64 ox THE NATURE AND ACTION OF THE 



Distance of 

 secondary from 

 Leg. primary coil. 



Eight. 37'5 Distinct contraction. 



Left. 7"0 No distinct contraction. When the 



muscles were irritated by single in- 

 duced shocks, applied to them directly, 

 they contracted almost equally. 



Single shock. 7'5 



In this experiment, the right sciatic nerve had been injured 

 by the operation of ligaturing ; and thus the effect of the 

 poison on the other limb as compared with the right one was 

 less manifest. ^N'otwithstanding this it moved, and the other 

 limbs did not, when the right arm was irritated. The difference 

 between the irritability of the sciatic nerves when the muscles 

 of the legs themselves were almost equally irritable, shows, in a 

 marked manner, the influence of the poison on the motor 

 nerves. 



Experiment XL. 



May 14th. — Frog ligatured round the middle, excluding 

 lumbar nerves. 



10.57. Ligature applied. A considerable quantity of blood 

 was lost. 



10.58. A considerable quantity of dried cobra-poison dissolved 

 in water was injected into the dorsal lymph-sac. Immediately 

 after being released the frog jumped about, but became quiet 

 in a minute or so. 



11.28. Made some voluntary movements. 



11.45. Acetic acid to fore feet causes weak reflex movements 

 in both fore feet ; stronger in hind feet, especially in right. 



11.55. Acetic acid to right forearm caused vigorous kicks of 

 right hind leg. Acetic acid affected right leg in 10 seconds. 

 No motion in any other part of body. Acetic acid to left 

 forearm caused kicks in both hind legs, but much more 

 vigorous in the right. Also movement of left forearm by 

 itself, but weak. 



12.5. Acetic acid to left fore leg caused wriggling motion, 

 first in right hind leg and then in left fore leg in 16 seconds. 



