bloodletting vs cruor

bloodletting

noun
  • The archaic practice of treating illness by removing some blood, believed to be tainted, from the stricken person. 

  • The diminishment of any resource with the hope that this will lead to a positive effect. 

  • A circumstance, such as a battle, where a large amount of blood is likely to be spilled through violence. 

cruor

noun
  • The clotted portion of coagulated blood, containing the colouring matter; gore. 

  • The colouring matter of the blood. 

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