Abstract: A system is provided for the delivery of a liquid anesthetic agent ti ab anesthetic vaporizer. The system includes a supply container having a spout defining an outlet through which the agent can be discharged. A reservoir is provided in the vaporizer for holding the agent, and a receiving station is provided on the vaporizer for receiving the container spout. The agent flows from the container through the spout by gravity into the reservoir. The container spout is located at the station to define the maximum liquid level of the agent in the vaporizer when gas flow into the container is blocked by the rising level of the liquid agent. In one embodiment, a frangible seal is provided in the container, an outlet valve is provided in the container, and an inlet valve is provided in the receiving station. The valves open automatically as the container is inserted into the receiving station of the vaporizer.