THE RABBIT. 



51 



Fig. 14. AREOLAR TISSUE. 



All epithelial tissues are characterized by the fact that 

 no blood-capillaries occur in them. This might be expected 

 in tissues composed only of cells. But as the blocd must be 

 brought near to these 

 epithelia we always 

 find at the base of an 

 epithelium a layer of 



a 



connective tissue con- 

 taining abundant 

 blood - capillaries. In 

 the case of the skin, 

 this layer is the dermis : 

 epidermis and derrnis 

 together constitute the 

 skin. 



7. Connective 

 Tissues. In the con- 

 nective tissues, we find that both cells and cell-products are 

 present, the latter often forming the great bulk of the 

 tissue. Most usually the cell-products are ectoplastic. In 

 this case it is customary to call the cells by the old name of 

 corpuscles, and the cell-products, the matrix. 



Areolar tissue (or ordinary connective tissue) consists of 

 cells (connective tissue-corpuscles), usually of irregular 

 shape,* and running out into fine threads, separated from 

 one another by a soft, jelly-like matrix, consisting mainly of 

 the substance gelatin (a compound allied to the proteids). 

 Running through this matrix are a quantity of fine fibres, 

 formerly thought to be altered cells, but now known to be 

 formed along with the matrix. These fibres are of two 

 kinds yellow fibres which branch and are highly elastic, 

 and white fibres which occur in bundles, do not branch, and 

 are inelastic. The presence of these fibres adds strength 

 and elasticity to the delicate matrix. Areolar tissue such as 

 we have described is found surrounding and holding to- 

 gether most of the organs in the body : the process of 



* Hence often said to be " amoeboid " ; but that term is more 

 properly used to indicate that a cell moves like an amoeba, which is 

 not the case here. 



