70 ON THE NATURE AND ACTION OF THE 



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 paralyse them, or at 

 least greatly to diminish their power. 



This is evident from the following experiment. 



Experiment XLV. 

 A dog was etherised 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 paralysed; and 

 Experiment XLVI shows the comparative 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 contrary, were quickly paralysed, 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 



