28 



NORMAL HISTOLOGY. 



fasciae, the cornea and the dura mater. In the dense connective tissue the 

 ground-substance often contains a system of definite interfascicular lymph- 

 spaces, which, in suitably stained preparations, appear as irregularly stellate 

 clefts (Fig. 30) that form, by union of their ramifications, a network of chan- 

 nels for the conveyance of the tissue-juices throughout the dense structure. 

 Where definite, as in the cornea or central tendon of the diaphragm, these 

 spaces are almost, if not completely, filled by the stellate connective tissue cells 

 which they enclose. A somewhat similar, although modified relation, is to 

 be noted in the bursae, tendon- sheaths and smaller joint-cavities, in which 

 the free inner surface is often clothed by an incomplete covering of branched 

 or plate-like connective tissue cells. 



Tendon, the densest form of fibrous tissue, consists essentially of par- 

 allel bundles of white fibres. The individual fibres, held together by cement 

 substance, are assembled as comparatively large primary bundles which, in 



Blood-vessel within septa 

 enclosing tertiary bundles 



FIG. 39. Longitudinal section 

 of tendon from young subject ; 

 the tendon-cells are seen in 

 profile between the bundles of 

 fibrous tissue. X 300. 



Spaces occupied by tendon-cells 



FIG. 40. Transverse section of a tendon, showing the grouping 

 of the tendon-tissue into primary, secondary and tertiary bundles. 

 X8o. 



turn, are united by the interfascicular connective tissue and grouped into 

 secondary Bundles. The latter, invested by a delicate sheath of areolar 

 tissue and partially covered by plate-like connective tissue cells, are held 

 together by partitions or septa of areolar tissue which are extensions of the 

 general connective tissue envelope that surrounds the entire tendon. The 

 larger septa surrounding the tertiary bundles support the meagre blood- 

 vessels and nerves and afford a path by which these gain the interior of 

 the tendon. The blood-vessels, however, never penetrate the individual 

 bundles, but are confined to the areolar tissue which invests them. The 

 relations of the nerves to the tendon-tissue are described with the Nerve- 

 Endings (page 85). The primary bundles consist exclusively of white 

 fibres and the cement-substance, which contain collagen and tendo-mucoid 

 respectively. A few delicate elastic fibres are sometimes distinguishable in 

 the vicinity of the tendon-cells. The latter are the equivalents of the usual 

 connective tissue cells, but so modified by the disposition of the bundles to 

 which they conform that they assume distinctive shapes. The tendon-cells 

 occur in rows within the clefts between the primary bundles, upon the surface 



