10 



General Part. 



tissue, cartilage, and bone are recognised. In the first of these 

 the intercellular substance is more or less soft, and the cells 

 are of various shapes, fusiform, stellate, flat. There are three 

 kinds of connective tissue: — cellular, in which the 

 intercellular substance is but slightly developed, often forming 

 ■only a membranous partition between the large vesicular cells : 

 mucous or gelatinous, with a homogeneous and jelly-like 

 intercellular substance (cells rounded or stellate) : and 

 fibrillar connective tissue, where the intercellular substance is 

 composed of delicate threads, among which are often branched 

 elastic fibres ; when these are very numerous, the tissue is called 

 elastic tissue. The intercellular substance of cartilage is firmer, 

 it is usually homogeneous (hyaline cartilage), or it may contain elastic 

 fibres (elastic cartilage) . In this kind of tissue, which is principally 

 found in the Vertebrata, the cells are, as a rule, rounded. Bone is 



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Pig. 10. Hyaline cartilage. — Adapted 

 from Gegenbaur. 



Pig. 11. Bone. ^ After 

 Gegenbaur. 



characterized by a yet greater hardness, on account of the lime salts 



(especially phosphate of lime), which are deposited in the intercellular 



substance.* The cells are stellate, with anastomosing processes. 



This tissue occurs only in the Vertebrata. 



Fat cells are sometimes present in the connective tissue ; 



when they are very abundant, the tissue is termed adipose. The 



cells contain drops of fat or oil, which 

 may increase in number to such an 

 extent that they run together to form 

 one large drop. In this case the cell 

 comes to consist of only a delicate 

 layer of protoplasm surrounding a 

 large drop of oil. Connective tissue 



cells may also contain pigment (usually dark) j these are known 



as pigment cells (chromatophores) . 



Pig. 12. A-B Young fat cells. G 

 Older fat cell, with a, Tery large 

 oil-drop. — Orig. 



* Sometimes lime salts are deposited in oartUage (calcified cartilage). 



