This paper gives some account and results of work conducted on the properties of ethylene oxide, as this compound has been recommended as an insecticide and vermin destroyer, and what is of more importance, as a fumigant for foodstuffs. The concentration recommended is in the nature of 2 lb. per 1000 c. ft. (or 1 part in 60) for 24 hours. It has also been mentioned as a possible agent for use as a lachrymator in war.