52 ON THE NATURE AND ACTION OF THE 



Experiment XXIX. 



September 4th. — A cannula was placed in the carotid of a 

 large guinea-pig, and J c.c. of a 2-per-cent. solution of cobra- 

 poison injected into it towards the heart. The animal was 

 seized with violent convulsions, passing into complete opistho- 

 tonos in about 20 seconds after the injection of the poison. 

 These ceased, and the animal seemed quite dead in rather less 

 than a minute from the injection. The thorax was then opened. 

 The lungs were somewhat congested. The heart was quite still 

 in tetanic contraction. A strong interrupted current applied 

 to it caused no contraction of any of the fibres. The muscles 

 lost their irritability very quickly ; the intercostals of both sides, 

 and the serratus and subscapularis of the right side, seemed to 

 lose their irritability before the other muscles. 



When the poison is more slowly absorbed, so that a less 

 quantity of it circulates in the blood, its action on the muscles 

 is much less marked, as is evident from a comparison of the 

 irritability of those in the poisoned and non-poisoned limbs in 

 Experiments XXXYIT, XXXVIII, XXXIX, XLVII. If the 

 poison has undergone such changes as render it less active, it 

 has no action, or only a feeble one, on the muscles, as seen in 

 Experiments XI, XXX, XXXI, and XXXII, where poison, 

 which had undergone partial coagulation was employed. 



Experiment XXX. 



January 14th. — In order to test the local action of the poison 

 on the muscles and nerves, a ligature was tied round the base 

 of a frog's heart so as entirely to arrest the circulation. 



12.0. About a drop of cobra-poison was injected into one leg. 



1.30. Laid bare the lumbar nerves in the abdomen, and 

 irritated them by an induced current. Both legs contracted 

 nearly equally. 



Experiment XXXI. 



January 14th. — At 12.15. One or two drops of cobra-poison 

 were injected into the leg of a frog. The wound bled freely. 



