introversion vs intussusception

introversion

noun
  • Arrangement of two similar words, lines, etc. to form the middle part of a structure. 

  • The action of turning one's thoughts upon internal or spiritual matters. 

  • A turning inward 

  • A personality orientation towards the self and mental abstraction; behavior expressing such orientation. 

intussusception

noun
  • The invagination of one portion of a tubular anatomical structure (especially intestines or blood vessels) within the next. 

  • Absorption. 

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