THE VENOMOUS SNAKES OF INDIA.

In a previous article an account was given of the carnivora and other wild beasts which are destructive to life in British India; of the mortality caused by them in those provinces which have furnished statistical records of the death-rates, of the rewards paid by Government for the destruction of the noxious creatures, and of the numbers destroyed, with a brief notice of the measures in force for abating the evil.

It was shown that the average loss of life caused by wild animals and venomous snakes combined has for eight years been at the rate of 22,620 human beings and 53,277 head of cattle annually, and that it has continued at about the same rate, with slight fluctuations, up to the present date, notwithstanding such measures as may have been resorted to for its prevention. It was also shown that of these deaths those of 2,740 human beings and 51,180 head of cattle and other domestic animals were due to wild animals alone, whilst the much larger number of 19,880 deaths of human beings, and the smaller of 2,100 of cattle were ascribed to venomous snakes of different kinds. The smallest numbers killed by wild beasts and snakes combined, recorded in the eight years cited, were in 1881, when 21,427 human beings and 43,669 cattle were killed; the largest figures were in 1886, when 24,841 men, and in 1887, when 63,737 cattle were killed.

In this paper I propose to describe the reptiles which cause these deaths, to give some account of the circumstances under which they exert their lethal power, to notice the measures in operation for preventing the evil, and to make a brief reference to the nature and physiological action of the virus which is so fatal.

The provinces referred to represent, roughly, about five-eighths of the peninsula, and the population about 199,000,000, or sevenninths of a total population of 256,000,000; both are the same as those referred to in the former paper. The thirteen groups of native states forming Feudatory India, with the French and Portuguese possessions, having a population of 57,000,000, are excluded from the above calculations.

In describing the venomous snakes of India I shall dwell at any length on those only which are most destructive to life, e.g. the Naja or Cobra, the Ophiophagus or Hamadryad, the Bungarus or Krait, the

Daboia or Russell's viper, and the Echis carinata or Kuppur. The crotaline snakes, though all poisonous, are comparatively innocuous, as far as human life is concerned. Some notice will also be taken of the hydrophidae or sea snakes which, though, exceedingly poisonous, are not very destructive to human life.

I regret that I am unable to assign to each species its individual share in the death-rate, as no reliable returns of this particular form of detail are available. The deaths, whatever their numbers may are recorded under the general head of 'poisonous snakes.'

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India is richly supplied with both venomous and innocuous snakes; with the latter we are not here concerned.

The order Ophidia has two principal subdivisions, the colubriform and the viperiform. The first is divided into the venomous and innocuous. The second or viperiform are all venomous. Both the colubrine and viperiform are numerously represented in India; the colubriform by five genera of elapidæ and four of hydrophidæ, the viperiform by two genera of viperidæ and four of crotalidæ, making a total of fifteen poisonous genera, comprising a large number of species and varieties. But large as the number is, it is small compared with the innocent genera and species contained in about seventeen families of innocent colubriform snakes inhabiting the same country.

Snakes are pretty generally distributed over the globe wherever climate and other physical conditions are favourable to their existence, but tropical countries are most richly supplied, and in the hottest regions the most venomous are found. In our own islands, the common adder is the only venomous snake, and its power is feeble compared with that of the snakes of India, the West Indies, Tropical America, Africa, and Australia, where the largest and most deadly forms are found in great variety. The most widely distributed venomous snakes are the viperiform; America and Africa abound in them, the crotalidæ being most numerous in the former, the true vipers in the latter, whilst in Asia the poisonous colubrine snakes are most numerous and are represented by the Najas, Bungarus, Callophis, and the hydrophide. The true vipers, on the other hand, are represented by Daboia and Echis, whilst the crotalidæ or pit vipers are represented by Trimeresurus, Hypnale, Halys; Australia has its peculiar forms of both colubriform and viperiform genera.

