15 



into the fang and through it into the wound. But if there 

 be no obstacle to pucker up "the mucous envelope, then the 

 poisonous saliva finds its way into the mouth just like the 

 saliva of the other glands, running down the inside of the 

 gingival fold along the outer surface of the fang. I have 

 seen the saliva ejected by an enraged cobra in quantities 

 which could not have passed through the fang, for experi- 

 ments enable me to affirm that a cobra could not inject 

 through the fang with more force than would be necessary 

 to expel one drop (a minim) in three seconds, so fine is the 

 inferior orifice of the fang. A viper, however, could inject 

 the same quantity in half a second, and fluid may be forced 

 through its fang in a fine stream, whilst small single drop- 

 lets can alone be ejected from the cobra's fang. 



The poison of the venomous snakes is secreted by the 

 large parotid gland. But a curious observation has been 

 made by Mayer and corroborated by Mr. Stolicska of the 

 Indian Geological Survey, that a species of Callophis (C. 

 intestinalis) has supplementary poison glands in the 

 thoracic cavity ; they extend one-third down the body, keep- 

 ing close to the gullet on the ventral side, and reach as far 

 as the heart where they are thicker than above. I am not 

 aware, however, of any experiments as to the character of 

 the secretion furnished by this gland. I suspect it is a 

 salivary gland to the gullet. 



There is no difficulty in forcing a venomous snake to yield 

 the poison accumulated in the parotid glands. Pressure on 

 the glands while the fangs are erected over the edge of a 

 watch-glass will cause a flow of the saliva, generally in large 

 drops from between the fang and the mucous envelope, 

 more rarely in a fine jet from the apical orifice of the 

 fang. This is a viscous yellowish fluid, of faintly acid 

 re-action ; exposed to the air it dries rapidly, the film cracking 

 all over and thus separating into yellow crystals not unlike 



