SNAKE-VENOMS. 473 



occurs the gland is compressed and the poison dis- 

 charged. 



By the arrangement of folds of mucous membrane round 

 the base of the tooth, as is well seen in the sea snakes 

 (Hydrophidae) , and especially in the cobra and viper, any 

 injury or loss of the fang does not affect the apparatus for 

 the transmission of the poison to the new tooth. 



Regarding the rate at which the venom is discharged, it 

 has been found by Nicholson that a cobra could not eject 

 through the fang with more force than would be necessary 

 to expel one drop in three seconds, so fine is the interior 

 orifice ; a viper, on the other hand, can eject much larger 

 quantities. The orifice is larger and the poison not nearly 

 so viscid as cobra poison. The writer has seen a specimen 

 of Russell's viper, when much irritated, ejects a fine stream 

 of poison to a distance of several feet. 



The poison, then, in cases of snake bite, is discharged 

 through the duct by the mechanical pressure of the 

 muscles which lie in the neighbourhood of the gland, and 

 are used in closing the jaws. Cases, however, are known 

 where the poison has been discharged reflexly from simple 

 pressure on the fang. The gentleman who was the writer's 

 co-worker in India was one day cleansing the mucus from 

 the mouth of a cobra, which was being held by a snake 

 charmer, preparatory to expressing the poison, when he 

 inadvertently pushed the top of his thumb against the 

 fang. He fancied that as the cobra had not bitten him 

 he had not received any poison, although the fang had 

 penetrated deeply ; he did no more, therefore, than suck 

 the wound. In about two hours he had weakness of the 

 limbs, drowsiness, vomiting, and was unable to feel in his 

 thumb and first two and a half fingers. The parts swelled, 

 and it was only after a considerable time that he recovered 

 by energetic treatment with Calmette's antivenine. He 



