24 



ELEMENTARY PHYSIOLOGY. III. 



glazed plate, place a piece of blotting paper soaked in 

 Ringer's fluid (cp. p. 16, footnote), on this place the 

 frog on its belly. Prepare (as in Less. II, 1) the nerves 

 giving origin to the sciatic nerve, remove the ileo-fibu- 

 laris muscle (Less. I, 5). 



Fig. 10. Lucas muscle chamber. 



Holding the nerve up by the thread, isolate it as far 

 as the knee by cutting the tissue around it and the 

 branches of the nerve. The nerve must not be pinched 

 or stretched. Tear now the skin from the lower leg. Tie 

 a thread round the tendo Achillis of the gastrocnemius 

 muscle, and tie the two ends to make a loop about half 

 an inch from the tendon. Cut the tendon below the 

 ligature and pulling on this isolate the muscle up to the 



