FIBRO-CARTILAGE. 105 



the distribution and occurrence of cartilaginous tissue, in the 

 case of Cephalopods and Molluscs, by Lebert and Robin,* and 

 by Claparede and Semper.-f- Before we pass to the considera- 

 tion of fibro-cartilage, the fibrous transformation of the matrix 

 of hyaline cartilage must first be mentioned, which occurs 

 sooner or later after the commencement of extra-uterine life. 

 This appearance is particularly obvious in the costal and laryn- 

 geal cartilages.:}: On examining a transverse section of the 

 costal cartilages of an adult, striae or rings may almost always be 

 observed, distinguished by their white and opaque appearance, 

 and the peculiar lustre they possess. Microscopic examination 

 shows that the matrix at these points is composed of rigid 

 closely approximated parallel fibres. These are unbranched, and 

 when subjected to the action of acetic acid, do not disappear, 

 but pass uninterruptedly into the surrounding non-fibrous 

 portion of the matrix. If such a section be broken up with 

 needles, the parallel fibres break at various points of their 

 course, and these project to a variable extent from the fractured 

 surface ; the cause of this development of fibres in hyaline 

 cartilage is not accurately known. Coincidently with the for- 

 mation of these fibres in cartilage, a process of proliferation 

 usually occurs, so that the cells lie closely compressed in great 

 masses in the matrix. 



FIBRO-CARTILAGE. True fibro-cartilage differs from hyaline 

 cartilage in its matrix, presenting fibres of variable number, 

 form, and chemical characters. The alteration of the index of 

 refraction occasioned by the layers of delicate fibres and their 

 interstices, and in some fibro-cartilages the small degree of 

 translucency possessed by the several fibres, makes even fine 

 sections of these cartilages, when compared with hyaline 

 cartilage, appear on examination much darker and more 

 opaque. By direct light, on the other hand, the fibro-cartilage 



* Miiller's Archw, 1846, p. 129. 



f Zeitsclirift fur wissenschaftliche Zoologie, Band ix., p. 274. 

 | Bonders, Hollandische Beitrage, Band i., p. 258. H. Meyer, Miiller's 

 Archiv, 1846, p. 292. 



Donders, Mever, loc. cit. 



