POISON OF SOME INDIAN VENOMOUS SNAKES. 59 



The action of the poison on motor nerves is illustrated by the 

 following experiments, performed by Bernard's method of 

 ligaturing one leg of a frog before poisorring it. The poison is 

 thus carried to every part of the body except the ligatured 

 limb, the motions of which indicate the state of the nerve- 

 centres after the other parts of the body have been paralysed. 



Experiment XXXVI. 



A ligature was placed round the right thigh of a young frog, 

 excluding the sciatic nerve. 



2.42. A drop of dark fluid cobra-poison (the first supply) was 

 injected into the dorsal lymph-sac. Immediately after the 

 injection the animal became restless. 



3.0. It lies quietly with its eyes shut. It hardly moves when 

 touched ; but it struggles when laid upon its back. 



3*8. It can still drav^ up the ligatured leg. The other one 

 can be drawn up, but with a wriggling motion. When laid on 

 its back the animal no longer resists. 



3.9.30. It lies quite flat. There is trembling of the leg when 

 either foot is touched ; and when it is pinched, either leg can 

 still be drawn up. On suddenly touching the poisoned leg, the 

 frog gave a jerk with both. Kespiratory movements have 

 ceased. The exact time when they did so was not noticed. 



3.17. The frog has become much lighter in colour, with the 

 exception of the ligatured leg. 



3.45. The eyes no longer shut when touched ; they remain 

 widely open. Dilute acetic acid of 1 per cent, produces no 

 effect when applied to the sound leg ; but when the leg is lifted 

 up, so as to prevent friction against the table, it is drawn in 

 towards the body. 



4.9. On applying a strong interrupted current to the eye of 

 the frog the unpoisoned leg jerks feebly, the poisoned one not 

 at all. 



4.13. On turning the frog on his back the non-poisoned leg 

 moved. 



4.20. Opened abdomen. The heart was beating, but only 

 slowly. Irritated the lumbar nerves on the left side (those of 

 poisoned leg) by an interrupted current. ISTo contraction 



