1911 Encyclopædia Britannica/Spleen

SPLEEN (Gr. σπλήν), a vascular organ situated on the left side of the abdomen (see 1911 Encyclopædia Britannica/Ductless Glands). It was supposed in olden times to be the seat of ill-humour and melancholy, whence such phrases as "to have the spleen," to be out of temper, sulky, morose, "splenetic."