YELLOW FIBROUS TISSUE. 



269 



being marked with transverse striae, not extending quite across 

 them, but being principally confined to the centre of each. Kolli- 

 ker asserts that this appearance is due to the formation of little 

 cavities within the fibres. (Fig. 170, B.) 



A. Yellow elastic fibres from the ligamentum nuchse of a sheep. B. Yellow fibres from the liga- 

 mentum nuchse of the giraffe, c. One of the same, magnified 500 diameters. D. Vessels of the liga- 

 mentum nuchse of a young calf. (Queckett.) 



3. The third variety consists of flat, rather broad, somewhat 

 brittle, and much ramifying bands (Fig. 171), often so arranged as 

 to form a network (or in the form of the finest, straight threads 

 (Fig. 172), as in the peritoneum of some young animals), as found 

 in the middle coat of arteries. The elastic fibres studded with 

 nuclei have been called nuclear fibres. But all may have been so at 

 first; at least the largest were originally as small as those. (Fig. 173). 



Elastic fibres cannot be isolated for examination by mere mecha- 

 nical means, since they never occur independently of other histo- 

 logical elements. They always appear where the white fibrous 

 tissue exists, and are often blended, as in the middle coat of arteries, 

 with the smooth muscular fibres. The last two elements may, how- 

 ever, be removed by boiling with acetic acid, and then adding a 

 dilute solution of potash, when the isolated elastic fibres remain. 



