MUSCLES. 49 



i 



Striped Muscle. The tissue of muscle in its sim- 

 plest element the primitive fibre is variable in its 

 physiognomy, presenting to the eye but two con- 

 stant features, viz : an external envelope, with con- 

 tents marked by transverse stripes. (PL IX. fig. V. 

 and PL X.) 



The primitive fibre is usually polygonal, rarely striped fibre. 

 cylindrical ; its envelope, called myolemina or sarco- 

 lemma,* is readily recognisable, either without any 

 previous preparation, or by the aid of chemical re- 

 agents, as a perfectly structureless membrane. Nei- 

 ther in the living nor dead fibre, neither in the state 

 of contraction nor of relaxation, can any folds or 

 wrinkles be detected in it corresponding with the 

 cross stripings of its contents. On its internal sur- 

 face, at regular intervals, oval nuclei (PL X. fig. II. 3 ; 

 PL IX. fig. V. 3) are visible the last traces of the 

 cellular origin of muscle. It is exceedingly elastic. 



On examining its contents, the most marked fea- 

 tures observed are the transverse stripes, equidistant 

 from and parallel with each other. Occasionally 

 longitudinal striae are to be detected in muscular fibre 

 instead of the transverse stripes, and in rare instances 

 both the longitudinal and transverse stripes are pre- 

 sent. (PL X. fig. II. 4, 5.) If this contained sub- 

 stance is still farther analysed by the aid of chemical 

 re-agents (chromic acid, alcohol, etc.) or prepared by 

 boiling, and even sometimes without the employment 



* This term was introduced by Bowman, who first investigated and , . 

 described the sarcolemma, and its relation to the primitive muscular fibre 

 of the striated variety. V. Cyclop, of Anat. and Physiology, Art. Muscle, 

 and Todd and Bowman's Phyt* Anat. (Ed.} 



