Chap. IV] CONNECTIVE TISSUES 39 



uniform, and there are some situations in which it is collected 

 more abundantly. This tissue is found chiefly : — 



(1) Underneath the skin, in the subcutaneous layer. 



(2) Beneath the serous membranes or in their folds. 



(3) Collected in large quantities around certain internal organs, 

 especially the kidneys, which it helps to hold in place. 



(4) Filling up furrows on the surface of the heart. 



(5) As padding around the joints. 



(6) In large quantities in the marrow of the long bones. 

 Function. — Adipose tissue serves several important purposes. 



(1) Unless formed in abnormal quantities it confers graceful out- 

 lines. (2) It constitutes an important reserve fund, which when 

 required can be returned to the blood and oxidized, thus producing 

 heat and energy. (3) It serves as a jacket or covering under the 

 skin, and being a non-conductor of heat, prevents the too rapid 

 loss of heat through the skin. (4) It is an admirable packing 

 material, and serves to fill up spaces in the tissues, and thus af- 

 fords support for delicate structures such as blood-vessels and 

 nerves. 



Reticular or retiform ^ tissue. — This variety of connective tissue 

 consists of a close network of white fibres with few, if any, yellow. 



Fig. 17. — Retiform Tissue from a Lymph Node, r, r, r, represent ope^ 

 meshes of this tissue. (Quaiii.) 



fibres. The meshes of the network are small and close in sOme 

 parts, more open and like areolar tissue in other parts. The fibres 

 are nearly covered by fibrous tissue cells in the form of broad^ thin 



1 Reticulum (from the Latin reticulum "a small net"). Resembling a small 

 net. 



