584 



MOTION. 



To this kind of muscular fibre the term organic is often 

 Fi but loosely applied, from 



the fact that it enters 

 especially into the con- 

 struction of such parts 

 as are concerned in 

 what has been called 

 organic life (see note, 

 p. 466). 



The muscles of animal 

 life, or striped muscles, 

 include the whole class 

 of voluntary muscles, the heart, and those muscles neither 

 completely voluntary nor involuntary, which form part of 

 the walls of the pharynx, and exist in many other parts of 



Fig. I5i.t 



\ 



the body, as the internal 

 ear, urethra, etc. All 

 these muscles are com- 

 posed of fleshy bundles 

 called fasciculi, enclosed 

 in coverings of fibro- 

 cellular tissue, by which 

 each is at once connect- 

 ed with, and isolated 

 from, those adjacent to 



it (fig. 151). Each bundle is again divided into smaller 

 ones, similarly ensheathed and similarly divisible ; and so 

 on, through an uncertain number of gradations, till, just 

 beyond the reach of the unaided eye, one arrives at the jn- 

 mitive fasciculi, or the muscular fibres peculiarly so called. 



* Fig. 150. Perpendicular section through the scalp, with two hair- 

 sacs ; , epidermis ; b, cutis ; c, muscles of the hair-follicles (after 

 KoUiker). 



t Fig. 151. A small portion of muscle, natural size, consisting of 

 larger and smaller fasciculi, seen in a transverse section, and the same 

 magnified 5 diameters (after Sharpey), 



