54 



TEXT-BOOK OF PHYSIOLOGY. 



Yellow fibre-cartilage, the ground substance of which is pervaded 

 by opaque, yellow elastic fibers, which form, by the interlacing 



of their branches, a complicated 

 network, in the meshes of which 

 are to be found the usual cor- 

 puscles. (See Fig. 13.) As 

 these fibers are elastic, they 

 impart to the cartilage a very 

 considerable degree of elas- 

 ticity. Yellow fibre-cartilage 

 is well adapted, therefore, for 

 entering into the formation of 

 the external ear, epiglottis, 

 Eustachian tube, etc. struc- 

 tures which require for their 

 functional activity a certain 

 degree of flexibility and elas- 

 ticity. 



Osseous Tissue. Osseous tis- 

 sue, as distinguished from bone, is 

 a member of the connective-tissue 

 group, the ground substance of 



which is permeated with insoluble lime salts, of which the phosphate 

 and carbonate are the most abundant. Immersed in dilute solutions 

 of hydrochloric acid, they can be converted into soluble salts and dis- 



FIG. 12. FROM A HORIZONTAL SEC- 

 TION OF THE INTERVERTEBRAL 

 Disc OF MAN. g. Fibrillar con- 

 nective tissue. 2. Cartilage-cell 

 (nucleus invisible), k. Capsule 

 surrounded by calcareous gran- 

 ules. X 240. 



) i 



FIG. 13. ELASTIC CARTILAGE. X 240. i. Portion of section of vocal process (ante- 

 rior angle) of arytenoid cartilage of a woman thirty years old; the elastic substance 

 in the form of granules. 2 and 3. Portions of sections of epiglottis of a woman 

 sixty years old; a fine network of elastic fibers in 2, a coarser network in 3. z. 

 Cartilage-cell, nucleus not visible; k, capsule. 



solved out. The osseous matrix left behind is soft and pliable. 

 When boiled, it yields gelatin. 



A thin, transverse section of a decalcified bone, when examined 

 microscopically, reveals a number of small, round, or oval openings, 



