506 poisons : their effects and detection. [§ 663. 
this oil is not blister-raising. Cantharides in powder may, of course, 
be detected by its appearance. 
To the question whether the method proposed would extract any 
other blister-producing substance, the answer is negative, since ethereal 
oil of mustard would be decomposed, and the active constituents of the 
Euphorbias do not withstand the treatment with KHO. Oils of 
anemone and anemonin are dissolved by KHO, and again separated 
out of their solutions ; but their blistering property is destroyed. They 
are volatile, and found in anemone and some of the Ranunculacece. In 
the Aqua pulsatilla there is an oil of anemone, which may be obtained 
by shaking with ether ; but this oil is not permanent, and if the Aqua 
pulsatilla stand for a little time, it splits up into anemonic acid and 
anemonin, and then cannot be reobtained. A blistering substance 
obtained from the Anacardia orientalia and the fruit of the Anacardium 
occidentale and Semecarpus anacardium, is not quite destroyed by a 
short action with potash, but is by one of long duration ; this substance, 
however, cannot be confused with cantharidin, for it is oily, yellow, 
easily soluble in alcohol and ether, and differs in other respects. 
V.—Poisonous Snakes. 
§ 663. The poisonous snakes are classified as follows :— 
A. COLUBRIDiE, VENENOS^E. 
I. Opistoglypha (suspected snakes, “ serpentes suspecti ”).—Furrowless 
teeth in the fore-part of the upper jaw, behind one or several poison 
fangs. They are almost all poisonous, but seldom dangerous to man 
or the larger animals. They are represented by Homalopsince, the 
water snakes ; Dipsadomorphince, whip snakes ; and Elachistodontince. 
II. Proteroglypha. —Furrowed teeth. The teeth in the fore-part of 
the upper jaw are provided with a deep groove or furrow, in combination 
with very often highly developed poison glands. This division includes 
the sea-snakes Hydrophince and the Elapince. 
R Viperidje. 
I. Crotalince (pit vipers).—Head very broad. O 11 both sides of the 
head, between the eyes and nostrils, a deep depression or pit ; hence the 
name. 
II. Viperince (vipers).—Head very broad, but possessing no pit like 
the Crotalince. 
The Opistoglyphce are poisonous to small animals, and species belong¬ 
ing to this order have occasionally caused illness in man. 1 
1 J. J. Quelch, Proceedings of the Zoological Society , 1898. 
