Surgical Removal of the Poison Glands of Rattlesnakes

Abstract

T HE complete removal of the venom glands in poisonous snakes is apparently not a common operation. The writer, who began his attempts to render captive rattlesnakes safe by extracting both the fixed and the reserve fangs, soon discovered, as others had found before him, that this procedure is usually followed by a mouth infection, to which the animals succumb in spite of all subsequent efforts at disinfection of the wounds. Consequently the safer but more elaborate operation of taking away the poison glands was devised. The purpose of deglanding the snakes was to render them more readily amenable in physiological experimentation. A certain amount of technical equipment is necessary for the operation; also the help of an assistant to bind the snake, to act as anesthetist, to prepare the tray of aseptic instruments, to hand ligatures, etc.-for only the operator need have his hands sterilized. Were one to work single-handed, one would employ a water-soluble anesthetic, e.g. dial or nembutal, by means of which the subject may be rendered and kept inert for long hours on end. It is only because rapid recovery of the animals was desired that volatile anesthetics were in general preferred to those whose action is longer lasting. The snake is placed at first in a glass-covered box containing dilute chloroform vapor. There it is left for a matter of twenty minutes to threequarters of an hour. After its head has drooped and it has ceased to respond to prodding stimulation, but before its body has become limp and lost its tone, it is laid lengthwise on a flat board placed on a narrow animal table. With strips of sticking-plaster, arranged at intervals athwart its body and secured to the wood with thumb tacks, the subject is gullivered to the board. If the snakes are of uniform size, any one of them can equally well be held by being dropped, tail first, into a brass tube of suitable diameter and of a length sufficient just to leave the head and neck and the muscular part of the tail free at the ends. A transverse bar of metal soldered to the tube keeps it from rolling. With this device it suffices to apply sticking-plaster only to the neck and to the tail. At all times, but particularly when the subject is a large and powerful one, it is necessary to give careful attention to the fixing of the neck. A glass tube, connected to a rhythmically acting air-pump and ether bottle, is then inserted into the trachea. The sides and top of the head are next painted with tincture of iodine. The tracheal tube is momentarily removed, and the area of operation covered with a dry sterile cloth so slit as to allow only the head to protrude. On second insertion of the tracheal tube, this time on top of the sterile cloth, the animal is ready for operation. The depth of anesthesia is gauged at intervals by observing (1) any spontaneous bodily movements, (2) reflex withdrawal of the tongue when it is grasped with forceps, (3) reflex coiling of the tail when the area of black skin at the base of the rattle is tweaked. In general the anesthesia is so adjusted as to abolish all spontaneous movement and yet leave the former of these two reflexes present. Total abolition of the tongue reflex means unduly deep anesthesia. As in any surgical operation, sudden cessation of hemorrhage at any stage is an indication that the circulation is failing from overdosage