MICKOSCOl^IC STEUCTUEE OF STEIATED MUSCLE 273 



colemma and scattered over the body of the fiber are sev- 

 eral oval bodies which indicate the true nature of the 

 fiber. These oval bodies are nuclei and the fiber is actu- 



FiG. 118 — A, muscle fiber with sarcolemma removed and broken at one end into 

 itsfibrillse ;B, separate tibrill^ ; C, muscle fiber breaking into disks ; D, muscular 

 fiber, tbe contractile substance of which (a) is torn, while the sarcolemraa (b) has 

 not given way (X 350). 



ally a composite muscle cell. Such a cell is called a multi- 

 nuclear cell and the sarcolemma is the common cell wall. 

 Viewed as a multinuclear cell the above structures bear 

 the following relations to the cell as we know it. The 

 sarcolemma is the common cell wall. The contractile 

 substance is protoplasm in which the power of contraction 

 and expansion has become greatly developed. Such 

 specialized protoplasm is called sarcoplasm, or muscle- 



EDDY. PHYS. 



