Abstract

1. During a 3-hour anesthesia the lethal dose 50 of vinyl ether is 0.19 cc. (1.71 millimols) per liter of air. This compares with 0.18 cc. (1.80 millimols) per liter of ethyl ether and 0.026 cc. (1.32 millimols) per liter of chloroform under the same experimental conditions.

2. The majority of white mice which survive a 3-hour exposure to vinyl ether die subsequently. No such late deaths are observed under identical conditions in rats. An explanation for these deaths cannot yet be given, since no macroscopic or microscopic changes of the organs have been found.

3. Vinyl ether does not decompose when recirculated through the body.

4. The acute toxicity of pure and of decomposed vinyl ether is about the same. Decomposed vinyl ether is less efficacious as an anesthetic than pure vinyl ether.

5. The difference in rapidity of action between ethyl ether and vinyl ether anesthesia depends upon the experimental conditions. In low anesthetic concentrations, ethyl ether is the quicker acting agent. In higher concentrations, vinyl ether acts more rapidly than ethyl ether.

6. The differences in induction time between ethyl ether and vinyl ether depend largely upon the temperature. They are greatest at low temperatures and smallest at 40°C. Recovery from vinyl ether is always much more rapid than from ethyl ether, regardless of temperature.