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This terrible reptile is found in great abundance on the continent of America; and if its instinct induced it to make use of the dreadful means of destruction and self-defence which it possesses, it would become so great a scourge as to render the parts in which it is found almost uninhabitable: but, except when violently irritated, or for the purpose of self-preservation, it seldom employs the fatal power bestowed upon it. The rattlesnake inserts its poison in the body of its victim by means of two long sharp-pointed teeth or fangs, which grow one on each side of the forepart of the upper jaw. The construction of these teeth is very singular; they are hollow for a portion of their length, and in each tooth is found a narrow slit communicating with the central hollow; the root of the fang rests on a kind of bag, containing a certain quantity of a liquid poison, and when the animal buries his teeth in his prey, a portion of this fluid is forced through these openings and lodged at the bottom of the wound. Another peculiarity of these poison teeth is, that when not in use they turn back, as it were, upon a hinge, and lie flat in the roof of the animal's mouth.

The name of rattlesnake is given to it on account of the singular apparatus with which the extremity of its tail is furnished. This consists of a series of hollow horn-like substances, placed loosely one behind the other in such a manner as to produce a kind of rattling noise when the tail is shaken; and as the animal, whenever it is enraged, always carries its tail raised up, and produces at the same time a tremulous motion in it, this provision of nature gives timely notice of its dangerous approach. The number of pieces of which this rattle is formed points out the age of the snake, which acquires a fresh piece every year. Some specimens have been found with as many as from forty to fifty, thus indicating a great age.

The poison of the Viper consists of a yellowish liquid, secreted in a glandular structure (situated immediately below the skin on either side of the head), which is believed to represent the parotid gland of the higher animals. If a viper be made to bite something solid, so as to avoid its poison, the following are the appearances under the microscope:—At first nothing is seen but a parcel of salts nimbly floating in the liquor, but in a very short time these saline particles shoot out into crystals of incredible tenuity and sharpness, with something like knots here and there, from which these crystals seem to proceed, so that the whole texture in a manner represents a spider's web, though infinitely finer and more minute. These spiculae, or darts, will remain unaltered on the glass for some months. Five or six grains of this viperine poison, mixed with half an ounce of human blood, received in a warm glass, produce no visible effects, either in colour or consistence, nor do portions of this poisoned blood, mixed with acids or alkalies, exhibit any alterations. When placed on the tongue, the taste is sharp and acrid, as if the tongue had been struck with something scalding or burning; but this sensation goes off in two or three hours. There are only five cases on record of death following the bite of the viper; and it has been observed that the effects are most virulent when the poison has been received on the extremities, particularly the fingers and toes, at which parts the animal, when irritated (as it were, by an innate instinct), always takes its aim.

F. T. BUCKLAND