mitigatory vs paregoric

mitigatory

adj
  • reducing, lessening the effects of something, generally something painful or uncomfortable 

paregoric

adj
  • Assuaging or soothing pain. 

noun
  • A painkiller; a medicine which soothes or relieves pain; specifically the traditional patent medicine consisting of camphorated tincture of opium. 

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