IX.] THE FIBRO-CARTILAGES. 153 



picro-sulphuric acid (twenty-four hours). The hardening is com- 

 pleted in the various strengths of alcohol. Tease it with needles 

 in Farrant's solution. 



(a) Observe the fibrous matrix, consisting of very fine, wavy 

 unbranohod fibrils (fig. 116), and between them oval 

 nucleated cells, each one with a 

 distinct thick hyaline capsule. 

 In some of the latter, concentric 

 rings indicating the deposition of 

 successive capsules, may be seen. 



(b.) The bundles of fibres run 

 in various directions, and each 

 fibril is unbranched. The cells 

 with thick capsules are not 

 very numerous, and lie either 

 singly or in groups of two or 

 three between the fibres. 



3 V Another Method. The 

 cells' of this cartilage do not liu-< ; u> 



stain very readily, but the follow- FIG. 116. From Human Intervertebral Disc. 



., , . , ,, m. Matrix or fibrous ground-substance; 



ing method gives good results : c . Cartilage-cell ; k. Capsule surrounded 



-Harden the cartilage-small j[J* S^!? x ""* 

 pieces for a day or so in 



Kleinenberg's fluid (p. 30), and after washing the pieces free from 

 the picro-sulphuric acid, place them for several days in borax- 

 carmine, and stain them en masse. Concentrate the pigment in 

 the cells by placing the pieces in acid alcohol for twenty-four hours 

 (\\ 65). Sections can be "made either by freezing or embedding in 

 paraffin. The cells are stained bright red. 



B. Yellow Fibro-Cartilage. (i.) Harden the epiglottis of a sheep, 

 dog, or cat for forty-eight hours in absolute alcohol. 



(ii.) Harden a part of .the ear of a pig in a saturated solution of 

 picric acid for twenty-four hours. Wash away the picric acid with 

 alcohol, and in the various strengths of alcohol complete the 

 hardening. 



By freezing make sections of the epiglottis and ear. 



4. Epiglottis. Stain a section in picro-carmine and mount it in 

 Farrant's solution. 



(.) (L) Neglecting the stratified epithelium and glands which 

 are present, observe the perichondrium (fig. 1 1 7, c,/), embracing the 

 mass of cartilage, and firmly adherent to the latter, which has a 

 fibrous, yellow-stained matrix, studded with cells stained red 

 embedded in it. The mass of cartilage may appear to be interrupted. 

 or it may even be perforated. 



(b.) (H) Observe the perichondrium, composed of connective 

 15 



