A study was made of the mechanism of ether, halothane and methoxyflurane functioning on the rabbit central nervous system with the following results:
1. All the drugs employed in arousal reaction following stimulation of the brain stem reticular formation, Ether and halothane acted more markedly on what was recorded from the cerebral cortex than on what was recorded from the hippocampus. Halothane inhibited arousal reaction in the cerebral cortex most markedly, followed by methoxyflurane and ether in order.
2. Against evoked muscular d ischarge in the rabbit fore and hind limbs following stimulation of the brain stem reticular formation, methoxyflurane showed the heighest threshold, followed by halothane and ether in order. Halothane and methoxyflurane showed little difference in an elevation of the threshold between the fore limbs and the hind limbs. But ether resulted in more elevation in the fore limbs than in the hind limbs.
3. Methoxyflurane little influenced the wave type of evoked muscular discharg e due to stimulation of the brain stem reticular formation. But ether and halothane tended to develop the tonic type muscular discharge.
4 Methoxyflurane inhibited evoke d muscular discharge due to stimulation of the cerebral cortex most markedly, followed by halothane and ether in order. Ether caused a change of the wave type of evoked muscular discharge from the tonic type to the TP type, while halothane and methoxyflurane showed no such obvious change.
5. Methoxyflurane inhibited evoked muscular discharge due to stim ulation of the hippocampus most markedly, followed by halothane and ether in order. Ether caused a change of the wave type of evoked muscular discharge into the phasic type, but halothane and methoxyflurane showed no such obvious change.
6. Ether markedly acted on the pyramidal truct, haloth ane and methoxyflurane acted on the pyramidal truct, but they acted more markedly on the extrapyramidal t r uct.
