156 ON THE ELEMENTARY PARTS OF THE HUMAN FABRIC. 



which they lie; and this kind of cartilage may be termed the elastic or 

 reticular. The primitive cellular organization is for the most part retained 

 in the ordinary articular cartilages,* the cartilaginous septum narium, the car- 

 tilages of the alae and point of the nose, the semilunar cartilage of the eye- 

 lids, the cartilages of the larynx (with the exception of the epiglottis), the 

 cartilage of the trachea and its branches, the cartilages of the ribs (in Man) 

 and the ensiform cartilage of the sternum ; and it is seen also in the tempo- 

 rary cartilages, or those which are destined to undergo ossification. The 

 fibrous structure is seen in all those Cartilages, which unite the bones by 

 synchondrosis ; this is the case in the vertebral column and pelvis, the 

 cartilages of which are destitute of corpuscles, except in and near their cen- 

 tres. In the lower Vertebrata, however, and in the early condition of the 

 higher, the fibrous structure is confined to the exterior, and the whole interior 

 is occupied by the ordinary cartilaginous corpuscles. The reticular structure 

 is best seen in the epiglottis and in the concha aims : in the former of these, 

 scarcely any trace of cartilage-cells remains ; in the latter, the fibrous net- 

 work disappears by degrees towards the extremity of the concha, and the 

 structure gradually passes into the cellular form.t 



a. The substance that gives to the Cellular Cartilages their peculiar character, has received 

 the designation of Chondrine. It bears much resemblance to ordinary Gelatine, but requires 

 longer boiling in water for its solution; the solution fixes on cooling, like that of gelatine; 

 and when it becomes dry by evaporation, it has the appearance of solid glue. Choudrine 

 is not precipitated, however, by tannic acid; on the other hand, it gives precipitates with 

 acetic acid, alum, acetate of lead, and proto-sulphate of iron, which do not disturb a solution 

 of Gelatine. That the Chondrine obtained by boiling Cartilage is an actual component of 

 that tissue, and is not a product of the operation, appears from the agreement between its 

 elementary composition and that of cartilage, when analyzed by combustion. According to 

 Mulder, the proportions of the elements, as deduced from the definite compound which 

 Chondrine forms with Chlorine, are 32 C, 26 H, 4N, 14 0, with l-10th of an equivalent of 

 Sulphur. Chondrine agrees much more nearly with the proteine-compounds, in its element- 

 ary composition, than does Gelatine ; and may be considered as a sort of intermediate stage 

 between the two. Chondrine is not obtainable from any of the Fibro-cartilagcs ; these 

 yield gelatine, on boiling, exactly similar to that of the tendons. The Elastic cartilages, 

 after being boiled for several days, yield a small quantity of an extract, which does not form 

 a jelly, but which has the other chemical properties of Chondrine. The cartilage of Bone, 

 before ossification, yields only Chondrine ; after ossification, however, it affords only Gelatine ; 

 and it is curious that, even when bony deposits take place in the permanent cartilages, the 

 ossified portion contains ordinary Gelatine in the place of Chondrine. Many of the carti- 

 lages naturally contain a large proportion of mineral matter ; in the costal cartilages, frac- 

 tures in which are generally repaired by osseous substance, from 3 to 7 per cent, of ash is 

 left by calcination. This contains a large proportion of the carbonate and sulphate of soda, 

 together with carbonate of lime and a small proportion of phosphate ; as age advances, the 

 phosphate of lime predominates, and the soluble compounds diminish. 



188. Cartilage (at least in its simplest form) is nourished, without coming 

 into direct relation with the Blood through the medium of blood-vessels; the 

 cellular Cartilages not being penetrated by vessels in the healthy state; al- 

 though in certain diseased conditions they become distinctly vascular. They 

 are, however, surrounded by Blood-vessels ; which form large ampullae or 

 varicose dilatations at their edges or on their surfaces (Fig. 54): and from 

 these the Cartilages derive their nourishment by imbibition ; in exactly the 

 same manner as the frond of a Sea-weed (the structure of which is alike cel- 

 lular) draws into itself the requisite fluid from the surrounding medium. In 

 the thicker masses of cartilaginous tissue, however, such as the cartilages of 



* The articular cartilages, at the points win-re tendons arc implanted into them, have all 

 the characters of fibre-cartilage; the fibres nf the temlun beiuu; spread through, the intercel- 

 lular substance of the cartilage, for some distance, and gradually coalescing with it. 



"j" See Mr. Toynbee's Memoir on the Non-Vascular Tissues, Phil. Trans. 1841. 



