THE CONNECTIVE TISSUES. 



99 



cally, in fig. 61, combined from a number of figures illustrating F. P. 

 Mall's article dealing with this subject. 



The fibers of white fibrous tissue develop in the exoplasm, while 

 the endoplasm containing the nuclei rests on the bundles. In cartil- 

 age the ground-substance or matrix is deposited into the exoplasm 

 of the syncytium, the endoplasm and nuclei forming the cartilage 

 cells. In bone, the bone substance or matrix is developed from the 

 exoplasm, either by a transformation of it or by a deposition in it, 

 while the endoplasm increases and the nuclei enlarge to form the 

 bone-forming cells, the osteoblasts. The reticulum of reticular con- 

 nective tissue is developed directly from the exoplasm of the syncy- 

 tium, while the nuclei and endoplasm are converted into cells which 

 rest upon the reticulum fibrils. 



The following kinds of connective tissue are recognized: (i) 

 mucous connective tissue, (2) reticular connective tissue, (3) fibrous 

 connective tissue, (4) adipose tissue, (5) cartilage, (6) bone. 



Fig. 62. White fibrils and small bun- 

 dles of white fibrils from teased preparation 

 of a fresh tendon from the tail of a rat. 



Fig. 62^. Elastic fibers from the liga- 

 mentum nuchae of the ox, teased fresh ; 

 X SOD. At a the fiber is curved in a char- 

 acteristic manner. 



The fibrous connective tissues are composed of a ground-sub- 

 stance or matrix in which are imbedded the cellular elements and 

 two kinds of connective-tissue fibers, namely, white and elastic 

 fibers. As the character of the fibrous connective tissue depends 

 largely on the arrangement of the fibers and on the relative propor- 

 tion of the white and elastic fibers, these will be considered prior to 

 a description of the several types of fibrous connective tissue. 



White Fibers. White fibrous connective tissue consists of ex- 

 ceedingly fine homogeneous fibrillae, cemented by a small amount 

 of an interfibrillar cement substance into bundles vaiying in size. In 

 the bundles these fibrillae have a parallel course, although the bun- 

 dles are often slightly wavy. The fibrillae of white fibrous connective 

 tissue vary in size from 0.25 to I //, and neither branch nor anasto- 

 mose. They become transparent and swollen when treated with 

 acetic acid, are not at all or only very slowly digested by pancreatin, 

 and yield gelatin on boiling. 



