commenting vs tract

commenting

noun
  • The making of a comment; commentary. 

tract

noun
  • A commentator's view or perspective on a subject. 

  • Part of the proper of the liturgical celebration of the Eucharist for many Christian denominations, used instead of the alleluia during Lenten or pre-Lenten seasons, in a Requiem Mass, and on a few other penitential occasions. 

  • A series of connected body organs, such as the digestive tract. 

  • Continued or protracted duration, length, extent 

  • A brief treatise or discourse on a subject. 

  • An area or expanse. 

  • A small booklet such as a pamphlet, often for promotional or informational uses. 

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