The asp also, and other serpents, have similar teeth; but in the upper jaw, on the right and left, they have two of extreme length, which are perforated with a small tube in the interior, just like the sting of the scorpion, and it is through these that they eject their venom. The writers who have made the most diligent enquiries on the subject, inform us that this venom is nothing but the gall of the serpent, and that it is conveyed to the mouth by certain veins which run beneath the spine; indeed, there are some who state that there is only one poison-fang, and that being barbed at the end, it is bent backwards when the animal has inflicted a bite. Other writers, however, affirm that on such an occasion the fang falls out, as it is very easily displaced, but that it soon grows[226] again; this tooth, they say, is thus wanting in the serpents which we see handled about by persons.[227] It is also stated that this fang exists in the tail of the scorpion, and that most of these animals have no less than three. The teeth of the viper are concealed in the gums: the animal, being provided with a similar venom, exercises the pressure of its fangs for the purpose of instilling the poison in its bite. No winged creatures have teeth, with the sole exception of the bat. The camel is the only one among the animals without horns, that has no fore-teeth[228] in the upper jaw. None of the horned animals have serrated[229] teeth. Snails, too, have teeth; a proof of which are the vetches which we find gnawed away by snails of the very smallest size. To assert that among marine animals, those that have shells, and those that are cartilaginous have fore-teeth, and that the sea-urchin has five teeth, I am very much surprised how such a notion could have possibly[230] arisen. With insects the sting supplies the place of teeth; the ape has teeth just like those in man.[231] The elephant has in the interior of the mouth fourteen teeth, adapted for chewing, in addition to those which protrude; in the male these are curved inwards, but in the female they are straight, and project outwards. The sea-mouse,[232] a fish which goes before the balæna, has no teeth at all, but in place of them, the interior of the mouth is lined with bristles, as well as the tongue and palate. Among the smaller land quadrupeds, the two fore-teeth in each jaw are the longest. CHAP. 63.—WONDERFUL CIRCUMSTANCES CONNECTED WITH THE TEETH.