POISON OF SOME INDIAN VENOMOUS SNAKES. 97 



The inhibitory branches of the vagus are not always 

 paralysed (Experiment LXVI) ; but sometimes the cobra-poison 

 appears to affect them as well as the motor nerves ; and in this 

 it resembles curare, which in small doses does not impair the 

 inhibitory action of the vagus, but in large doses completely 

 destroys it. In Experiment LVI irritation of the vagus 

 quickened, instead of retarding, the cardiac pulsations — 

 a circumstance which indicates that the inhibitory fibres of the 

 vagus were paralysed by the poison, but not the accelerating 

 ones. 



The capillary circulation is not unaffected by the poison. In 

 Experiment IV of our former paper, the rhythmical contrac- 

 tions and dilatations, altogether independent of the cardiac 

 pulsations, which Schiff first observed in the rabbit's ear, and 

 which were noticed by Ludwig and Brunton in the vessels of 

 many parts of the body, were greatly increased by the injection 

 of the poison. 



In Experiments LXXIV and LXXV the blood-pressure 

 remained high after the heart had ceased to beat. This shows 

 that the arterioles, or capillaries, must have been much con- 

 tracted, thus opposing a barrier to the exit of blood from the 

 arteries into the veins. 



Experiment LXVI I. 



May 21st. — A cannula w^as placed in the trachea of a large 

 black rabbit ; and some dried cobra-poison dissolved in water 

 was injected into the hip at 1.25 p.m. 



1.50. The animal shows symptoms of poisoning. Limbs 

 becoming weak. There is trembling, and the body sinks down. 

 There is starting. The respiration is hurried. 



2. Eeflex action is well marked when the animal is touched. 

 The limbs seem almost paralysed ; but the animal moves the 

 head and neck freely. It makes efforts to rise, but is unable to 

 do so. The head falls over ; the respiration is getting feeble. 

 The animal seems quite conscious, and starts if touched. 



2.4. It is now quite feeble. When the cornea is touched the 

 reflex action is less than before. 



2.5. ISTo convulsions. Artificial respiration commenced. The 

 (95) H 



