The United States Pharmacopeia, in the article on ether, (U. S. P. X) makes the following statement in italics: "Caution—Ether to be used for anesthesia must be preserved only in small, well-closed containers, and is not to be used for this purpose, if the original container has been opened longer than twenty-four hours."
This statement gives official sanction to the general practice in this country of using anesthetic ether chiefly in small cans of one-fourth and one-half pound. What remains in the can is usually regarded as unfit for anesthesia on the following day. Ordinary U. S. P. ether has been in use for many years in the laboratory of pharmacology of Cornell University Medical College for anesthesia in animals. Although this ether was taken from cans which had been opened many times, no ill effects were observed, but a systematic study of the question was not made.