STRUCTURE AND COMPOSITION OF CARTILAGE. 



155 



52. 



food is scanty during the winter, usually exhibit a strong tendency to such an 

 accumulation, during the latter part of the summer, when their food is most 

 rich and abundant ; and the store thus laid up is consumed during the winter. 

 This is particularly evident in the hybernating Mammalia, which take little or 

 no food during their seclusion. Fat appears to be deposited, only where there 

 is an excess, in the alimentary matter introduced into the body, of non-azo- 

 tized compounds which may be converted into it. But the ingestion of a large 

 quantity of these in the food, is by no means sufficient for the production of 

 Fat ; for they may not be absorbed into the vessels ; and, if absorbed, there 

 may be a want of power to generate Adipose tissue, so that they would ac- 

 cumulate injuriously in the blood, if not drawn off by the Liver. Hence 

 some persons never become fat, however large the quantity of oily matter 

 ingested ; and it is in such persons, that the pendency to disorder of the Liver 

 from over-work is most readily manifested ; hence they are obliged to abstain 

 from the use of fat-producing articles of food. 



187. In Cartilage, also, the simple cellular structure is very obviously re- 

 tained, and frequently exists alone ; although in some forms of this tissue, it 

 is united with the fibrous, or partly 

 replaced by it. In all, however, the 

 early stage of formation appears to 

 be the same. The structure origi- 

 nates in cells, analogous to those of 

 which the rest of the fabric is com- 

 posed ; but between these cells, a 

 larger quantity than usual of hyaline 

 or intercellular substance is depo- 

 sited; and the amount of this sub- 

 stance continues increasing, simul- 

 taneously with the bulk of the cells. 

 The original cells are pushed far- 

 ther and farther from one another ; 

 but new cells arise between them 

 from germs which are contained in 

 the hyaline substance. The first 

 cells frequently produce two or more 

 young cells from their nuclei ; and 

 thus it is very common to meet with 



groups of such cells or corpuscles, consisting of two, three, or four. The 

 varieties in the permanent Cartilages principally depend upon the degree of 

 organization, which subsequently 

 takes place in the intercellular sub- 

 stance. If a mass of Fibres, analo- 

 gous to those of the fibrous mem- 

 branes ( 138), should originate in 

 it, the Cartilage presents a more or 

 less fibrous aspect; in some instan- 

 ces the Fibrous structure is deve- 

 loped so much, at the expense of 

 the Cells, that the latter disappear 

 altogether, and the whole structure 

 becomes fibrous. Sometimes the 

 fibres which are developed, are 

 rather analogous to those of the 

 Elastic tissue ( 140) ; these are dis- 



posed around the cells, forming a Fibro . C artiia ge , showing disposiuon of 



kind of network, in the areolae of cartilage cellB> in areote of fibrous tissue . 



Section of the Branchial cartilage of Tadpole ; a f 

 group of four cells, separating from each other; 6, 

 pair of cells in apposition: c. c, nuclei of cartilage 

 cells ; rf, cavity containing three cells. 



Fig. 53. 



