60 ON THE NATURE AND ACTION OF THE 



occurred in the poisoned leg ; but twitching took place in the 

 non-poisoned one. Irritated lumbar nerves of right side. 

 Tetanus occurred in the right (non-poisoned leg). No move- 

 ment of the poisoned leg. Laid bare the muscles of both legs, 

 and irritated them by a Faradic current directly applied. 

 Those of the poisoned leg were paler than those of the other. 

 The muscles of both legs contracted when irritated directly. 

 Exposed the sciatic nerves of both sides and_irritated them by 

 an induced current. No contraction in the gastrocnemius of 

 poisoned leg. Tetanus in the non-poisoned leg. 



4.35. The heart is no longer contracting. Electrodes were 

 placed in the medulla, and an interrupted current applied. 

 Contractions occurred in the non-poisoned leg. No contractions 

 in the poisoned one. 



The movements which occurred in the non-poisoned leg when 

 the lumbar nerves of the other side were irritated may have 

 been due to reflex action through the spinal cord. If this were 

 the case, it would indicate that the sensory fibres in the lumbar 

 plexus were not paralysed, and that the reflex power of the 

 cord was not quite destroyed ; but the nerves were not very 

 carefully isolated, and it is probable that the twitchings were 

 due to direct irritation of the lumbar nerves of the right side 

 by conducted currents, especially as irritation of the left sciatic 

 nerve caused no movement in the right foot. 



The continuance of movement in the ligatured leg, after it 

 had ceased in other parts of the body, indicates that the ends of 

 the motor nerves have been paralysed ; and this is confirmed 

 by the production of tetanus in the ligatured and absence of 

 movement in the poisoned leg when their motor nerves are 

 stimulated. The slightness of the movements in the ligatured 

 leg when a strong interrupted current was applied to the eye, 

 while the motor nerves of the limb still retained their irrita- 

 bility, indicates that paralysis of the reflex function of the cord 

 had taken place. The motion of the leg on turning the frog on 

 his back afterwards shows that the higher nervous centres, 

 through which the opposition to the change of posture was 

 manifested, retained their power longer than the cord. 



