CONNECTIVE TISSUE. 185 



In the umbilical cord, a large number of plastids coalesce 

 into territories of a partly myxomatous, partly fibrous, basis- 

 substance, and these territories are separated by a broad reticu- 

 lum of plastids, the " stellate mucoid-cells " ; 



In fibrous connective tissue, each bundle is the result of 

 coalescence of plastids much elongated and split up, and is 

 composed of one or a number of territories, in which remain the 

 connective-tissue corpuscles. A large number of plastids is left 

 between the bundles $ 



In tendon, each bundle is a large territory containing a 

 number of plastids arranged in chains, with numerous smaller 

 bundles between them ; 



In periosteum, the plastids have flattened out so as to build up 

 a rhomboidal ribbon, with a number of unchanged plastids, each 

 ribbon being composed of one territory or of a number of them ; 



In the cornea, the flattened bundles or ribbons have coalesced 

 into layers, traversed by the cornea corpuscles ; each lamella is a 

 flattened territory, and between the territories are plastids similar 

 to those within. 



Between the groups, composed of plastids in many instances, 

 and at an early stage of development, a very dense basis- or cement- 

 substance appears. This is the " elastic tissue," seen in the 

 periosteum in the shape of narrow plates or strips at the borders 

 of the ribbons and their constituent fields. In the finished tissue, 

 the elastic strips in varying amount border one or several terri- 

 tories, sometimes even smaller fields in one territory. The glue- 

 yielding basis-substance, formed later, is by no means as dense 

 and resistant as the first-formed elastic substance. This is proved 

 by observations in inflamed periosteum. The basis-substance, 

 however, is densified and made resistant, not only at the borders 

 of the territories, but also around the cavities containing the 

 plastids. This is the case in fibrous connective tissue as well as 

 in cartilage- and bone-tissue. 



The so-catted " elastic tissue " is evidently no tissue sui generis, 

 but a basis- or cement-substance, of an early formation and of con- 

 siderable density. It arises from plastids, just as the glue-yielding 

 basis-substance proper. 



(3) CARTILAGE TISSUE. 



History.* From the earliest time of histology to the present, true cartilage, 

 such as the thyroid cartilage, has been looked upon as one of the simplest 



* Written by Louis Elsberg : "Contributions to the Normal and Pathological Histology 

 of the Cartilages of the Larynx," Archives of Laryngology, vol. ii., 1881. 



