Early anaesthetic (10)
(Other definitions for chloroform that I've seen before include "Sweet-smelling anaesthetic" , "Old anaesthetic" , "Solvent" , "Former anaesthetic" .)
(Other definitions for ether that I've seen before include "Rare atmosphere" , "Formerly an anaesthetic" , "Anaesthetic is, strangely, there" , "Volatile organic liquid once used as a general anaesthetic" , "Imaginary interstellar medium" .)