114 GENERAL PROPERTIES OF LIVING TISSUES 



bility of the particular nerve in hand. We will 

 test first the effect of the ascending current. 



Connect a dry cell through an open key with 

 the metre posts of the rheochord (Fig. 30). Join 

 the positive post and the slider through a pole- 

 changer (cross-wires in place), with the non- 

 polarizable electrodes placed in the moist 



Pig. 30. 



chamber (Fig. 24, page 95), in the holders farthest 

 from the opening for the muscle. Make a 

 nerve-muscle preparation. Secure the femur in 

 the femur clamp of the moist chamber. Let 

 the nerve lie on the non-polarizable electrodes. 

 Attach the Achilles tendon to the muscle lever. 

 Keep the air in the chamber moist by lining 

 the glass shade with filter paper saturated with 

 water. Arrange the pole-changer so that the 



1 The inductorium shown in Fig. 30 is not used in this ex- 

 periment, but in the first experiment on page 116. 



