LESSON XVI. 



ENDINGS OF NERVE FIBRES IN MUSCLE. 



1. The End-Brush. Take a pithed frog, and 

 expose the sartorius muscle (cp. Less. xm. 1). Free 

 this at its lower end ; raise it by the short tendon and 

 cut through the connective tissue on either side and 

 below it, close to the muscle, being careful not to 

 injure the muscle fibres. Cut through the upper 

 attachment. Place the muscle on a slide, deep side 

 uppermost, add two drops of '05 p.c. methylene blue 

 dissolved in '6 p.c. NaCl. Line a watch-glass with 

 moist blotting-paper, and with it cover the specimen. 

 Leave for 15 to 20 minutes; then drain off the 

 methylene blue. Gently pull the ends with needles 

 to extend the muscle, add one drop of normal salt 

 solution, and examine with low objective and high 

 ocular. 



Follow the muscle fibres along, until the small 

 rather opaque nerve entering the muscle is seen ; trace 

 the course of the nerve across the muscle fibres. Here 

 and there, one or two nerve fibres will be seen leaving 



