currently available equipment (AVMA, 1986). Standard kitchen microwave appliances are not appropriate, because their beams are diffuse and animals might experience severe pain or distress.
Double pithing is an effective method of killing some poikilotherms (cold-blooded animals). A sharp needle with a diameter appropriate to the size of the animal is quickly inserted in a cranial direction through the foramen magnum and is rotated so as to crush the brain bilaterally. The needle is then inserted in a caudal direction at the same point of entry and rotated to destroy the spinal cord. Pithing requires dexterity and skill and should be conducted only by trained personnel.
Rapid freezing is used by neurobiologists, because it instantaneously inactivates enzymes in the brain. Immersion of the entire animal in liquid nitrogen achieves rapid death of an animal that weighs less than 40 g. Heavier animals should be anesthetized before this technique is used. Suitable equipment and properly trained personnel are required.
Because of the anxiety associated with extreme hypovolemia, exsanguination should be done only in sedated, stunned, or anesthetized animals (AVMA, 1986).
Several noninhalational agents are used for euthanasia. Although death can be induced by administering these drugs by several routes, intravenous administration is preferred, because of its smooth induction, rapid action, and reliability. Intrapulmonic injection should be avoided. Intracardiac injection should be used discriminatingly, because it requires considerable skill; the injection might be painful, and, if the drug is accidentally discharged outside the heart, death will be slow and painful. Intracardiac injection of drugs is recommended only for moribund, anesthetized, or comatose animals. Intraperitoneal administration requires higher doses and leads to prolonged dying, and induction can be marked by ataxia and struggling.
The barbiturates are used extensively and are considered the agents of choice for most euthanasia on both aesthetic and scientific bases. Barbiturates are humane, safe, and efficient when properly administered. Intravenous administration of a