THE ADDER. 251

much in the same manner that the classical ancients resorted
on similar occasions to the serpent symbol of the healing
god Aisculapius.

“Tn all venomous serpents, there is a gland near the
eye for secreting the poisonous fluid, which is conveyed in
a small tube to the end of a fang, which in a state of rest
reclines backwards along the margin of the jaw, and is
covered by a fold of skin, but when used, it is erected by
means of a small muscle. The poisonous fluid is inodorous,
tasteless, and of a yellow colour; when the animal inflicts a
wound, the pressure on the tooth forces a small drop of
poison through the orifice of the tooth, which flows into the
wound. The manner in which the blow is struck is as
follows : the animal generally throws itself into a coil, more
or less close, and the anterior part of the body is raised ;
the neck is bent somewhat abruptly backwards, and the
head fixed almost horizontally ; in an instant the head is, as
it were, launched by a sudden effort towards the object of
its anger, and the erected tooth struck into it with the velo-
city of thought. It is found by experience that the effect
of subsequent wounds is greatly diminished, either by the
diminution of the quantity of venom, or by the deterioration
of its strength, so that if a venomous serpent be made fre-