CONNECTIVE TISSUE. 37 



The second variety of fibres which occurs in con- 

 nective tissue the elastic fibres are much more 

 strongly refractive than the first, hence presenting 

 more sharply marked contours ; they are not longi- 

 T tudinally striated, and often branch and form anas- 

 tomoses with one another, sometimes joining at 

 frequent intervals to form a narrow-meshed net, and 

 again stretching away for long distances to form a 

 broadly spaced reticulum. Sometimes the fibres 

 are broad and band-like, sometimes extremely fine ; 

 on being boiled in water they are not converted 

 into gelatin, and they are unchanged by acetic acid 

 and dilute alkalies. These fibres, as their name in- 

 dicates, possess elasticity, and as a consequence of 

 this property we often find, when the fibres have 

 been severed by teasing or other modes of prepara- 

 tion, that the free ends curl over in the act of re- 

 traction, forming very characteristic curves or 

 spirals. The elastic substance sometimes occurs in 

 the form of granules instead of fibres, or as nearly 

 homogeneous membranes. 



The relative number of the fibrillar and elastic 

 fibres in connective tissue varies greatly in different 

 parts of the body ; in some we find but few elastic 

 fibres, others contain little else. The insterstices of 

 the interlacing fibres both fibrillated and elastic 

 are filled with the nutritive fluids of the body ; or 

 in some cases, a small amount of a more consistent 

 homogeneous material cements them together. 



