introduce vs necropsy

introduce

verb
  • To bring (something) into practice. 

  • To cause (someone) to be acquainted (with someone else). 

  • To add (something) to a system, a mixture, or a container. 

  • To make (something or someone) known by formal announcement or recommendation. 

necropsy

verb
  • The act of performing a necropsy. 

noun
  • The pathological examination of a corpse, particularly to determine cause of death. 

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