Chloroform inhaler. Illustration of a chloroform inhaler used in the 1850s by the British anaesthetist John Snow. The mask was made of lead and moulded to the patient's features. As the patient drew in breath, the air became impregnated with chloroform in the chamber at lower right. Chloroform's (or trichloromethane) anaesthetic properties had been discovered in 1847 by the Scottish physician James Simpson. There was much opposition to the use of anaesthesia in childbirth because a painful labour was believed to be a religious and biological necessity. The procedure became accepted after Queen Victoria used chloro- form in 1853 for the birth of her seventh child.