1874.] Poison of Indian Venomous Snakes. 101 



May 2 Is*. The sciatics of the other legs were exposed and irritated. 



Distance of primary from secondary coil. 

 Time. Frog 1. JBYog 2. 



11-5 Frog 1, no contraction. Erog 2, 



slight contraction. The irri- 

 tability of the muscles was 

 now tested by single induced 

 shocks applied to them. 



7'5 Erog 1, no contraction. Frog 2, 



slight contraction. 



The disturbing effects occasioned in the other experiments by the 

 necessity of comparing a limb acted on by the poison, but retaining its 

 blood-supply, with one in which the circulation had been arrested, is here 

 got rid of by employing two frogs of as nearly as possible the same size. 

 The paralysis of nerves caused by the poison is evident. 



Experiment XL-Ill. 



Dec. 4th. Bight leg ligatured, with the exception of the sciatic nerve ; 

 a small quantity of alcoholic extract of cobra-poison dissolved in water 

 injected into the dorsal lymph-sac. 



Noon. Injection made. 



1.30. The frog lies quite helpless. A spark of electricity applied to 

 the side causes reflex contraction of both legs. When the poisoned leg is 

 drawn out, the frog draws it up again with a wriggling motion. The 

 poisoned leg at once reacts when the toes are pinched ; the ligatured 

 one does not. 



When the sides of the frog are irritated by an electric spark, all the 

 legs, except the ligatured one, give a twitch. 



3.50. On exposing the lumbar nerves in the abdominal cavity and irri- 

 tating them by an induced current, the poisoned leg contracted, the liga- 

 tured one did not. 



The effect of the alcoholic extract in causing paralysis is shown by this 

 experiment ; but the insensibility of the ligatured leg, which was in all 

 probability due to an injury of the sciatic nerve by the ligature, renders* 

 it difficult to say how much of the paralysis was due to the cord, and how 

 much to the nerves. That the nerves were affected, however, seems clear 

 from the fact that the muscles no longer reacted to voluntary stimuli, 

 but did so when an extraordinary stimulus was occasioned by pinching. 



Experiment XLIV. 



Aug. 27th. A small dog was chloroformed, and both vagi were ex- 

 posed. 



12.35 P.M. About two grains of dried cobra-poison were injected into 

 the peritoneal cavity. 



12.42. Water was thrown over the animal to revive him more com- 



i 2 



