in zoology, a genus of serpents belonging to the order of amphibia. The characters are these: they have a number of scuta, or hard crusts on the belly; and scutellae, or scales on the tail. Linnaeus enumerates no less than 97 species under this name, distinguished solely by the number of scuta and scutella. The most remarkable are the following:

1. The Vipera, or common viper of the shops, has 118 scuta, and only 22 scutellae. The body is very short, and of a pale colour, with brownish spots; and the head is gibbous, and covered with small scales. It is a native of Egypt, and other warm countries. It has always been remarkable for its poisonous nature; inasmuch that vipers, when numerous, have often been thought the ministers of divine vengeance, like the plague, famine, and other national calamities. A notion also prevailed among the ancients, that few or none of the parts of a viper were free from poison; for which reason they made no experiments or discoveries concerning the nature of these creatures. It is now, however, proved, by undoubted experiments, that the poison of vipers, as well as of all other serpents whose bite is hurtful, lies in a bag at the bottom of their two greater teeth or fangs. These teeth are perforated; and when the creature bites, the compression of the bag forces out a little drop of the poison into the wound, where it produces its mischievous effects. Dr Mead has given a curious anatomical dissection of those parts of a viper which have any connection with its poison, by which the truth of the above mentioned position is ascertained beyond a doubt. With regard to the poison itself, Dr Mead says its quantity is so inconsiderable, that one good drop does all the execution. When viewed through a microscope, the liquor had a saline appearance. At first he perceived only a quantity of minute salts nimbly floating here and there: but in a very short time the appearance was changed; and these saline particles were now shot out into crystals of extreme tenacity and sharpness, with something like knots here and there, from whence they seemed to proceed: so that the whole texture did, in some measure, resemble a spider's web, though infinitely finer. He made various experiments in order to determine the quality and species of these crystals, but without effect. Half an ounce of human blood, newly drawn, was not visibly altered, either in colour or consistence, by a mixture with the poison. It then was, and remained, undistinguishable from the same blood taken into another glass in which there was no poison. These portions of blood were severally mixed with acids and alkalies: the empoisoned blood was, after such mixtures, of the same colour and consistence with the other. Spirit of nitre, spirit of salt, and juice of lemons, severally poured upon the salines itself, produced neither fermentation, nor any change of colour.

Oleum tartari per deliquium, and the simple spirit of hartshorn, dropped upon the poison, neither altered its colour, nor raised any ebullition. Syrup of violets mixed with the poison did not change its colour either to red or green. The tincture of heliotropium, that is blue paper, was not altered by the salines ejected upon it: and this drying still retained its yellowish colour. These experiments were tried by Dr Mead, in presence of a number of gentlemen. They ended their inquiries by tasting the poisonous liquor. Having diluted it with a little warm water, several of them ventured to touch it with the tip of their tongues. They all agreed that it tasted very sharp and fiery, as if the tongue had been struck through with something scalding or burning. This sensation went not off in two or three hours; and one gentleman who would not be satisfied without trying a large drop undiluted, found his tongue swelled with a little inflammation, and the foretaste lasted two days; but without any farther inconvenience. The purpose answered by this poisonous liquor to the creatures themselves, is probably the destruction of their prey; for as serpents frequently feed upon animals of very considerable magnitude and strength, they would often undoubtedly make their escape, did not the poisonous juice infilled into the wounds made by the serpent's teeth almost instantly deprive them of life, or at least of all power to struggle with their enemy. For an account of the symptoms produced by the bites of vipers and other venomous serpents in the human body, together with the best methods of cure, see the Index subjoined to Medicine. After the viper is deprived of these bags which contain its poison, it is entirely harmless: nay the flesh of it is highly nutritive, and justly esteemed a great restorative. It hath been much recommended in scrophulous, leprous, and other obstinate chronic disorders; but, to answer any good purpose, it must undoubtedly be used for a considerable time as food. The dried flesh which comes to this country from abroad, is justly esteemed by Dr Lewis to be totally insignificant. A volatile salt was formerly drawn from vipers, and sold at a great price, as a sovereign remedy against the bites of vipers and other poisonous animals; but it is now found not to be materially different from the volatile alkaline salts procured by distilling other animal substances.

