preceptor vs veterinary surgeon

preceptor

noun
  • A doctor who gives practical training to medical students, nurses etc. 

  • The head of a preceptory of Knights Templar. 

  • A teacher or tutor. 

veterinary surgeon

noun
  • A doctor who practices veterinary medicine. 

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