CHAPTER V. 



THE CONNECTIVE SUBSTANCE GKOUP. 



MUCOUS OR GELATINOUS TISSUE ; ADENOID TISSUE ; NEUROG- 

 LIA ; FAT TISSUE ; FIBROUS TISSUE PROPER ; CORNEAL TIS- 

 SUE ; INTERMUSCULAR TISSUE ; TENDON TISSUE ; ELASTIC 

 TISSUE. 



THE term connective substance was first proposed by Reich- 

 ert in 1845, and is now applied to a class of animal tissues whose 

 offices are very important in the economy. Prominent among 

 them is bone, which forms the solid framework of the body, 

 gives it strength, and supplies points of attachment for muscles 

 and tendons ; another group comprises the ligaments, which 

 assist in holding the bony parts, and also some organs, in their 

 proper relations ; others again, of a more delicate nature, fur- 

 nish support or protection for epithelial bodies, blood-vessels, 

 and nerves. Just at the present time the histology of connec- 

 tive substances has an important bearing on many points that 

 relate to inflammation, degeneration, and the development of 

 certain new growths, and it is therefore desirable to have a clear 

 conception of them. This object is best effected by studying 

 each variety separately, not only in its normal condition, but 

 under the changes it exhibits when acted on by the factors that 

 are concerned in the processes of disease. 



It is a property of these substances that they supplant one 

 another at different times or under peculiar circumstances. As 

 an example, the hyaline cartilage of young life may change 

 into true bone in old age, while, on the other hand, there is 

 always a tendency for fully formed tissue, if inflamed, to re- 

 vert toward the embryonic type. 



The connective substances may be subdivided as follows : 

 1, mucous or gelatinous tissue ; 2, adenoid tissue ; 3, neurog- 



