Surgeons commonly agree that nitrous oxid is the safest general anesthetic known. Bevan estimates the death rate to be one in fifty thousand. Hewitt was able to collect records of seventeen deaths only from 1860 to 1900.
Ethyl chlorid has produced already thirty deaths in Great Britain alone.
Nitrous oxid is used by dentists, who employ it with great facility for the extraction of teeth. Thomas, of Philadelphia, has administered it 271,940 times with only one death, which occurred five hours after the administration, and was due to apoplexy. This case is included in Hewitt's report of seventeen fatalities.
Nitrous oxid has also been employed rather extensively to induce the anesthesia which is maintained later with ether. This method contributes greatly to the comfort of the patient in avoiding the disagreeable sensations of "going under" ether. The Bennett gas-ether inhaler popularized the method, but the plan has not yet come
Haggard WD. NITROUS OXID ANESTHESIA.. JAMA. 1908;LI(19):1576-1578. doi:10.1001/jama.1908.25410190014001f