108 Messrs. T. L. Brunton and J. Fayrer on the [Jan. 22, 



to the cause of death when a considerable quantity of poison enters the 

 arterial system at once. In warm-blooded animals, as is shown by Ex- 

 periment LXVIIL, the heart is arrested, in many instances, and death thus 

 occasioned; but when this is not the case, the appearance of paralysis is 

 probably due to affection of the nerve-centres. 



Experiment L. 



Sept. 13th. A ligature was placed round the middle of a frog, excluding 

 the lumbar nerves. 



3 P.M. Some dried cobra-poison dissolved in water was injected into the 

 dorsal lymph-sac. Immediately after the injection the animal could move 

 all its limbs quite well. 



3.3. Eestless ; moves all its limbs. 



3.17. Can still move vigorously. 



3.21. Can kick vigorously with its legs, especially the right. "When 

 it moves it seems to overreach itself and turns over, apparently from 

 the hind limbs remaining unaffected and the arms becoming partially 

 paralyzed. 



3.40. Still moves voluntarily. 



3.52. No reflex motion can be produced by touching any of the ex- 

 tremities with acetic acid. 



A minute or two afterwards a slight twitch was noticed in one arm, to 

 which acetic acid had been applied ; but whether this was greatly delayed 

 reflex action caused by the acid, or whether it was due to something else, 

 is uncertain. A needle was now run down the spinal cord. It produced 

 no effect. 



The legs contracted readily when the lumbar nerves were irritated. 



The absence of motion in the legs when the cord was irritated by a 

 needle run down the spinal canal, shows that the power of the cord to 

 originate motor impulses had been destroyed, as it would usually have 

 caused violent contractions in the extremities. These having been pro- 

 tected from the action of the poison either on muscle or nerve, would 

 respond readily, as indeed they did, to voluntary motor impulses shortly 

 before the death of the animal. 



Experiment LI. 



May 12th, 1873. The sacrum of a frog was removed, and a ligature 

 passed round the body, excluding the lumbar nerves. There was a good 

 deal of bleeding. 



12.30. Ligature tied. 



12.33. A good dose of dried cobra-poison dissolved in water was intro- 

 duced into dorsal lymph-sac. Immediately afterwards the frog sprung 

 about once or twice. 



1.27. Cornea insensible. On pinching the finger of either hand, it kicks 

 out vigorously with the right hind leg. On squeezing the toes of right 

 hind foot it kicks out vigorously with it. On squeezing toes of the left 



