Possible Clues:

• Nonessential internal organ
• In spite of casing for split screen
• Quick temper — spite
• Lymphocyte producer
• Stomach neighbor
• Suppressed anger
• Viewed about a little plural for ill-humour
• Organ once thought to be the seat of anger
• One supplanted by general in revolution shows bad temper
• In you to make you out of sorts, even at last