126 PRACTICAL HISTOLOGY [XVi 



the nerve, running to the muscle fibres, and ending on 

 them in blue stained nerve-endings. 



Selecting a well stained nerve-ending or end-brush, 

 note that in nearly all cases the branches are given off 

 at right angles to the stem, and that they are not very 

 close together. Fine nerve fibrils accompanying the 

 blood vessels will also be seen. When a number of 

 endings have been examined, put on a cover-slip, gently 

 press. With a low power, put a typical ending in the 

 middle of the field, and then examine it with a high 

 power. 



Soon after the cover-slip is placed on the muscle, 

 the methylene blue begins to be reduced to a colourless 

 compound, and in consequence the nerve fibres become 

 paler till they are no longer seen. 



Note. The success of this preparation depends 

 largely upon not injuring the muscle fibres. Where 

 they are injured, they stain deeply ; they should have 

 no stain at a time when the nerve-endings are deep 

 blue. 



2. Make a similar preparation of the sterno-cutaneous 

 muscle of the frog (Less. xin. 4). The nerve-endings resemble 

 those of the sartorius, but in general are not so large or so 

 regular. 



3. Reflect the skin from the lower jaw. Observe with a 

 dissecting lens the mylohyoid muscle on either side, attached 

 to the edge of the jaw, and, in the middle line, to its fellow 

 muscle. Cut out the conjoined muscle (or cut off the lower jaw, 

 remove everything but the mylohyoids, pin out). Treat as in 1. 

 Note the plexus of fine nerve fibres and fibrils throughout the 

 muscle, and the small and irregular nerve-endings. 



