26 PRACTICAL PHYSIOLOGY 



connected with the nerve, the battery being cut off 

 by the same movement. 



5. That the nerve can be stimulated by mechan- 

 ical means e.g., by tapping it gently or by allowing 

 mercury to drop upon it from a height of three or 

 four inches. The effect of a mechanical stimulus is 

 also seen whenever a nerve is cut or pinched, but 

 such severe injury abolishes its conducting func- 

 tions. 



6. That the nerve is stimulated if it be touched 

 with a hot wire. 



7. That it can be stimulated by chemical means, 

 as by placing wet salt or strong glycerine upon a 

 freshly cut end. 



8. That drying acts as a stimulus to the nerve. 

 If it be raised off the wet blotting paper and begin 

 to dry, the muscle will be observed to begin to 

 twitch. The salt and glycerine in the last experi- 

 ment probably also act by abstracting water. 



Preparation of the sartorius muscle. The 

 thin, flat sartorius is seen crossing obliquely over 

 the front of the thigh. It is readily isolated by 

 tying a thread round its tendinous attachment to 

 the tibia, cutting this attachment away from the 

 bone, raising the lower end by the aid of the thread, 

 and snipping through the fascia on either side of the 

 muscle, thus separating it right up to its iliac attach- 

 ment. Notice the twitch which occurs when the, 

 nerve, which enters the under surface about its 

 middle, is cut through. The muscle may be left 

 attached to the ilium, or its bony attachment may be 

 cut away with it and the muscle thus completely 



