KUHNE'S EXPERIMENT. 197 



(6.) Pith a frog, expose the sciatic nerve down to the 

 knee (Fig. 87, S). Trace the two branches into which it 

 divides. Divide one of the branches as near as possible to 

 the knee, and stimulate its central end (P). The muscles 

 supplied by the other division of the nerve (T) contract. 



6. Ktihne's Experiment. 



(a.) Invert an ordinary earthenware bowl (B), and fix 

 with wax to its base a piece of glass 10 cm. square (Fig. 

 88, G). 



Fig. 88. Kiihne's Experiment. B, Bowl ; G, glass plate ; 

 N, nerve on P, P', pads of clay ; C, capsule. 



(6.) Roll two plugs of kaolin (moistened with normal 

 saline), about 1 cm. in diameter and 6 cm. in length (P, P'), 

 bend them at a right angle, and hang them over the glass 

 plate about 6 mm. apart. 



(c.) Make a nerve-muscle preparation, lay the muscle on 

 the glass plate, and the nerve over the two rolls of china 

 clay (Fig. 88, N). 



(d.) Fill a small glass vessel (0) with normal saline, and 

 allow the two free ends of the clay to dip into it. With 

 each dip the muscle contracts. In this case the nerve is 

 stimulated by the completion of the circuit of its own 

 demarcation current. 



