. Group of four cells, separating from each other, b. 



nbres are developed m the Pa ir of ceiis in apposition, c, c. Nuclei of cartilage- 

 external portions first. When cells - d - Cavity ^taining-three cells. 



elastic fibres are developed from the intercellular substance, a reti- 

 culated cartilage results. 



The growth of cartilage is secured both by the reduplication of 

 the cells, and the increase of the intercellular substance. The 

 plasma doubtless permeates the intercellular substance, and the 

 peculiar fluid, before alluded to, is probably a modified plasma, and 

 contains the elements for the nutrition of the cartilage. The car- 

 tilage-cavities of the new-born infant are three or four times as 

 numerous as in the foetus of four months; but the intercellular 

 substance is now double the bulk of the cavities, while at the latter 

 period it hardly exceeds the latter at least in the costal cartilages. 

 After birth, the cavities (and contained cells) and the intercellular 

 substance, increase in pretty nearly an equal ratio. According to 

 Harting, the cavities (and contents) are 8 to 12 times larger in the 

 adult than in the infant at birth. 



