An attempt was also made to introduce our common snake, but
the country-people, with great horror, killed the inlopers; a reward
even was offered for one that was known to remain uncaptured. Ireland is
free from adders.

The most ready distinction between a common snake and an adder, to
unfamiliar eyes, is founded on the difference of marking. While the
snake has separate alternate spots, the adder has, down its back, a
chain of dark spots, irregularly square, and joined to one another.
Adders are generally brown, but differ very much in color. They have on
their upper jaw, instead of their lower, a row of teeth, the well-known
fangs. These are long, curved teeth, fixed into a movable piece of bone,
and hollow. The hollow is not made out of the substance of the tooth; it
is as if a broad flat tooth had been bent round upon itself to form a
tube. The tube is open below and behind, in the curve, by a little
slit. Above, it is open, and rests upon a tiny bag connected with a
gland that corresponds to a gland in man for the secretion of saliva;
but which, in the present case, secretes a poison. The fang, when out of
use, is bent and hidden in a fleshy case; in feeding, it is rarely used.
The viper catches for himself his birds or mice, after the manner of a
harmless serpent. But, when hurt or angered, he throws back his neck,
drops his fang ready for service, bites, and withdraws his head
immediately. The fang in penetrating, of necessity, was pressed upon the
little bag of poison at its root, and forced a drop along the tube into
the wound. After a few bites, the bag becomes exhausted, and the adder
must wait for a fresh secretion. The poison has no taste or smell, and
may be swallowed with impunity, if there be no raw surface in the mouth,
or sore upon the throat, or in the stomach. It is only through a wound
that it can act like poison. The bite of an adder in this country never
yet proved fatal; but, according to the health of the person bitten, and
according to the greater or less heat of the weather (for in very hot
weather a more active poison is secreted), the wound made will be more
or less severe. It is advisable to get out of an adder's way.

All the remaining reptiles in this country are two species of Frog, two
species of Toad, and four Newts. They are not only most absolutely
harmless, but, the frogs, at any rate, and toads, are ministers to man;
and they belong to a class of animals more interesting than any