AREOLAR TISSUE. 41 



like the cells of an epithelium ; the cell-spaces have in all cases a similar 

 arrangement. (2) Plasma-cells of Waldeyer (fig. 42, p), which are com- 

 posed of a soft much-vacuolated protoplasm, rarely flattened, but other- 

 wise varying greatly in shape and size. (3) Granule-cells (g), usually 

 spheroidal or ovoidal in shape, and formed, like the plasma cells, of soft- 

 protoplasm, but thickly occupied with albuminous granules, which are 

 deeply stained by eosine and by most aniline dyes. Migratory lymph- 

 corpuscles may also be seen here and there in the areolar tissues (wander- 

 cells). In the middle coat of the eye the connective-tissue cells are filled 

 with granules of pigment (pigment-cells). 



The cells lie in spaces in the ground-substance between the bundles 

 of white fibres. In some parts of the connective tissue the white 

 bundles are developed to such an extent as to pervade almost the 

 whole of the ground-substance, and then the connective-tissue corpuscles 

 become squeezed into the interstices, flattened lamellar expansions of 

 the cells extending between the bundles, as in tendon (see next Lesson). 



The cells and cell-spaces of areolar tissue come into intimate relation 

 with the cells lining the lymphatic vessels and small blood-vessels. 

 This connection can best be seen in silvered preparations ; it will be 

 again referred to in speaking of the origin of the lymphatics. 



FlG. 43. A SMALL FAT-LOBULE FROM THE SUBCUTANEOUS TISSUE OF THE 

 GUINEA-PIG, (%-. ) 



a, small artery distributed to the lobule ; 6, small vein ; the capillaries within the lobule 



are not visible. 



Adipose tissue consists of vesicles filled with fat (figs. 43, 44), and 

 collected into lobules, or into tracts which accompany the small blood- 

 vessels. The vesicles are round or oval in shape, except where closely 

 packed, when they become polyhedral from mutual compression. The 

 fat-drop is contained within a delicate protoplasmic envelope (fig. 44, 

 m) which is thickened at one part, and here includes an oval flattened 

 nucleus. The vesicles are supported partly by filaments of areolar 

 tissue, but chiefly by a fine network of capillary blood-vessels. 



