Page:Natural History, Reptiles.djvu/213

Rh dangerous. Several circumstances affect the result of a poisoned wound; the injection of the venom into an artery, the heat of the weather, the more direct and forcible character of the stroke, the vigour of the reptile, the time that has elapsed since it last exerted its powers, and the debility of the sufferer, are all important circumstances.

We have already described the peculiar structure of the gland by which this deleterious fluid is secreted from the blood, and accumulated; and we now quote from the distinguished zoologist to whom these pages are so much indebted, an account of the interesting mechanism by which it is injected into the wound.

“It will not perhaps be wholly uninteresting,” observes Professor Bell, “to describe the very beautiful apparatus by which the poison wounds are inflicted, which render these, and so many other Serpents, so formidable. On each side of the upper jaw, instead of the outer row of teeth which are found in non-venomous Serpents, there exist two or three, or more, long, curved, and tubular teeth, the first of which is larger than the others, and is attached to a small movable bone, articulated to the maxillary bone, and moved by a muscular apparatus, by which the animal has the power of erecting it. In a state of rest, the fang reclines backwards along the margin of the jaw, and is covered by a fold of skin; but when about to be called into use, it is erected by means of a small muscle, and brought to stand perpendicular to the bone. The tooth itself is, as it were, perforated by a tube, the mode of formation of which, was not understood until it was