call it a night vs put to sleep

call it a night

verb
  • To go to bed to sleep. 

  • To cease what one has been doing for the night. 

put to sleep

verb
  • To help (someone) to bed; put to bed. 

  • To kill an animal painlessly, often with an injection; to euthanize. 

  • To give a general anesthetic prior to surgery. 

  • To cause (someone) to sleep. 

  • To render dormant. 

How often have the words call it a night and put to sleep occurred in a corpus of books? (source: Google Ngram Viewer )