1911 Encyclopædia Britannica/Lethargy

LETHARGY (Gr. ληθαργία, from λήθη, forgetfulness), drowsiness, torpor. In pathology the term is used of a morbid condition of deep and lasting sleep from which the sufferer can be with difficulty and only temporarily aroused. The term Negro or African lethargy was formerly applied to the disease now generally known as “sleeping sickness” (q.v.).