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



in the trachea and artificial respiration begun. Sciatic nerve isolated. Irri- 

 tated by induced current. Foot twitched when secondary coil was at 57 

 centimetres. 



About 6.30. Electrodes screwed into cord about 2nd and 5th dorsal 

 vertebrae. 



The strongest current of the coil produced contraction of the muscles 

 of the back, but no contraction of the limbs. The sciatic nerve, when 

 irritated directly, caused contraction of foot with the coil at 23. 



6.50. The phrenic nerve irritated ; no contraction of diaphragm ; vagus 

 irritated ; heart stopped. 



In this experiment the continuance of reflex action on irritation of the 

 ear, and of voluntary movements, after reflex action on irritation of the 

 eye had disappeared, and almost up to the time of death, are remarkable ; 

 as is also the paralysis of the phrenic before the sciatic and vagus nerves. 



Action of Cobra-poison on the Circulation. 



In most cases of death from cobra-poison, the fatal issue is not to be 

 attributed to any failure of the circulatory apparatus ; for the heart 

 continues to pulsate vigorously, long after all motions have ceased in the 

 voluntary muscles and the strongest irritation applied to the spinal cord 

 and motor nerves fails to produce the slightest effect. But this only 

 occurs when the dose of poison is not excessive ; and when a large quantity 

 of it is introduced, at once, into the circulation, the heart is not exempted 

 from its action, but is, on the contrary, most seriously affected. This is seen 

 in Experiments LXVIII. and XXVIII., where the poison having been 

 either injected into the circulation, or absorbed with extreme rapidity, the 

 action of the heart was at once arrested. But it is to be noted that it is 

 not paralysis, but tetanic contraction of the heart which is produced, 

 the poison, in fact, seeming to act as an excessive stimulus ; and this being 

 the case, we feel less surprise on finding that, in ordinary cases of poison- 

 ing, the cardiac action may be maintained by the use of artificial respira- 

 tion for more than thirty hours, as Mr. Richards has succeeded in doing 

 in India. The cardiac movements cease much sooner in frogs poisoned 

 by cobra-venom than in those paralyzed by curare the pulsations in the 

 latter often continuing for very many hours, or even for one or two days. 

 They are also arrested by the direct application of the poison to the heart, 

 as in Experiment LXXII. Its action seems to be somewhat different in 

 degree, if not in kind, when applied to the outside of the heart, as in 

 Experiment LXX., and to the inside, as in Experiment LXXII. ; for in 

 the former case the pulsations continued for a considerable time, while in 

 the latter they were instantly arrested, the heart stopping in partial systole 

 and moderately contracted. 



The action of cobra-poison being exerted on the heart of the frog after 

 its excision, shows that it acts on the heart itself ; and its effect being 

 very much the same without the body as within it renders it probable 



