CANALS IN THE SEMI-LUNAR CARTILAGES. H7 



fibro-cartilage, and it is displayed with unusual distinct- 

 ness and clearness. Vessels are almost entirely wanting 

 in these cartilages, but in ex- 



PlQ. 86. 



change they contain a system 

 of tubes of rare beauty. On 

 making a section, we see that 

 the whole is in the first place 

 mapped out into large divi- 

 sions, exactly like a tendon ; 

 these are subdivided into 

 smaller ones, and these are 

 pervaded by a fine, stellate 

 system of tubes, or, if you 

 will, of, cells, inasmuch as the 

 notion of a tube and that of a 

 cell here quite coincide. The 

 networks of cells which here 

 form the system of tubes, terminate externally in the septa 

 bounding the individual divisions, and we here see in close 

 proximity considerable collections of spindle-shaped cells. 

 In these cartilages, too, the whole mass of tissue is only 

 connected by its exterior with the circulatory system ; 

 everything that penetrates into the interior must pass 

 by a very circuitous route through a system of canals 

 with numerous anastomoses, and the nutrition of the in- 

 ternal parts is altogether dependent upon this mode of 

 conveyance. The semi-lunar cartilages are structures of 

 considerable extent and great density, and as they are 

 entirely dependent for their nutrition upon this ultimate, 

 minute system of cells, we have in them, much more 



Fig. 36. Section from the semi-lunar cartilage of the knee-joint of a child, a. 

 Bands of fibres, with spindle-shaped, parallel and anastomosing cells (seen in longi- 

 tudinal section), b. Cells, forming a network, with broad, branching, and anasto- 

 mosing canaliculi (seen in transverse section). Treated with acetic acid. 350 

 diameters. 



