INVOLUNTARY MUSCULAR FIBRE. 



129 



or three days in glycerine, the lining epithelium is easily 

 brushed off. The bladder of the frog is peculiarly favorable, 

 because it affords an opportunity of studying the fibres, both 



Fio. 50. 



Fia. 51. 



Fio. 62. 



Fio. 50. Muscular fibres treated with serum. FIG. 51. Muscular fibres from the muscular tissue 

 of the intestine, isolated by means of nitric acid. FIG. 52. Muscular fibres from a pleuritic membrane. 

 J. Arnold. 



separately and in bundles, in its walls and in the coats of the 

 minute arterioles which nourish it. 



The plain fibre is composed simply of one or more elongated 



