emotion vs enthusiasm

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. 

enthusiasm

noun
  • Intensity of feeling; excited interest or eagerness. 

  • Something in which one is keenly interested. 

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