TISSUES OF THE BODY. 



181 



Connective-tissue cartilages possess vessels, "but only in small num- 

 ber ; but as to the presence of nerves, we are as yet unable to state any- 

 thing certain. 



Among them the cartilages of the eye-lids may be reckoned, of which 

 the upper appears to be richer in cells than 

 the lower, which has but few of the latter 

 ( Gerlach) ; further, the c. triticece of the 

 larynx, which may, however, consist of hya- 

 line substance (Rheiner) ; then the c. inter- 

 articulares, as well as the so-called labra 

 cartilaginea of certain joints, with the car- 

 tilaginous knots found in tendons. As a 

 rule, it seems to be part of the composite 

 character of the tibro-cartilages, that struc- 

 tures formed of pure connective-tissue may 

 be transformed at points into the varieties 

 of the tissue in question by the imbedding of cartilage cells, 

 is the case in the terminal portions of tendons where they are inserted 

 into bone, as well as many parts of their sheaths (Kolliker). 



Finally, fibro-cartilage, springing, moreover, continuously from the 

 hyaline, appears in the symphyses and so-called half-joints, which have 

 their origin in the liquefaction of the central portion of solid masses con- 

 necting bones (Luschka). 



Among the latter, those most worthy of consideration are the sym- 



6 



Fig. 172. Diagram of a vertebral 

 symphysis divided vertically. At 

 o, the pulpy centre ; at 6, tlie 

 fibrous ring; at c, the cartilagin- 

 ous covering of the body of the 

 vertebra ; d, the periosteum. 



This 



, Fig. 173. Vertical section through the bodies, the last dorsal and first lumbar 



vertebra of a human embryo at ten weeks. Body with calcified carti- 

 laginous tissue, a ; and unchanged, b ; at c the fibrous ring developing, con- 

 sisting of elongated cells (?), and with a cavity containing transparent 

 cells at d, which becomes the pulpy nucleus of the infant 



physes of the vertebra, so frequently the subject of investigation, the so- 

 called ligamenta intervertebralia, about which Luschka has imparted to 

 us such valuable information. 



They present themselves as solid connecting plates between the bodies 

 of the vertebra (fig. 172), taking their rise continuously (at least at their 

 circumference) from a layer of hyaline cartilage which clothes the surfaces 

 of the bone (c). They each consist of a fibrous ring externally (&), 



