concuss vs succuss

concuss

verb
  • To injure the brain of, usually temporarily, by violent impact. 

  • To force to do something, or give up something, by intimidation; to coerce. 

succuss

verb
  • To shake a patient to detect fluids or air in the body. 

  • To shake with vigor. 

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