Trichlorethylene, a strong, sweet smelling white liquid, was used in Germany during the Great War for removing grease from the metal parts of machinery and was also contained in a varnish used to cover the supporting surfaces of airplanes. Plessner,1 in 1915, presented before the Berlin Medical Society four workers suffering from the chronic effects of an acute poisoning. A study of these workers showed that they were exposed to trichlorethylene, and it was to this drug that these symptoms were attributed. Immediately following the exposure to this drug, these men developed vertigo, nausea, vomiting, swelling of the optic disks and bilateral anesthesia of the trigeminal area, without motor involvement. Within a few weeks, these acute symptoms subsided. At the time of Plessner's presentation, eight months had elapsed since their exposure. Clinically these men had a bilateral loss of sensation definitely confined to the trigeminal distribution of the face;