en. 



AREOLAR TISSUE 



29 



Areolar Tissue. 



This is a very typical connective tissue. It has a wide distribu- 

 tion, and constitutes the subcutaneous, subserous, and submucous 

 tissues. It forms sheaths (fasciae) for muscles, nerves, blood-vessels, 

 glands, and internal organs, binding them in position and penetrat- 

 ing into their interior, supports and connects their individual parts. 



Fio. 38. Loose areolar tissue from the subcutaneous tissue of the cat. x 300. Tliis shows the two 

 varieties of iibres, and two of the varieties of connective-tissue"corpuscles, namely, the lamellar 

 cells or fibroblasts, and a wander cell. 1, Lamellar cell; 2, wander cell; 3, elastic fibres; 4, 

 bundles of white fibres. (After Szymonowicz.) 



On microscopic examination it is soon that this typical connective 

 tissue consists of four different kinds of material, or, as they may be 

 termed, histological elements. They are : 



(a) Cells, or connective-tissue corpuscles. 



(b) A homogeneous matrix, ground substance, or intercellular 



material. 



(c) White fibres ) r ., , . ,, 



(d) Yellow or elastic fibres } These are de P oslted m fche matnx ' 



In considering these four histological elements we may first take 

 the fibres, because they are the most obvious and abundant of the 

 structures observable. 



The white fibres. These are exquisitely fine fibres collected into 

 bundles which have a wavy outline. The bundles run in different 

 directions, forming an irregular network, the meshes between which 

 are called areolce ; hence the name areolar. 



They are composed of the chemical substance called collagen. On 

 boiling they yield gelatin; some chemists regard collagen as the 

 anhydride of gelatin ; but whether this is so or not, the gelatin is 

 undoubtedly derived from the collagen. Gelatin is a protein though 



