156 ELEMENTARY HISTOLOGY 



i. The bands of muscular fibre, 

 ii. The formation of each band by a number of 



elongated, fusiform, nucleated muscle-cells, 

 iii. The absence of transverse striation in the muscle. 



D. Connective Tissues. 



Under the name " connective tissue " are included various 

 tissues whose functions are mainly passive, and which serve to 

 support, strengthen and bind together the various organs and 

 parts of the body. Histologically the connective tissues consist 

 of elements of four kinds, united together in very varying pro- - 

 portions in different situations: (1) white fibrous tissue; (2) 

 yeUow elastic tissue ; (3) connective tissue corpuscles, which are 

 comparatively slightly altered cells, usually branched ; and (-4) 

 ground substance, or intercellular substance. 



I. White Fibrous Tissue. This consists of a number of fine 



transparent fibres of a more or less cylindrical shape, and 

 with a very characteristic wavy outline ; between the 

 fibres are connective tissue cells, usually in small num- 

 bers. The fibres are arranged side by side in bundles, 

 and each fibre presents a number of longitudinal fibrillar 

 striations. The cellular origin of white fibrous tissue is 

 difficult to determine. The fibres are believed to be 

 formed by modification of the intercellular matrix rather 

 than from the bodies of the cells themselves. 



a. Tendon of rat's tail. PvU out a small piece of tendon 

 from the tail of a rat, ; place it on a slide. in a d/rop of 

 normal salt solution ; spread it out with needles, cover 

 and examine with low and high powers : note : 



i. The fibres, with wavy outlines. 



ii. The fibrillae, indicated by longitudinal wavy stria- 

 tions within the fibres. 



Add a drop of acetic acid to the prepa/ration : oiote that 

 iii. The fibres swell up and become transparent, 

 iv. Longitudinal rows of tendon cells, with nuclei, 

 become visible between the fibres. 



II. Yellow Elastic Tissue. This consists of fine branching 



homogeneous fibres, with great power of resisting 



