ELEMENTARY PHYSIOLOGY 



composed of bundles of fibres, but that each bundle is made up of 

 still smaller bundles, each of which is distinctly visible to the 



naked eye. These smaller bundles 

 are called fasciculi (Lat. fasciculus, 

 a little bundle) ; and the fineness 

 or coarseness of a muscle depends 

 on the relative sizes of these small 

 bundles of fibres. Thus, in the 

 powerful muscles of the leg, the 

 fasciculi are much larger than in the 

 softer muscles of the cheeks. 



If it is desired to study the structure 

 more minutely, it will be necessary to take 



Fig. 56. A few Muscular Fibres, 

 being part of a smaller Fasci- 

 culus, more highly magnified. 



a, end view of fibres ; b, side view of fibres ; 

 c. a fibre split into fibrils. 



Fig- 57- A. muscular Fibre rup- 

 tured, so as to exhibit the 

 Sarcolemma. 



Fig. 58. Involuntary Mus- 

 cular Fibre-cells from Human 

 Blood-vessels. 



Magnified 350 diameters 



Fig. 59. Muscular Fibres from 

 the Heart, showing the 

 Striations and the Junctions 

 of the Cells. 



Highly magnified. 



