POISON OF SOME INDIAN VE.\OMOUS SNAKES. 65 



Applied to right forearm it caused a weak kick in right hind 

 leg and wriggling in left hind leg, but no motion in any other 

 part. 



12.27. Acetic acid applied to forearm. Ko reflex action 

 anywhere. 



12.30. No reflex action anywhere on application of acetic acid. 



12.30. Distance of coil 8. Electrodes in the spinal cord. 

 Slight contractions in right hind and left fore legs, and also in 

 the abdominal muscles, though very weak. It was now 

 noticed that the cord with which the frog was attached to the 

 board had been very tightly tied round the left forearm and 

 left there. The circulation was stopped there, as the cord had 

 not been removed. 



The paralysing effect of the poison on the motor nerves was 

 here shown by an involuntary experiment. On irritating the 

 cord the ligatured leg responded as we had expected, but we 

 were astonished to see movements in the left arm also. An 

 examination of the limb at once showed the cause of the 

 phenomenon. The cord attaching it to the board had been 

 inadvertently drawn so tight as to obstruct the circulation, and 

 thus prevented the access of the poison to the nerves. 



Experiment XLI. 



May 15th. — Right thigh of frog ligatured, with exception of 

 the sciatic nerve. 



1.2. Ligature applied. 



1.4. A considerable dose of dried cobra-poison dissolved in 

 water injected into dorsal lymph-sac. 



2.26. Acetic acid applied to a limb causes no movement 

 whatever in 60 ^ 



Interrupted current. Distance 0, electrodes in spine ; only 

 weak twitch in muscles of forearms ; no movement in hind leg. 



2.30. Both sciatics exposed. 



Right sciatic. Distance 50, distinct contraction of gastro- 

 cnemius. 



Left sciatic. Distance 0, no contraction of gastrocnemius. 

 Single shocks. Both gastrocnemii exposed and irritated 

 directly. 



(,95) F 



