grey matter vs intellection

grey matter

noun
  • Brains; a person's ability to think. 

  • A collection of cell bodies and (usually) dendritic connections, in contrast to white matter. 

  • Literal brains as a general substance. 

intellection

noun
  • The mental content of an act of grasping by means of the intellect, as a thought, idea, or conception. 

  • The mental activity or process of grasping with the intellect; apprehension by the mind; understanding. 

  • A particular act of grasping by means of the intellect. 

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