phlegm vs rheum

phlegm

noun
  • One of the four humors making up the body in ancient and mediaeval medicine; said to be cold and moist, and often identified with mucus. 

  • Calmness of temperament, composure; also seen negatively, sluggishness, indifference. 

  • Viscid mucus produced by the body, later especially mucus expelled from the bronchial passages by coughing. 

  • A watery distillation, especially one obtained from plant matter; an aqueous solution. 

rheum

noun
  • Watery or thin discharge of serum or mucus, especially from the eyes or nose, formerly thought to cause disease. 

  • Tears. 

  • Illness or disease thought to be caused by such secretions; a catarrh, a cold; rheumatism. 

How often have the words phlegm and rheum occurred in a corpus of books? (source: Google Ngram Viewer )