Anaesthesia in new-born animals.

Pentobarbitone was more toxic to new-born than to adult rabbits and rats, produced a longer loss of righting reflex in new-born animals but did not anaesthetize them effectively in less than toxic doses. Urethane did not anaesthetize new-born animals in doses which anaesthetized adults. Ether produced loss of righting reflex at lower concentrations for new-born than for adults, but the new-born animals became anaesthetized more slowly.