Ether. Never used any more.
Chloroform or ether. Theoretically, any inhalational anesthetic gas can be used inappropriately in this manner. Originally ether and chloroform was used, or abused, this way as an anesthetic, but chloroform was found to have toxic side effects. Ether has since been replaced by more stable, reliable, and effective inhalational (gas) anesthetics like isoflurane, sevoflurane, and desflurane. Do not try this at home!
Chloroform. This is a very old anesthetic no longer used in medicine. This is probably not a very effective technique and victims probably were already somewhat weakened by alcohol or other drugs. Because the dose cannot be controlled, it could result in accidental death.
Chloroform or ether. Either chloroform or either, anesthetic agents no longer in common use, as there are better and much safer alternatives. It doesn't work as quickly as in the movies either. Inhalational induction of anesthesia is often used in children, but using a mask and modern agents like sevoflurane.
No need to know! I will not tell you because you have no need to know this information. An answer to this question could lead to inappropriate use. Remember propofol?