1874.] Poison of Indian Venomous Snakes. 103 



Action of Cobra-poison on Secreting Nerves. 



A notable symptom of cobra-poison in clogs is great salivation ; and 

 this might be supposed at first sight to indicate that the poison acted 

 as an irritant to the secreting nerves of the salivary gland. Nausea and 

 vomiting being also present, however, it is by no means improbable that 

 the salivation is due to the poison stimulating the secreting nerves of the 

 salivary glands not directly, but by reflex action, through the gastric 

 branches of the vagus. Unfortunately we are unable to say in which of 

 these ways salivation is induced, as we have not noted whether it 

 occurred after division of the vagus or not. So far as memory serves us, 

 we are inclined to think that it was much less in these cases ; but on this 

 point we cannot be at all positive. 



Whether cobra-poison has any stimulating action on secreting nerves 

 at first or not, it seems finally to paralyze them, or at least greatly to 

 diminish their power. 



This is evident from the following experiment. 



Experiment XLV. 



A dog was etherized and the chorda tympani exposed after its 

 separation from the lingual nerve. A cannula was then placed in the 

 duct of the submaxillary gland. On irritating the chorda by a weak 

 Faradic current, applied at intervals, saliva flowed freely. Some dried 

 cobra-poison dissolved in water was then injected into a vein in the leg. 

 Shortly afterwards the saliva began to flow much less freely than before ; 

 and although the current was increased in strength, only a small quantity 

 could be obtained. 



Action on Sensory Nerves. 



The sensory nerves seem to be little, if at all, affected by cobra-poison. 

 As appears from Experiment XXXVI. they retain their power after the 

 motor nerves are paralyzed; and Experiment XL VI. shows the compara- 

 tive effect of the poison and of want of blood both on the sensory and 

 motor nerves. The former were so little affected by the poison, that they 

 caused a ready response when those which had been deprived of blood had 

 nearly ceased to act. The motor nerves of the poisoned limb, on the con- 

 trary, were quickly paralyzed, while those of the ligatured one, although 

 doubtless weakened by the loss of their vascular supply, long retained 

 their irritability. In Experiment LX. the optic nerve and the aural and 

 buccal branches of the fifth nerve retained their irritability after the 

 cord had become nearly paralyzed ; and, in several experiments, reflex 

 actions could be induced by irritation of the cornea after voluntary motion 

 and respiration had ceased. 



Experiment XL VI. 



The right leg of a frog was ligatured, excluding the sciatic nerve, and a 

 concentrated solution of dried cobra-poison injected into the dorsal lymph- 

 sac at 2.3 P.M. 



