XIII.J THE FROG. 247 



b. Examine with, high power. 



a. The alternate lighter and darker bands placed 

 transversely to the long axis of the fibre 

 {transverse striation). 



/S. The fine structureless membrane (sarcolemma) 

 enveloping the fibre : seen here and there as 

 a delicate film where the fibre is twisted or 

 bruised. 



7. The tendency to split up into fibrillae. 



c. Tease out a bit of fresh muscle in 075^ sodic 

 chloride solution. 



a. The transverse striation of the fibres : less dis- 

 tinct than in the muscle from alcohol. 



/3. The absence of a tendency to split up into 

 fibrillae. 



7. The sarcolemma, which may be seen at points 

 where the continuity of its contents has been 

 interrupted by pressure, twisting, &c. 



S. Treat with acetic acid : the striation rendered 

 very indistinct; oval nuclei made apparent 

 here and there in the fibre. 



f. Nerve-fibres. 



1. Tease out a bit of fresh nerve in 0-7o§ sodic 

 chloride. Examine with a high power. 



a. Composed of well-defined fibres {white nerve- 

 fibres) mixed with white fibrous tissue (d. 1. a). 



h. The appearance of the nerve-fibres: each has 

 a double contour, marked out by a curdled- 

 looking highly refractive border on each side. 



