bloodhound vs sleuthhound

bloodhound

noun
  • A detective or other person skilled at finding people or clues. 

  • A large scenthound famed for its ability to follow a scent many days old, over vast distances. This dog is often used as a police dog to track missing people, fleeing suspects, or escaped prisoners. 

sleuthhound

noun
  • A detective; a sleuth. 

  • A working dog who tracks or pursues e.g. a wanted criminal; a bloodhound formerly used in Scotland. 

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