The plane of surgical anesthesia during ether anesthesia is defined as:
Stage of surgical anesthesia extends from onset of regular respiration to cessation of spontaneous breathing. This has been divided into four planes. Loss of consciousness to beginning of regular respiration is stage of delirium. From KD Tripati 7th edition Page no 374
Loss of consciousness
Loss of consciousness to the onset of spontaneous respiration
From onset of regular respiration to cessation of spontaneous breathing
Absence of reflexes
Anesthesia