The general characters of Ophidia are well known, and therefore need only a few remarks on the distinctive characters of the venomous, as contrasted with the innocent forms, with a brief notice of the apparatus by which the virus is secreted, and of the fangs by which it is inoculated.

Snakes are oviparous or ovoviviparous; the colubrine snakes for the most part belong to the first class,-the cobra, for example, lays eggs; there are exceptions, however, such as hydrophida and homolop

side, which bring forth their young alive. The viperine-e.g. the daboia, the adder, the rattle-snake-are viviparous. There are exceptions, as some Trimeresuri are oviparous, it is said, but there is no great physiological distinction after all, the question being whether the eggs are hatched before or after leaving the oviduct. The progeny is numerous; the cobra lays twenty to thirty white, leathery eggs, which are hatched in some warm place by the natural heat. The viper is equally prolific. Some oviparous snakes are said to incubate; the cobra probably watches its eggs; the python is said to have been observed to coil itself round its eggs until hatched. Young vipers emerge from the oviduct alive, the process being expedited by the mother exposing herself in a warm, sunny place. The female of all snakes is said to be larger than the male. There may be differences in colour and slight variations in form, but no other prominent external characters distinguish the sexes.

Snakes hybernate in cold climates; returning warmth rouses them into activity. I have seen a python in the north-west of India, quite torpid in the early morning in the cold weather, roused to activity by the heat of the sun's rays. Snakes are carnivorous, and generally eat living creatures, but some will swallow eggs-the cobra sometimes robs the hen-roost-insects, molluscs, and even, it is said, vegetable matter; they prefer living prey, and some are cannibals—the ophiophagus and callophis, especially, live on snakes. In captivity they will, it is said, drink milk; needless to add that the bucolic tradition of robbing the cow is a myth.

Snakes differ in their habits and modes of life, and are grouped accordingly. Tree and grass snakes live in the trees, bushes, and grass, and are often coloured like the vegetation they frequent. When slender and active they are called whip snakes; innocent and poisonous forms are found among them. Ground snakes are found in all three sub-orders; they generally live above ground, and the great proportion of snakes, whether innocent or venomous, belong to this group.

Burrowing snakes live much underground, have a rigid, cylindrical body, short tail, narrow mouth, small teeth, and are all innocent.

There are fresh- and salt-water snakes. The salt-water snakes are peculiarly adapted for an aquatic life, and are all venomous; the fresh-water snakes have not the same characters as the hydrophidæ, or salt-water snakes, and are innocent--a curious fact! The hydrophidæ are viviparous.

It may be well here to say a few words on the structure of the jaws, teeth, and poison apparatus of the venomous snakes. The cranium is made up of a number of bones modified in accordance with the general structure and habits of the creature. It is only necessary to refer to these as far as concerns the mode in which the prey is seized and swallowed, and the poisonous wound inflicted. Deglutition is effected in a peculiar way: the prey being seized, the

mouth gapes laterally and vertically; each side of the jaws, having independent motion, is called separately into action, and the object grasped is slowly but surely drawn in; the sharp and recurved teeth hold it firmly as each side of the jaw alternately advances or relaxes its grasp; the prey is thus gradually but inevitably engulfed, the mouth and passages distending to an extraordinary degree. This is effected by the method in which the mandibles, maxillæ, and tympanic bones are articulated; the latter are long and slender, loosely articulated with the mastoid bones of the skull. At their distal extremities they articulate in a similar manner with the mandibles; these, again, are united in front by an elastic ligament. This allows of great stretching in all directions, enabling the snake to swallow an object much larger than itself in diameter.

The mandibles are closely set with sharp recurved teeth; the upper jaws, composed of the maxillary pterygoid and palatine bones. have also teeth. These with the premaxillary bones make up the maxillary arch.

