ANIMAL PHYSIOLOGY. 



mals the muscles of the tympanum, which are stimulated 

 precisely in the same way as the iris, are of the striped 

 description. 



a, ' ~b ' 



Pig. 30. STRIPED MUSCULAR FIBRE, a, undisturbed fibre ; 

 treated with acetic acid, to show the nuclei ; c, the striated 

 substance torn and the sarcolemma uninjured; d, fibre teased 

 out to show the fibrillse ; c, fibre broken into discs above, a*nd 

 showing fibrillse below ; /, termination of nerve, after Kiihne. 



30. Striped Muscular Tissue consists of very long fibres 

 which, in their best developed varieties, approach -$ 

 of an inch in diameter. In most instances each fibre 

 exhibits a delicate sheath or sarcolemma, which, in its 

 resistance of reagents, resembles elastic tissue. The sar- 

 colemma is filled with substance which is closely striped 

 or striated transversely, the striation depending on a 

 regular alternation of parts of different refractive pro- 

 perties. By careful manipulation this striated substance 

 may be separated up into a bundle of fine threads called 

 jfibrillce, each of which exhibits the same alternation of parts 

 which causes the striation of the fibre, and may be looked on 

 as a series of dark or highly refractive parts, the sarcous 

 elements of Bowman, connected by means of a less dense 

 material. By other modes of manipulation the striped fibres 

 may be partially cleft across, so as to present the appearance 

 of a series of discs ; and there is no sufficient reason for sup- 

 posing that the division into fibrillse is more natural than 

 this division into discs. To the interior of the sarcolemma 

 are adherent a number of elongated nuclei ; and it is inipor- 



