Who created an inhaler that controlled chloroform dosage?

• A. Louis Pasteur
• B. John Snow
• C. Ignaz Semmelweis
• D. Joseph Lister

Answer: (B)

This question tests how anesthesia was made safer by controlling dosage, using a device designed to regulate chloroform vapour. John Snow helped transform chloroform use from a general inhalation into a carefully managed dose by developing a chloroform inhaler. This device let the patient breathe in a measured amount of vapour, typically through a controlled flow via a small hole or dampening mechanism, so the anaesthetic could be increased or reduced in response to the patient’s breathing and reflexes. The key idea is that safe anaesthesia depended on watching and adjusting the dose rather than letting a large amount be inhaled at once, which reduced the risk of overdose and death. While the other figures made major contributions to medicine—Pasteur to germ theory, Semmelweis to antisepsis, and Lister to antiseptic surgery—they did not create an inhaler that controlled chloroform dosage.