The maxillary bones are characteristic in the venomous snakes, being much shorter and provided with fewer teeth than in the innocent snakes. In the latter they are elongated slips of bone set with small recurved teeth. In the poisonous colubrine snakes they are less elongated and have a fixed, large, tubular poison fang, several loose reserve fangs, and one, two, or more fixed smaller teeth which are not tubular and not directly connected with the poison apparatus. In the viperidæ the maxillary bone is a short triangular movable wedge furnished with one long tubular poison fang lying hidden in the mucous sheath. The movements of the poison fang as seen in the viperidæ are due to the rotation of the maxillary bone on its articulation with the skull, not to the mobility of the fang itself, the active poison fang in all snakes being firmly fixed in the maxillary bone. This mobility of the maxillary bone is very great in vipers, e.g. daboia, crotalus and pelias, whilst it is very slight in the poisonous colubrines.

The mechanism by which the fangs of a viper are reclined or erected is most curious and beautiful. When erected, the maxillary bone, into which the fang is inserted, is pushed forward by the external pterygoid bone, which is drawn forward by the action of the prespheno-pterygoid muscle. The muscular arrangement for opening and closing the mouth and at the same time compressing the poison gland, thereby injecting the venom through the tubular fang, is beautifully adapted to the purpose to be fulfilled.

It must suffice to mention the principal muscles. The temporals, masseters, and pterygoids are mainly concerned in closing the jaws and in compressing the poison gland; the prespheno-pterygoid erect the fang. There are other muscles which move the jaws, or help to steady the erect fang when in the act of biting, but these

need not be described. The poison glands are situated between the orbit and the tympanic bone. They are oval bodies, composed of lobes and lobules, which, having secreted the virus from the blood, which is abundantly supplied to the gland, force it through a duct which leads to and opens by a papilla into a capsule of mucous membrane, whence it finds its way into a triangular opening at the base of the fang, with which the papillary end of the duct is brought into close apposition, and thence it finds its way along a canal (to be described presently) into the wound. The poison glands are of various forms and sizes. In some snakes, as callophis, they are much elongated; in the cobra they are of the size and something of the shape of an almond. They are inclosed and fixed in situ by a fibrous capsule which is connected with a tendon, and are covered by the muscular fibres which compress them when the mouth is closed. The virus is a transparent, slightly viscid fluid, faintly acid in reaction, having something of the appearance of glycerine, of a faint yellow or straw colour-in the ophiophagus of a yellow colour-when dried, it forms a semi-crystalline substance, like gum Arabic. It is secreted in considerable quantities; and if a fresh, vigorous snake be made to bite a leaf stretched across a teaspoon-or, as the natives of India do it, with a mussel-shell-several drops may be obtained. It is exhausted when the snake has bitten frequently, but is rapidly reformed; in the interval the reptile is comparatively harmless, but soon becomes dangerous again. It has been shown that a vigorous cobra can kill several creatures before its bite becomes impotent, but the immunity is of short duration, the virus being rapidly resecreted. Removal of the fangs has the effect of rendering the snake temporarily harmless; but, as the reserve fangs (unless, indeed, they have all been removed) replace those which have been taken away, the snake soon becomes dangerous again, as has been proved by more than one fatal accident to the snake-charmers and others.

Some animals, especially the pig and the mongoose, are supposed to have immunity from snake-bite: fat sometimes protects the former, and the latter is so wiry and active that he frequently escapes with only a scratch; but, if either of them be fairly bitten in a vascular part, he succumbs like any other animal.

The chemistry of snake-poison has been made the subject of inquiry by Fontana, Prince L. Bonaparte, Armstrong, Gautier, and others, and recently by Drs. Weir Mitchell, and Reichert of the United States, the results of whose investigations were published in 1886. Gautier thought he had discovered a ptomaine in the venom of cobra, but they have been quite unable to verify this statement. They maintain that there are three distinct bodies in the venom : one is apparently harmless, while of the other two, which are proteids, one belongs to the globulins, the other to the peptones. The globulins, again, are of different kinds, and the investigators are of opinion