2. The berus, or common British viper, is found in many countries of Europe. They swarm in the Hebrides, or western British isles, and abound in many parts of Britain; particularly in the dry, flinty, and chalky counties. According to Mr Pennant and other naturalists, they are viviparous, but proceed from an internal egg; being of that class of animals of whose generation Aristotle says, "They conceive a perfect egg within, but bring forth their young alive." This species is far from being prolific; 11 eggs being the utmost that were ever heard of in one viper. These eggs are, as it were, chained together; and each about the size of the egg of a black-bird. This viper seldom grows longer than two feet; though Mr Pennant tells us he once saw a female (which is nearly a third larger than the male) almost three feet long. The ground colour of this serpent is of a dirty yellow, that of the female deeper. Its back is marked the whole whole length with a series of rhomboidal black spots, touching each other at the points; the sides with triangular ones; the belly entirely black. It hath 146 scuta, and 39 scutellae. There is a variety wholly black; but the rhomboid marks are very conspicuous even in this, being of a deeper and more glossy hue than the rest. The head of the viper, says Mr Pennant, is inflated, which distinguishes it from the common snake. Mr Catesby affirms us, that the difference between the vipers and other serpents is, that "the former have long hollow fangs, or tusks, with an opening near the point; the neck is small, the head broad, the cheeks extending wide, scales rough, the body for the most part flat and thick; they are slow of motion; I well the head and neck when irritated, and have a terrible and ugly aspect." The tongue is forked, the teeth small; the four canine teeth are placed two on each side the upper jaw: these instruments of poison are long, crooked, and moveable; capable, like those of the former species, of being raised or depressed at the pleasure of the animal, and they instill their poison in the same manner. The vipers are said not to arrive at their full growth till they are six or seven years old; but they are capable of engendering at two or three. They copulate in May, and go about three months with their young. Mr Pennant tells us, that he has been assured of a fact mentioned by Sir Thomas Brown *, who was far from being a credulous writer, that the young of the viper, when terrified, will run down the throat of the parent, and seek shelter in its belly, in the same manner as the young of the opossum retire into the ventral pouch of the old one. From this some have imagined that the viper is so unnatural as to devour its own young: but this assertion deserves no credit; it being well known that the food of these serpents is frogs, toads, lizards, mice, and, according to Dr Mead, even an animal so large as a mole. These they swallow entire; which, if we consider the narrowness of their neck, shows it capable of a diffusion hardly credible, had we not ocular proofs of the fact. It is also said, from good authority, that they will prey on young birds; but whether on such as nestle on the ground, or whether they climb up trees for them, as the Indian serpents do, is quite uncertain: the fact, however, is very far from being recent; for Horace tells us,

Ut affident implumbibus pallis aves Serpentium allegatis timet. Epod. I.

Thus for its young the anxious bird The gliding serpent fears.

The viper is capable of supporting very long abstinence; it being known, that some have been kept in a box six months without food, and yet did not abate of their vivacity. They feed only a small part of the year, but never during their confinement; for if mice, their favourite diet, should at that time be thrown into their box, though they will kill, yet they never will eat them. The violence of their poison decreases in proportion to the length of their confinement, as does also the virtue of their flesh whatever it is. The animals, when at liberty, remain torpid throughout the winter; but, when confined, have never been observed to take their annual repose. The method of catching them is by putting a cleft stick on or near their head; after which they are seized by the tail, and instantly put into a bag. The viper-catchers are very frequently bit by them in the pursuit of their business, yet we very rarely hear of their bite being fatal. Sallad oil, if applied in time, is said to be a certain remedy *. The flesh of the British viper has been celebrated as a restorative, as well as that of the foreign kind. Mr Keyller relates, that Sir Kenelm Digby used to feed his wife, who was a most beautiful woman, with capons fattened with the flesh of vipers.

3. The punctatus of Linnaeus, by Mr Catesby called the water-viper, is a native of Carolina. According to Linnaeus it is ash-coloured, variegated with yellow spots. Mr Catesby informs us, that the head and back of this serpent are brown; the belly marked transversely with yellow, and also the sides of the neck. The neck is small, the head large, and the mouth armed with the destructive fangs of the viper or rattle-snake, next to which it is reckoned the largest serpent in this country. Contrary to what is observed in most other vipers, these are very nimble and active, and very dextrous in catching fish. In summer, great numbers are seen lying on the branches of trees hanging over rivers; from which, on the approach of a boat, they drop into the water, and often into the boat on the men's heads. They lie in wait in this manner to surprize either birds or fish: after the latter they plunge with surprising swiftness, and catch some of a large size, which they bring ashore and swallow whole. The tail of this animal is small towards the end, and terminates in a blunt horny point about half an inch long. This harmless little horn hath been the occasion of many terrible reports; as, that by a jerk of its tail, the animal is capable of instantly destroying both men and beasts; that a tree struck with this terrible horn, in a short time grows black, withers, and dies, &c. but all these Mr Catesby affirms us have not the least foundation in fact.

4. The cherlea is a native of Sweden, where it is called asping. It is a small reddish serpent, whose bite is said to be mortal. Concerning this species Mr Pennant asks, "Is it possible that this could be the species which has hitherto escaped the notice of our naturalists? I rather suspect it, as I have been informed that there is a small snake that lurks in the low grounds of Galloway, which bites and often proves fatal to the inhabitants."

