TEMPERATURE DEPENDENCE OF ANESTHESIA IN GOLDFISH.

The anesthetizing concentrations in water of diethyl ether, chloroform, halothane (CF(3)CClBrH), and methaxyflurane (CHCl(2)CF(2)OCH(3)) have been determined for temperature-acclimated goldfish (Carassius auratus) at 5 degrees to 30 degrees C. At 20 degrees C, the concentrations that anesthetize 50 percent of the fish are 2160, 167, 76.4, and 57.0 mg/ liter, respectively; the corresponding partial pressures are 13.0, 3.36, 4.12, and 0.67 mm-Hg. The anesthetizing partial pressures increase with body temperature, with enthalpies of 8.6, 13.2, 12.5, and 12.3 kcal/ mole, respectively.