RATTLESNAKE, a distinctively Ameri can group of poisonous serpents characterized by a peculiar horny rattle appended to the tail. They belong to the suborder Solenoglypha, all the members of which are poisonous and have the fang-bearing maxillary bones erectile. To this suborder belong the Old World families of Viperide (vipers) and the Crotalider, or pit vipers, which inhabit both hemispheres. The latter have the maxillary bone deeply excavated to lodge a sensory pit of unknown function opening on the face between the eye and nostril. There are two subfamilies, the Lachesis., which have no caudal rattle, and the Croton's., or rat tlesnakes. The former includes the copper head, water moccasin and fer-de-lance (qq.v.). the banana snake, whose presence in bunches of this fruit so often causes consternation on fruit ships and in storage houses, and numerous others of tropical America, India and the Malay Islands.
The Crotalina, or rattlesnakes, represent the highest type of serpent development and spe cialization. The caudal rattle, from which they take their name, consists of a series of dry horny epidermal rings so loosely fitted that any movement causes them to knock together with a sharp rustling rattle. They are formed in the following manner: Several of the terminal vertebra of the tail are coalesced to form a dilated vertically enlarged plate. This is cov ered with a thick vascular skin so cut by an annular constriction as to form a larger an terior, and a smaller posterior knob, which to gether may be considered to be a mold on which the joints of the rattle are formed. The epidermis covering this region is especially thick, and in the young snake forms a button and ring, which are the only indications of the rattle. When the snake sloughs, the horny cov ering is loosened here as elsewhere and a new layer is formed beneath it; but instead of being cast off with the rest of the epidermis, the open end of the old horny ring fits over and by its elasticity clasps the new knob at the end of the tail, and by this means remains attached. With each subsequent molt a new ring and button are added, the latter serving to hold its prede cessor in the series, and which continues to in crease in size with the growth of the snake and its caudal knob. As well-fed snakes may slough three or four times a year, and as the rings sooner or later become worn out and detached, it is evident that the popular belief that the number of joints in the rattle indicate the years of the snake's age is unfounded. Rattles of more than 12 joints are rare, but one having 21 is known. When the snakes are irritated or angry, the end of the tail is more or less ele vated and vibrated rapidly, producing a sound audible at a distance of 30 or 40 paces. Many snakes, both venomous and innocuous, have this habit of vibrating the tip of the tail when angry and many have a hard horny spur or cap at its end, but no others retain this through a suc cession of molts. Many fantastic theories have been proposed in explanation of the utility of the rattle, but it is probably little more than a recognition character, which helps to bring the sexes together and to segregate the species. However, it is probable that its sounding for• merly saved the lives of many. rattlesnakes by warning large animals acquainted with their deadly powers from the vicinity, but since the advent of the white man it has had a precisely opposite result.
Poison.— The venom apparatus of the rattlesnakes is the most complete and effective contrivance imaginable for injecting the poison ous fluid into the circulation of a victim. The maxillary bones are very short and are freely movable on an articulation with the prefontals. Upon them are attached the venom fangs at such an angle that with the movements of the maxillary they may be depressed in a fold of mucous membrane or erected vertically in the very front of the mouth in a most effective position for striking. The tooth substance of the fang is folded into a tubular form, with an opening at the base to receive the end of the venom duct and another near the front face of the needle-pointed tip. Behind the functional fang, which may be nearly an inch long in large snakes, is a succession of smaller reserve fangs, which become functional in order as their prede cessors are lost. The venom gland, which cor responds to the parotid salivary gland of other animals, is situated on the cheek and has a duct running to a sinus at the base of the fang. All of the muscles and other parts are so arranged that the same movements that open the mouth and press the horizontal pterygoid bones for ward to erect the maxillaries with their fangs also compress the poison gland and squeeze out its secretion. Cope describes the biting move anent as three-fold: *First, there is the spring of the body, which never exceeds two-thirds of its length; second, the bite proper, caused by the seizing of the jaws; and, third, the dutch with the fangs themselves, which are moved freely backward and forward" This movement of the fangs may be easily seen by holding a rattlesnake so that it cannot strike, when drops of the pale yellow venom may be seen to fall from their tips and are sometimes blown from the month by forcible expirations. The active -principles of the venom are several soluble pro teids, one of which has a disorganizing effect on tissues with which it comes in contact and another is a powerful heart and respiratory de pressor. The immediate effect of a bite is severe burning followed in 10 or 15 min utes by prostration, with dizziness, vomiting and cold sweats; the heart action is very feeble and the pupil dilated. This condition gives way in from 12 to 15 hours to one of fever and difficult respiration, while the part affected becomes greatly swollen and the neighborhood of the wound suppurates. Death may occur in either of these stages or as a result of secondary gan grene. Treatment to be effective must be prompt and thorough. A ligature should be applied above the wound and the latter enlarged with a dean knife until the blood flows freely. Permanganate of potash, bleaching powder, chromic acid, silver nitrate or other substances which render the active albumens insoluble should be applied to the wound. Small and fre quent doses of whisky, strychnine or ammonia should be administered as a stimulant, but an excess of alcohol may increase the depression. Every effort should be made to press or draw the poison from the wound before the ligature is removed, but sucking with the mouth is al ways dangerous.