5. The prester of Linnaeus, or black viper of Mr Catesby, is a native of Carolina and Virginia. It is short and thick, slow of motion, spreads its head surprisingly when irritated, very flat and thick, threatening with a horrid hiss. They are very poisonous; their bite being as deadly as that of the rattlesnake. They frequent the higher lands, and are of a rusty black colour.

6. The coluber luridus of Forskål, called by Mr Catesby the brown viper, is a native of the same countries with the preceding. It is about two feet long, and large in proportion; very slow in its motion, even when threatened with danger: notwithstanding which, it defends itself very fiercely when attacked, and its bite is as venomous as any. They prey upon efts, lizards, and other animals of that kind. Besides these species of which we have a particular description, the following are also reckoned among the poisonous serpents, viz. 7. The atropos, with 131 scuta and 22 scutellae. It is a native of America, the body white, and the eyes brown, with a white iris. 8. The leberis, with 110 scuta and 50 scutellae, is a native of Canada, and has many black linear rings. 9. The ammodites, with 142 scuta and 32 scutellae, is a native of the East. It is about six inches long, and has a fleshy protuberance on its nose. 10. The apis, with 146 scuta and 46 scutellae, is a native of France; and is of a reddish colour, with dusky spots on the back. 11. The lebetinus, with 155 scuta and 46 scutellae, is a native of Asia, and is of a cloudy colour, with red spots on the belly. 12. The feverus, with 179 scuta and 42 scutellae, is likewise a native of Asia, and is ash-coloured with white belts. 13. The stola tus, with 143 scuta and 76 scutellae, is a native of Asia; and is of a greyish colour, with two white fillets. 14. The lacteus, with 203 scuta and 52 scutellae, is a native of the Indies. Its colour is white, with black spots. 15. The naja, with 193 scuta and 60 scutellae, is a native of the East Indies, and is reckoned the most poisonous of all serpents. It is killed by the ichneumon. 16. The atrox, with 196 scuta and 69 scutellae, is a native of Asia. It is of a hoary colour, and the head is compressed and covered with small scales. 17. The niveus, with 259 scuta and 62 scutellae, is a native of Africa. It is white, and without any spots. 18. The corallinus, with 193 scuta and 82 scutellae, is a native of Asia. It is greyish, with three brown fillets. 19. The diplas, with 152 scuta and 135 scutellae, is a native of America. It is of a bluish colour, with the margins of the scales white. 20. The mycterizans, with 192 scuta and 167 scutellae, is a native of America. It hath a stretched out triangular snout.

The above 20 species are all the serpents of the genus of coluber that are reckoned poisonous. Of the rest we shall only mention the following, which are the most remarkable.

21. The erythrogaster of Forster, called by Mr Cateby the copper-bellied snake, is a native of Carolina, and grows sometimes near to the size of a rattlesnake. It is of a brown colour in all parts of its body, except the belly which is of a red copper colour. They frequent water, and probably prey on fish; but they will also devour birds and such other animals as they are able to overcome. They are bold and active, frequently entering poultry-houses, devouring the fowls and sucking their eggs.

22. The constrictor, or black snake, is a native of several parts of America. They are very long, sometimes measuring six feet, and are all over of a shining black. They are the most numerous of all; and are very bold and furious, leaping at and biting those that attack them. It is commonly said, that they will attack and devour rattlesnakes. This Mr Cateby says he cannot affirm as truth from his own experience; but affirms us, that large serpents of any species will very often swallow the smaller ones indiscriminately. The black snakes are preferred on account of their dexterity in destroying rats; which animals they pursue to their hiding places in the roofs of houses, &c., with wonderful agility.

23. The annulatus, or little brown bead-snake, is always small, and is seldom found above ground, but commonly dug up, and found twisting about the roots of shrubs and plants. All the back and other parts of the body have transverse spots of brown and white so disposed as to have some resemblance to a string of English beads; whence probably it takes its name. It is quite harmless, and is a native of Virginia and Carolina.

24. The flagellum, or coach-whip snake, is of a brown colour, very long, slender, and active. It runs swiftly, and is quite inoffensive; but the Indians imagine it is able to cut a man in two with a jerk of its tail.

25. The fulvius, or corn-snake, is beautifully marked with red and white, resembling a species of Indian corn, whence its name. It is harmless as to its bite, but frequently robs hen-roosts.

26. The vitivus, or green snake, is all over of a green colour; it is of a small size, and easily becomes tame and familiar, infomuch that some people will carry them in their bosom.

27. The fasciatus, or wampum snake, derives its name from its resemblance to the Indian wampum. It sometimes grows to the length of five feet; and, like other large snakes, is very voracious, but its bite is not venomous. The back is of a dark blue, the belly finely clouded with spots of a brighter blue; the head is small in proportion to the rest of the body.