ADDERS. 87 
‘They are also occasionally found on the heaths near London and in 
the neighbourhood of Paris; they are met with at Montmorency, 
-and in the forest of Fontainebleau. ‘They feed upon lizards, frogs, 
molluscs, worms, insects, and small mammalia, such as field-mice, 
shrews, and moles. They pass the winter and early spring in deep 
hcllows, in a state of torpor, where they are sheltered from the cold. 
It is not unusual to find several adders coiled up together in one 
heap, entwined and interlaced together.* | 
The movement of Adders is abrupt, slow, and irregular. They 
appear to be shy and timid creatures, shunning the day, and only 
seeking their food in the evening. The young come into the world 
alive ; so long as they are maintained within the mother, they are 
enclosed in eggs with membranous shells. Soon after their birth the 
young Vipers, whose length does not exceed six or seven inches, are 
abandoned by the parent, and left to shift for themselves. They do 
not, however, acquire their full development till they are six or 
seven years old. Adders are justly considered objects of fear and 
horror both to men and to other animals, as they bear with them 
a formidable apparatus, of which it is important that both the 
structure and the mode of action should be known. ‘This venomous 
apparatus is composed of three parts—the secreting glands, the 
canal, and the hooked fangs. 
The gland is the organ which secretes the venom; it is situated 
upon the sides of the head, behind and a little beneath the globe of 
the eye; it is formed ofa number of inflated bladders, composed of 
a granulous tissue, and disposed with great regularity along the 
excretory canal, not unlike the barbs of a pen-feather. This arrange- 
ment, however, is only visitie through a microscope. The tube 
destined to conduct the secreted venom through the gland is straight 
and cylindrical ; after being filled, in its short journey it ends in 
two peculiar hook-like teeth, called fangs, tapering to a point, and 
horn-fike. They are much longer than the others, and placed one to 
the right, the other to the left, of the upper jaw. The adder, then, is 
furnished with two of these poison-fangs ; they are curved and sharp- 
pointed, convex anteriorly, and furnished with a straight duct which 
commences in one part bya slit placed at the anterior part of its 
base, terminating by a second and smaller cleft towards its point, 
and on the same side. ‘This last cleft is like a little trench or fine 
furrow, which extends the whole length of its convexity. These 
hooked teeth are surrounded by a fold of the gums, which receives 
* In the Highlands of Scotland I have twice observed thisx—ED. 
