( Continued from preceding page. ) 



Fig. S. Longitudinal section of a portion of a muscle fiber from the carotid 

 of ox — just beginning to contract, sliowing both fine and coarse myofibrillnp — 

 g. p., granular protoplasm ; c. mf., coarse myofibrillje ; c. f., collagenous fibers ; 

 e. f., an elastic fiber showing the wavy course due to contraction of adjacent 

 muscle fibers. Zenker's fluid. Iron-htematoxylin. x l"-'<'5. 



Fig. 9. Cross-section of three uncontraeted muscle fibers from just outside 

 the elastica interna of the carotid of ox, showing two types of fibers, one 

 with a large amount of granular protoplasm (g. p.) and only a peripheral 

 layer of myofibrillse, the other with no granular protoplasm and closely packed 

 myofibrillfe — i. s., internodal segment ; c. f., collagenous fibers. Zenker's fluid. 

 Iron-hfematoxylin. x 1375. 



Fig. 10. Section of a portion of a muscle flber from the internal iliac artery 

 of man. showing two nuclei in one mass of granular protoplasm (g. p.).- 

 This fiber has only fine niyofibrilhe (f. nif. ). Formalin. Hensen's htematoxylin. 

 X 1275. 



Fig. 11. Longitudinal section of muscle fibers from the circular layer of 

 the Cfecum of chicken, showing regular contraction waves. The number of 

 contraction nodes in each fiber gives the tissue a cross-striated appearance. 

 The sharp contrast between deeply staining homogeneous contraction node 

 and lightly staining internodal segment is well shown;, (a) shows end to end 

 union of the muscle fibers. The shortening of the nuclei in contraction nodes 

 is indicated — c. n., contraction node ; i. s.. internodal segment ; c. f., col- 

 lagenous fibers. Opposite the contraction nodes the collagenous tissue is 

 condensed. Zenker's fluid. Iron hiematoxylin. x 1275. 



Fi . Cross-section of a portion of the circular coat of the large intes- 



tine ot a dog to show the straight course of the elastic fibers (e. f.) in the 

 imcontracted muscle and the wavy course through the contraction waves. 

 The enlargement of the muscle fibers in the contraction waves is marked. 

 The union of muscle fibers end to end may also be noted — i. s., internodal 

 segment ; c. n., contraction node. Zenker's fiuid, Weigert's resorcin, elastic 

 tissue stain, x 925. 



