62 ON THE NATURE AND ACTION OF THE 



Experiment XXXVIII. 



May 14tli. — The right leg of a frog was ligatured, with the 

 exception of the sciatic nerve, and the animal poisoned by a 

 rather small dose of dried cobra-poison dissolved in water, and 

 injected into tlie dorsal lymph-sac at 11.45 a.m. 



12.15. The animal paralysed. Acetic acid applied to the left 

 arm caused movements in it ; but no movements ensued when 

 the acid was applied to the nose. When applied to both arms 

 and one leg, it caused movements in the arms and the left leg, 

 but none in the right leg. 



12.33. Acetic acid applied to the left arm causes movement 

 in it, but in no other part of the body. 



12.51. Electrodes were placed in the spine and the cord 

 irritated by a Faradic current. At 15 cm. distance of the 

 secondary from the primary coil there is faint twitch in right 

 arm. At 9, distinct twitch in both arms. At 0, distinct twitch 

 in both arms, none in legs ; sciatics exposed and irritated. 

 At 50, right leg contracts distinctly. At 36, right leg becomes 

 tetanised. At 16, left leg contracts very faintly indeed. At 8 

 left leg contracts slightly. 



The muscles were then irritated by single induced shocks : — 

 9"8 cm., right leg faint contraction; 9"8, left (poisoned) leg 

 contraction is equally strong; lO'l, left (poisoned) leg contrac- 

 tion occurs. 10"1, right (ligatured one) does not contract. 



In this experiment, the irritability of the poisoned muscle is 

 greater than that of the other, the venom having done less 

 injmy to the muscular substance than the deprivation of blood 

 by the ligature, and consequently the paralysing action of the 

 poison on the ends of the motor nerves becomes very evident. 



Experiment XXXIX. 



May 12th, 1873. — A ligature was passed tightly round the 

 right thigh of a large frog, the sciatic nerve being excluded. 



12. Eight leg ligatured. 



12.12. Injected a considerable dose of a solution of dried 

 •cobra-poison in wn^^er into dorsal lymph-sac. 



12.14. The frog has assumed a most peculiar position. The 



