There are two symptoms which characterize narcolepsy: (1) The patient has a tendency to go to sleep at frequent intervals through the day, the attacks of drowsiness often coming on at most inopportune times (while talking, walking, working or eating) and the desire to sleep being irrepressible; (2) the patient may find that any emotion causes a feeling of generalized weakness, so that his knees may give way under him and allow him to fall (the kataplektische Hemmung of Henneberg,1 the Lachschlag of Oppenheim,2 the affektiver Tonusverlust of Redlich3). Perrier4 described one patient, a soldier, who went to sleep on guard, and Spiller5 tells of one of his patients, a fireman on a locomotive, who went to sleep while holding on to the grabirons of a train said to be moving at a speed of about 70 miles an hour. The sleep of a narcoleptic