Although nitrous oxide, or laughing gas, had been proposed as an anaesthetic as far back as 1799 by Humphry Davy, it was not until 1846 when an American dentist named William Morton started using ether on his patients that anaesthetics became common in the medical profession. In 1847 chloroform was introduced as an anaesthetic by James Young Simpson. Chloroform was favoured by doctors and hospital staff because it is much less flammable than ether, but critics complained that it could cause the patient to have a heart attack. Chloroform gained in popularity in England and Germany after John Snow gave Queen Victoria chloroform for the birth of her eighth child (Prince Leopold). By 1920, chloroform was used in 80 to 95% of all narcoses performed in the UK and German-speaking countries. A combination of antiseptics and anaesthetics helped surgeons operate more carefully and comfortably on their patients.