emotion vs fervor

emotion

noun
  • A person's internal state of being and involuntary physiological response to an object or a situation, based on or tied to physical state and sensory data. 

  • A reaction by a non-human organism with behavioral and physiological elements similar to a person's response. 

fervor

noun
  • An intense, heated emotion; passion, ardor. 

  • Heat. 

  • A passionate enthusiasm for some cause. 

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