98 



THE TISSUES 



interlace in such a manner as to leave openings in the membrane. 

 Hence the term ''fenestrated membrane." They have been re- 

 cently described as consisting of a central layer composed of elastin, 

 staining with magenta, and on either side a thin, transparent sheath 

 unstained by magenta. This is seen to correspond to Mall's de- 

 scription of the structure of the elastic fibre. Only the middle of 

 these layers is fenestrated. 



RETICULAR TISSUE 



Reticular connective tissue is a form of fibrillar connective 

 tissue. It consists of extremely delicate fibrils with no ground 



Fig. 47. — Reticular Tissue from a Human Lj^mph Node. (Teciiuic, 13, p. 101.) a, 

 Reticular connective tissue, in the meshes of which are suspended b, leucocytes, and c, ( 



lymphocytes. The reticular connectiv^e tissue is present also in the more dense 

 lymphatic tissue seen in the lower part of the figure, but is not visible on account of the 

 closely packed cells. 



! 



substance. The fibrils are grouped in larger or smaller bundles I 

 which form a network or feltwork enclosing spaces, thus constitut- j 



